-<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.156 2007/09/03 00:39:11 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.157 2007/09/05 18:10:47 tgl Exp $ -->
<!--
Documentation of the system catalogs, directed toward PostgreSQL developers
-->
There are several distinct types of lockable objects:
whole relations (e.g., tables), individual pages of relations,
individual tuples of relations,
- transaction IDs,
+ transaction IDs (both virtual and permanent IDs),
and general database objects (identified by class OID and object OID,
in the same way as in <structname>pg_description</structname> or
<structname>pg_depend</structname>). Also, the right to extend a
<literal>page</>,
<literal>tuple</>,
<literal>transactionid</>,
+ <literal>virtualxid</>,
<literal>object</>,
<literal>userlock</>, or
<literal>advisory</>
Tuple number within the page, or NULL if the object is not a tuple
</entry>
</row>
+ <row>
+ <entry><structfield>virtualxid</structfield></entry>
+ <entry><type>text</type></entry>
+ <entry></entry>
+ <entry>
+ Virtual ID of a transaction, or NULL if the object is not a
+ virtual transaction ID
+ </entry>
+ </row>
<row>
<entry><structfield>transactionid</structfield></entry>
<entry><type>xid</type></entry>
</entry>
</row>
<row>
- <entry><structfield>transaction</structfield></entry>
- <entry><type>xid</type></entry>
+ <entry><structfield>virtualtransaction</structfield></entry>
+ <entry><type>text</type></entry>
<entry></entry>
<entry>
- ID of the transaction that is holding or awaiting this lock
+ Virtual ID of the transaction that is holding or awaiting this lock
</entry>
</row>
<row>
</para>
<para>
- Every transaction holds an exclusive lock on its transaction ID for its
- entire duration. If one transaction finds it necessary to wait specifically
+ Every transaction holds an exclusive lock on its virtual transaction ID for
+ its entire duration. If a permanent ID is assigned to the transaction
+ (which normally happens only if the transaction changes the state of the
+ database), it also holds an exclusive lock on its permanent transaction ID
+ until it ends. When one transaction finds it necessary to wait specifically
for another transaction, it does so by attempting to acquire share lock on
- the other transaction ID. That will succeed only when the other transaction
+ the other transaction ID (either virtual or permanent ID depending on the
+ situation). That will succeed only when the other transaction
terminates and releases its locks.
</para>
and therefore row-level locks normally do not appear in this view.
If a transaction is waiting for a
row-level lock, it will usually appear in the view as waiting for the
- transaction ID of the current holder of that row lock.
+ permanent transaction ID of the current holder of that row lock.
</para>
<para>
</para>
<para>
- If you have enabled the statistics collector, the
- <structfield>pid</structfield> column can be joined to the
+ The <structfield>pid</structfield> column can be joined to the
<structfield>procpid</structfield> column of the
<structname>pg_stat_activity</structname> view to get more
- information on the session holding or waiting to hold the lock.
+ information on the session holding or waiting to hold each lock.
Also, if you are using prepared transactions, the
<structfield>transaction</> column can be joined to the
<structfield>transaction</structfield> column of the
-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.141 2007/08/22 04:45:20 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.142 2007/09/05 18:10:47 tgl Exp $ -->
<chapter Id="runtime-config">
<title>Server Configuration</title>
<entry>Process start time stamp</entry>
<entry>no</entry>
</row>
+ <row>
+ <entry><literal>%v</literal></entry>
+ <entry>Virtual transaction ID (backendID/localXID)</entry>
+ <entry>no</entry>
+ </row>
<row>
<entry><literal>%x</literal></entry>
- <entry>Transaction ID</entry>
- <entry>yes</entry>
+ <entry>Transaction ID (0 if none is assigned)</entry>
+ <entry>no</entry>
</row>
<row>
<entry><literal>%q</literal></entry>
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.237 2007/08/14 17:35:18 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.238 2007/09/05 18:10:47 tgl Exp $
*
*
* INTERFACE ROUTINES
MarkBufferDirty(buffer);
/* XLOG stuff */
- if (relation->rd_istemp)
- {
- /* No XLOG record, but still need to flag that XID exists on disk */
- MyXactMadeTempRelUpdate = true;
- }
- else if (use_wal)
+ if (use_wal && !relation->rd_istemp)
{
xl_heap_insert xlrec;
xl_heap_header xlhdr;
PageSetLSN(dp, recptr);
PageSetTLI(dp, ThisTimeLineID);
}
- else
- {
- /* No XLOG record, but still need to flag that XID exists on disk */
- MyXactMadeTempRelUpdate = true;
- }
END_CRIT_SECTION();
PageSetLSN(BufferGetPage(buffer), recptr);
PageSetTLI(BufferGetPage(buffer), ThisTimeLineID);
}
- else
- {
- /* No XLOG record, but still need to flag that XID exists on disk */
- MyXactMadeTempRelUpdate = true;
- }
END_CRIT_SECTION();
PageSetLSN(dp, recptr);
PageSetTLI(dp, ThisTimeLineID);
}
- else
- {
- /* No XLOG record, but still need to flag that XID exists on disk */
- MyXactMadeTempRelUpdate = true;
- }
END_CRIT_SECTION();
-$PostgreSQL: pgsql/src/backend/access/transam/README,v 1.6 2007/08/01 22:45:07 tgl Exp $
+$PostgreSQL: pgsql/src/backend/access/transam/README,v 1.7 2007/09/05 18:10:47 tgl Exp $
The Transaction System
----------------------
explicit transaction block has been established, while DefineSavepoint is not.
-Subtransaction numbering
-------------------------
+Transaction and subtransaction numbering
+----------------------------------------
-A top-level transaction is always given a TransactionId (XID) as soon as it is
-created. This is necessary for a number of reasons, notably XMIN bookkeeping
-for VACUUM. However, a subtransaction doesn't need its own XID unless it
-(or one of its child subxacts) writes tuples into the database. Therefore,
-we postpone assigning XIDs to subxacts until and unless they call
-GetCurrentTransactionId. The subsidiary actions of obtaining a lock on the
-XID and and entering it into pg_subtrans and PG_PROC are done at the same time.
+Transactions and subtransactions are assigned permanent XIDs only when/if
+they first do something that requires one --- typically, insert/update/delete
+a tuple, though there are a few other places that need an XID assigned.
+If a subtransaction requires an XID, we always first assign one to its
+parent. This maintains the invariant that child transactions have XIDs later
+than their parents, which is assumed in a number of places.
+
+The subsidiary actions of obtaining a lock on the XID and and entering it into
+pg_subtrans and PG_PROC are done at the time it is assigned.
+
+A transaction that has no XID still needs to be identified for various
+purposes, notably holding locks. For this purpose we assign a "virtual
+transaction ID" or VXID to each top-level transaction. VXIDs are formed from
+two fields, the backendID and a backend-local counter; this arrangement allows
+assignment of a new VXID at transaction start without any contention for
+shared memory. To ensure that a VXID isn't re-used too soon after backend
+exit, we store the last local counter value into shared memory at backend
+exit, and initialize it from the previous value for the same backendID slot
+at backend start. All these counters go back to zero at shared memory
+re-initialization, but that's OK because VXIDs never appear anywhere on-disk.
Internally, a backend needs a way to identify subtransactions whether or not
they have XIDs; but this need only lasts as long as the parent top transaction
CommandId in that it's generated from a counter that we reset at the start of
each top transaction. The top-level transaction itself has SubTransactionId 1,
and subtransactions have IDs 2 and up. (Zero is reserved for
-InvalidSubTransactionId.)
+InvalidSubTransactionId.) Note that subtransactions do not have their
+own VXIDs; they use the parent top transaction's VXID.
pg_clog and pg_subtrans
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/access/transam/clog.c,v 1.43 2007/08/01 22:45:07 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/clog.c,v 1.44 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/*
* Write a ZEROPAGE xlog record
- *
- * Note: xlog record is marked as outside transaction control, since we
- * want it to be redone whether the invoking transaction commits or not.
- * (Besides which, this is normally done just before entering a transaction.)
*/
static void
WriteZeroPageXlogRec(int pageno)
rdata.len = sizeof(int);
rdata.buffer = InvalidBuffer;
rdata.next = NULL;
- (void) XLogInsert(RM_CLOG_ID, CLOG_ZEROPAGE | XLOG_NO_TRAN, &rdata);
+ (void) XLogInsert(RM_CLOG_ID, CLOG_ZEROPAGE, &rdata);
}
/*
*
* We must flush the xlog record to disk before returning --- see notes
* in TruncateCLOG().
- *
- * Note: xlog record is marked as outside transaction control, since we
- * want it to be redone whether the invoking transaction commits or not.
*/
static void
WriteTruncateXlogRec(int pageno)
rdata.len = sizeof(int);
rdata.buffer = InvalidBuffer;
rdata.next = NULL;
- recptr = XLogInsert(RM_CLOG_ID, CLOG_TRUNCATE | XLOG_NO_TRAN, &rdata);
+ recptr = XLogInsert(RM_CLOG_ID, CLOG_TRUNCATE, &rdata);
XLogFlush(recptr);
}
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/access/transam/multixact.c,v 1.24 2007/08/01 22:45:07 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/multixact.c,v 1.25 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/*
* Write an xlog record reflecting the zeroing of either a MEMBERs or
* OFFSETs page (info shows which)
- *
- * Note: xlog record is marked as outside transaction control, since we
- * want it to be redone whether the invoking transaction commits or not.
*/
static void
WriteMZeroPageXlogRec(int pageno, uint8 info)
rdata.len = sizeof(int);
rdata.buffer = InvalidBuffer;
rdata.next = NULL;
- (void) XLogInsert(RM_MULTIXACT_ID, info | XLOG_NO_TRAN, &rdata);
+ (void) XLogInsert(RM_MULTIXACT_ID, info, &rdata);
}
/*
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/transam/twophase.c,v 1.32 2007/08/01 22:45:07 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/twophase.c,v 1.33 2007/09/05 18:10:47 tgl Exp $
*
* NOTES
* Each global transaction is associated with a global transaction
MemSet(&gxact->proc, 0, sizeof(PGPROC));
SHMQueueElemInit(&(gxact->proc.links));
gxact->proc.waitStatus = STATUS_OK;
+ gxact->proc.lxid = InvalidLocalTransactionId;
gxact->proc.xid = xid;
gxact->proc.xmin = InvalidTransactionId;
gxact->proc.pid = 0;
+ gxact->proc.backendId = InvalidBackendId;
gxact->proc.databaseId = databaseid;
gxact->proc.roleId = owner;
gxact->proc.inCommit = false;
hdr.prepared_at = gxact->prepared_at;
hdr.owner = gxact->owner;
hdr.nsubxacts = xactGetCommittedChildren(&children);
- hdr.ncommitrels = smgrGetPendingDeletes(true, &commitrels);
- hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels);
+ hdr.ncommitrels = smgrGetPendingDeletes(true, &commitrels, NULL);
+ hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels, NULL);
StrNCpy(hdr.gid, gxact->gid, GIDSIZE);
save_state_data(&hdr, sizeof(TwoPhaseFileHeader));
}
rdata[lastrdata].next = NULL;
- recptr = XLogInsert(RM_XACT_ID,
- XLOG_XACT_COMMIT_PREPARED | XLOG_NO_TRAN,
- rdata);
+ recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_COMMIT_PREPARED, rdata);
/*
* We don't currently try to sleep before flush here ... nor is there
}
rdata[lastrdata].next = NULL;
- recptr = XLogInsert(RM_XACT_ID,
- XLOG_XACT_ABORT_PREPARED | XLOG_NO_TRAN,
- rdata);
+ recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_ABORT_PREPARED, rdata);
/* Always flush, since we're about to remove the 2PC state file */
XLogFlush(recptr);
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.247 2007/09/03 00:39:13 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.248 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "storage/fd.h"
#include "storage/lmgr.h"
#include "storage/procarray.h"
+#include "storage/sinvaladt.h"
#include "storage/smgr.h"
#include "utils/combocid.h"
#include "utils/flatfiles.h"
/* local function prototypes */
-static void AssignSubTransactionId(TransactionState s);
+static void AssignTransactionId(TransactionState s);
static void AbortTransaction(void);
static void AtAbort_Memory(void);
static void AtCleanup_Memory(void);
SubTransactionId parentSubid);
static void CleanupTransaction(void);
static void CommitTransaction(void);
-static void RecordTransactionAbort(void);
+static void RecordTransactionAbort(bool isSubXact);
static void StartTransaction(void);
static void RecordSubTransactionCommit(void);
/*
* GetTopTransactionId
*
- * Get the ID of the main transaction, even if we are currently inside
- * a subtransaction. If we are not in a transaction at all, or if we
- * are in transaction startup and haven't yet assigned an XID,
- * InvalidTransactionId is returned.
+ * This will return the XID of the main transaction, assigning one if
+ * it's not yet set. Be careful to call this only inside a valid xact.
*/
TransactionId
GetTopTransactionId(void)
{
+ if (!TransactionIdIsValid(TopTransactionStateData.transactionId))
+ AssignTransactionId(&TopTransactionStateData);
return TopTransactionStateData.transactionId;
}
+/*
+ * GetTopTransactionIdIfAny
+ *
+ * This will return the XID of the main transaction, if one is assigned.
+ * It will return InvalidTransactionId if we are not currently inside a
+ * transaction, or inside a transaction that hasn't yet been assigned an XID.
+ */
+TransactionId
+GetTopTransactionIdIfAny(void)
+{
+ return TopTransactionStateData.transactionId;
+}
/*
* GetCurrentTransactionId
*
- * We do not assign XIDs to subtransactions until/unless this is called.
- * When we do assign an XID to a subtransaction, recursively make sure
- * its parent has one as well (this maintains the invariant that a child
- * transaction has an XID following its parent's).
+ * This will return the XID of the current transaction (main or sub
+ * transaction), assigning one if it's not yet set. Be careful to call this
+ * only inside a valid xact.
*/
TransactionId
GetCurrentTransactionId(void)
TransactionState s = CurrentTransactionState;
if (!TransactionIdIsValid(s->transactionId))
- AssignSubTransactionId(s);
-
+ AssignTransactionId(s);
return s->transactionId;
}
+/*
+ * GetCurrentTransactionIdIfAny
+ *
+ * This will return the XID of the current sub xact, if one is assigned.
+ * It will return InvalidTransactionId if we are not currently inside a
+ * transaction, or inside a transaction that hasn't been assigned an XID yet.
+ */
+TransactionId
+GetCurrentTransactionIdIfAny(void)
+{
+ return CurrentTransactionState->transactionId;
+}
+
+
+/*
+ * AssignTransactionId
+ *
+ * Assigns a new permanent XID to the given TransactionState.
+ * We do not assign XIDs to transactions until/unless this is called.
+ * Also, any parent TransactionStates that don't yet have XIDs are assigned
+ * one; this maintains the invariant that a child transaction has an XID
+ * following its parent's.
+ */
static void
-AssignSubTransactionId(TransactionState s)
+AssignTransactionId(TransactionState s)
{
+ bool isSubXact = (s->parent != NULL);
ResourceOwner currentOwner;
- Assert(s->parent != NULL);
+ /* Assert that caller didn't screw up */
+ Assert(!TransactionIdIsValid(s->transactionId));
Assert(s->state == TRANS_INPROGRESS);
- if (!TransactionIdIsValid(s->parent->transactionId))
- AssignSubTransactionId(s->parent);
+
+ /*
+ * Ensure parent(s) have XIDs, so that a child always has an XID later
+ * than its parent.
+ */
+ if (isSubXact && !TransactionIdIsValid(s->parent->transactionId))
+ AssignTransactionId(s->parent);
/*
* Generate a new Xid and record it in PG_PROC and pg_subtrans.
* PG_PROC, the subtrans entry is needed to ensure that other backends see
* the Xid as "running". See GetNewTransactionId.
*/
- s->transactionId = GetNewTransactionId(true);
+ s->transactionId = GetNewTransactionId(isSubXact);
- SubTransSetParent(s->transactionId, s->parent->transactionId);
+ if (isSubXact)
+ SubTransSetParent(s->transactionId, s->parent->transactionId);
/*
- * Acquire lock on the transaction XID. (We assume this cannot block.) We
- * have to be sure that the lock is assigned to the transaction's
- * ResourceOwner.
+ * Acquire lock on the transaction XID. (We assume this cannot block.)
+ * We have to ensure that the lock is assigned to the transaction's
+ * own ResourceOwner.
*/
currentOwner = CurrentResourceOwner;
PG_TRY();
{
CurrentResourceOwner = s->curTransactionOwner;
-
XactLockTableInsert(s->transactionId);
}
PG_CATCH();
}
-/*
- * GetCurrentTransactionIdIfAny
- *
- * Unlike GetCurrentTransactionId, this will return InvalidTransactionId
- * if we are currently not in a transaction, or in a transaction or
- * subtransaction that has not yet assigned itself an XID.
- */
-TransactionId
-GetCurrentTransactionIdIfAny(void)
-{
- TransactionState s = CurrentTransactionState;
-
- return s->transactionId;
-}
-
-
/*
* GetCurrentSubTransactionId
*/
void
RecordTransactionCommit(void)
{
+ TransactionId xid = GetTopTransactionIdIfAny();
+ bool markXidCommitted = TransactionIdIsValid(xid);
int nrels;
RelFileNode *rels;
+ bool haveNonTemp;
int nchildren;
TransactionId *children;
/* Get data needed for commit record */
- nrels = smgrGetPendingDeletes(true, &rels);
+ nrels = smgrGetPendingDeletes(true, &rels, &haveNonTemp);
nchildren = xactGetCommittedChildren(&children);
/*
- * If we made neither any XLOG entries nor any temp-rel updates, and have
- * no files to be deleted, we can omit recording the transaction commit at
- * all. (This test includes the effects of subtransactions, so the
- * presence of committed subxacts need not alone force a write.)
+ * If we haven't been assigned an XID yet, we neither can, nor do we
+ * want to write a COMMIT record.
*/
- if (MyXactMadeXLogEntry || MyXactMadeTempRelUpdate || nrels > 0)
+ if (!markXidCommitted)
{
- TransactionId xid = GetCurrentTransactionId();
- bool madeTCentries;
- bool isAsyncCommit = false;
- XLogRecPtr recptr;
+ /*
+ * We expect that every smgrscheduleunlink is followed by a catalog
+ * update, and hence XID assignment, so we shouldn't get here with
+ * any pending deletes. Use a real test not just an Assert to check
+ * this, since it's a bit fragile.
+ */
+ if (nrels != 0)
+ elog(ERROR, "cannot commit a transaction that deleted files but has no xid");
+
+ /* Can't have child XIDs either; AssignTransactionId enforces this */
+ Assert(nchildren == 0);
+
+ /*
+ * If we didn't create XLOG entries, we're done here; otherwise we
+ * should flush those entries the same as a commit record. (An
+ * example of a possible record that wouldn't cause an XID to be
+ * assigned is a sequence advance record due to nextval() --- we
+ * want to flush that to disk before reporting commit.)
+ */
+ if (XactLastRecEnd.xrecoff == 0)
+ goto cleanup;
+ }
+ else
+ {
+ /*
+ * Begin commit critical section and insert the commit XLOG record.
+ */
+ XLogRecData rdata[3];
+ int lastrdata = 0;
+ xl_xact_commit xlrec;
/* Tell bufmgr and smgr to prepare for commit */
BufmgrCommit();
- START_CRIT_SECTION();
-
/*
- * We only need to log the commit in XLOG if the transaction made any
- * transaction-controlled XLOG entries or will delete files.
+ * Mark ourselves as within our "commit critical section". This
+ * forces any concurrent checkpoint to wait until we've updated
+ * pg_clog. Without this, it is possible for the checkpoint to
+ * set REDO after the XLOG record but fail to flush the pg_clog
+ * update to disk, leading to loss of the transaction commit if
+ * the system crashes a little later.
+ *
+ * Note: we could, but don't bother to, set this flag in
+ * RecordTransactionAbort. That's because loss of a transaction
+ * abort is noncritical; the presumption would be that it aborted,
+ * anyway.
+ *
+ * It's safe to change the inCommit flag of our own backend
+ * without holding the ProcArrayLock, since we're the only one
+ * modifying it. This makes checkpoint's determination of which
+ * xacts are inCommit a bit fuzzy, but it doesn't matter.
*/
- madeTCentries = (MyLastRecPtr.xrecoff != 0);
- if (madeTCentries || nrels > 0)
+ START_CRIT_SECTION();
+ MyProc->inCommit = true;
+
+ SetCurrentTransactionStopTimestamp();
+ xlrec.xact_time = xactStopTimestamp;
+ xlrec.nrels = nrels;
+ xlrec.nsubxacts = nchildren;
+ rdata[0].data = (char *) (&xlrec);
+ rdata[0].len = MinSizeOfXactCommit;
+ rdata[0].buffer = InvalidBuffer;
+ /* dump rels to delete */
+ if (nrels > 0)
{
- XLogRecData rdata[3];
- int lastrdata = 0;
- xl_xact_commit xlrec;
-
- /*
- * Mark ourselves as within our "commit critical section". This
- * forces any concurrent checkpoint to wait until we've updated
- * pg_clog. Without this, it is possible for the checkpoint to
- * set REDO after the XLOG record but fail to flush the pg_clog
- * update to disk, leading to loss of the transaction commit if
- * the system crashes a little later.
- *
- * Note: we could, but don't bother to, set this flag in
- * RecordTransactionAbort. That's because loss of a transaction
- * abort is noncritical; the presumption would be that it aborted,
- * anyway.
- *
- * It's safe to change the inCommit flag of our own backend
- * without holding the ProcArrayLock, since we're the only one
- * modifying it. This makes checkpoint's determination of which
- * xacts are inCommit a bit fuzzy, but it doesn't matter.
- */
- MyProc->inCommit = true;
-
- SetCurrentTransactionStopTimestamp();
- xlrec.xact_time = xactStopTimestamp;
- xlrec.nrels = nrels;
- xlrec.nsubxacts = nchildren;
- rdata[0].data = (char *) (&xlrec);
- rdata[0].len = MinSizeOfXactCommit;
- rdata[0].buffer = InvalidBuffer;
- /* dump rels to delete */
- if (nrels > 0)
- {
- rdata[0].next = &(rdata[1]);
- rdata[1].data = (char *) rels;
- rdata[1].len = nrels * sizeof(RelFileNode);
- rdata[1].buffer = InvalidBuffer;
- lastrdata = 1;
- }
- /* dump committed child Xids */
- if (nchildren > 0)
- {
- rdata[lastrdata].next = &(rdata[2]);
- rdata[2].data = (char *) children;
- rdata[2].len = nchildren * sizeof(TransactionId);
- rdata[2].buffer = InvalidBuffer;
- lastrdata = 2;
- }
- rdata[lastrdata].next = NULL;
-
- recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_COMMIT, rdata);
+ rdata[0].next = &(rdata[1]);
+ rdata[1].data = (char *) rels;
+ rdata[1].len = nrels * sizeof(RelFileNode);
+ rdata[1].buffer = InvalidBuffer;
+ lastrdata = 1;
}
- else
+ /* dump committed child Xids */
+ if (nchildren > 0)
{
- /* Just flush through last record written by me */
- recptr = ProcLastRecEnd;
+ rdata[lastrdata].next = &(rdata[2]);
+ rdata[2].data = (char *) children;
+ rdata[2].len = nchildren * sizeof(TransactionId);
+ rdata[2].buffer = InvalidBuffer;
+ lastrdata = 2;
}
+ rdata[lastrdata].next = NULL;
+
+ (void) XLogInsert(RM_XACT_ID, XLOG_XACT_COMMIT, rdata);
+ }
+ /*
+ * Check if we want to commit asynchronously. If the user has set
+ * synchronous_commit = off, and we're not doing cleanup of any non-temp
+ * rels nor committing any command that wanted to force sync commit, then
+ * we can defer flushing XLOG. (We must not allow asynchronous commit if
+ * there are any non-temp tables to be deleted, because we might delete
+ * the files before the COMMIT record is flushed to disk. We do allow
+ * asynchronous commit if all to-be-deleted tables are temporary though,
+ * since they are lost anyway if we crash.)
+ */
+ if (XactSyncCommit || forceSyncCommit || haveNonTemp)
+ {
/*
- * We must flush our XLOG entries to disk if we made any XLOG entries,
- * whether in or out of transaction control. For example, if we
- * reported a nextval() result to the client, this ensures that any
- * XLOG record generated by nextval will hit the disk before we report
- * the transaction committed.
+ * Synchronous commit case.
*
- * Note: if we generated a commit record above, MyXactMadeXLogEntry
- * will certainly be set now.
+ * Sleep before flush! So we can flush more than one commit
+ * records per single fsync. (The idea is some other backend
+ * may do the XLogFlush while we're sleeping. This needs work
+ * still, because on most Unixen, the minimum select() delay
+ * is 10msec or more, which is way too long.)
+ *
+ * We do not sleep if enableFsync is not turned on, nor if
+ * there are fewer than CommitSiblings other backends with
+ * active transactions.
*/
- if (MyXactMadeXLogEntry)
- {
- /*
- * If the user has set synchronous_commit = off, and we're
- * not doing cleanup of any rels nor committing any command
- * that wanted to force sync commit, then we can defer fsync.
- */
- if (XactSyncCommit || forceSyncCommit || nrels > 0)
- {
- /*
- * Synchronous commit case.
- *
- * Sleep before flush! So we can flush more than one commit
- * records per single fsync. (The idea is some other backend
- * may do the XLogFlush while we're sleeping. This needs work
- * still, because on most Unixen, the minimum select() delay
- * is 10msec or more, which is way too long.)
- *
- * We do not sleep if enableFsync is not turned on, nor if
- * there are fewer than CommitSiblings other backends with
- * active transactions.
- */
- if (CommitDelay > 0 && enableFsync &&
- CountActiveBackends() >= CommitSiblings)
- pg_usleep(CommitDelay);
+ if (CommitDelay > 0 && enableFsync &&
+ CountActiveBackends() >= CommitSiblings)
+ pg_usleep(CommitDelay);
- XLogFlush(recptr);
- }
- else
- {
- /*
- * Asynchronous commit case.
- */
- isAsyncCommit = true;
+ XLogFlush(XactLastRecEnd);
- /*
- * Report the latest async commit LSN, so that
- * the WAL writer knows to flush this commit.
- */
- XLogSetAsyncCommitLSN(recptr);
- }
+ /*
+ * Now we may update the CLOG, if we wrote a COMMIT record above
+ */
+ if (markXidCommitted)
+ {
+ TransactionIdCommit(xid);
+ /* to avoid race conditions, the parent must commit first */
+ TransactionIdCommitTree(nchildren, children);
}
-
+ }
+ else
+ {
/*
- * We must mark the transaction committed in clog if its XID appears
- * either in permanent rels or in local temporary rels. We test this
- * by seeing if we made transaction-controlled entries *OR* local-rel
- * tuple updates. Note that if we made only the latter, we have not
- * emitted an XLOG record for our commit, and so in the event of a
- * crash the clog update might be lost. This is okay because no one
- * else will ever care whether we committed.
+ * Asynchronous commit case.
*
- * The recptr here refers to the last xlog entry by this transaction
- * so is the correct value to use for setting the clog.
+ * Report the latest async commit LSN, so that
+ * the WAL writer knows to flush this commit.
*/
- if (madeTCentries || MyXactMadeTempRelUpdate)
+ XLogSetAsyncCommitLSN(XactLastRecEnd);
+
+ /*
+ * We must not immediately update the CLOG, since we didn't
+ * flush the XLOG. Instead, we store the LSN up to which
+ * the XLOG must be flushed before the CLOG may be updated.
+ */
+ if (markXidCommitted)
{
- if (isAsyncCommit)
- {
- TransactionIdAsyncCommit(xid, recptr);
- /* to avoid race conditions, the parent must commit first */
- TransactionIdAsyncCommitTree(nchildren, children, recptr);
- }
- else
- {
- TransactionIdCommit(xid);
- /* to avoid race conditions, the parent must commit first */
- TransactionIdCommitTree(nchildren, children);
- }
+ TransactionIdAsyncCommit(xid, XactLastRecEnd);
+ /* to avoid race conditions, the parent must commit first */
+ TransactionIdAsyncCommitTree(nchildren, children, XactLastRecEnd);
}
+ }
- /* Checkpoint can proceed now */
+ /*
+ * If we entered a commit critical section, leave it now, and
+ * let checkpoints proceed.
+ */
+ if (markXidCommitted)
+ {
MyProc->inCommit = false;
-
END_CRIT_SECTION();
}
- /* Break the chain of back-links in the XLOG records I output */
- MyLastRecPtr.xrecoff = 0;
- MyXactMadeXLogEntry = false;
- MyXactMadeTempRelUpdate = false;
+ /* Reset XactLastRecEnd until the next transaction writes something */
+ XactLastRecEnd.xrecoff = 0;
- /* And clean up local data */
+cleanup:
+ /* Clean up local data */
if (rels)
pfree(rels);
if (children)
static void
RecordSubTransactionCommit(void)
{
+ TransactionId xid = GetCurrentTransactionIdIfAny();
+
/*
* We do not log the subcommit in XLOG; it doesn't matter until the
* top-level transaction commits.
*
- * We must mark the subtransaction subcommitted in clog if its XID appears
- * either in permanent rels or in local temporary rels. We test this by
- * seeing if we made transaction-controlled entries *OR* local-rel tuple
- * updates. (The test here actually covers the entire transaction tree so
- * far, so it may mark subtransactions that don't really need it, but it's
- * probably not worth being tenser. Note that if a prior subtransaction
- * dirtied these variables, then RecordTransactionCommit will have to do
- * the full pushup anyway...)
+ * We must mark the subtransaction subcommitted in the CLOG if
+ * it had a valid XID assigned. If it did not, nobody else will
+ * ever know about the existence of this subxact. We don't
+ * have to deal with deletions scheduled for on-commit here, since
+ * they'll be reassigned to our parent (who might still abort).
*/
- if (MyLastRecPtr.xrecoff != 0 || MyXactMadeTempRelUpdate)
+ if (TransactionIdIsValid(xid))
{
- TransactionId xid = GetCurrentTransactionId();
-
/* XXX does this really need to be a critical section? */
START_CRIT_SECTION();
* RecordTransactionAbort
*/
static void
-RecordTransactionAbort(void)
+RecordTransactionAbort(bool isSubXact)
{
+ TransactionId xid = GetCurrentTransactionIdIfAny();
int nrels;
RelFileNode *rels;
int nchildren;
TransactionId *children;
-
- /* Get data needed for abort record */
- nrels = smgrGetPendingDeletes(false, &rels);
- nchildren = xactGetCommittedChildren(&children);
+ XLogRecData rdata[3];
+ int lastrdata = 0;
+ xl_xact_abort xlrec;
/*
- * If we made neither any transaction-controlled XLOG entries nor any
- * temp-rel updates, and are not going to delete any files, we can omit
- * recording the transaction abort at all. No one will ever care that it
- * aborted. (These tests cover our whole transaction tree.)
+ * If we haven't been assigned an XID, nobody will care whether we
+ * aborted or not. Hence, we're done in that case. It does not matter
+ * if we have rels to delete (note that this routine is not responsible
+ * for actually deleting 'em). We cannot have any child XIDs, either.
*/
- if (MyLastRecPtr.xrecoff != 0 || MyXactMadeTempRelUpdate || nrels > 0)
+ if (!TransactionIdIsValid(xid))
{
- TransactionId xid = GetCurrentTransactionId();
+ /* Reset XactLastRecEnd until the next transaction writes something */
+ if (!isSubXact)
+ XactLastRecEnd.xrecoff = 0;
+ return;
+ }
- /*
- * Catch the scenario where we aborted partway through
- * RecordTransactionCommit ...
- */
- if (TransactionIdDidCommit(xid))
- elog(PANIC, "cannot abort transaction %u, it was already committed", xid);
+ /*
+ * We have a valid XID, so we should write an ABORT record for it.
+ *
+ * We do not flush XLOG to disk here, since the default assumption after a
+ * crash would be that we aborted, anyway. For the same reason, we don't
+ * need to worry about interlocking against checkpoint start.
+ */
- START_CRIT_SECTION();
+ /*
+ * Check that we haven't aborted halfway through RecordTransactionCommit.
+ */
+ if (TransactionIdDidCommit(xid))
+ elog(PANIC, "cannot abort transaction %u, it was already committed",
+ xid);
- /*
- * We only need to log the abort in XLOG if the transaction made any
- * transaction-controlled XLOG entries or will delete files. (If it
- * made no transaction-controlled XLOG entries, its XID appears
- * nowhere in permanent storage, so no one else will ever care if it
- * committed.)
- *
- * We do not flush XLOG to disk unless deleting files, since the
- * default assumption after a crash would be that we aborted, anyway.
- * For the same reason, we don't need to worry about interlocking
- * against checkpoint start.
- */
- if (MyLastRecPtr.xrecoff != 0 || nrels > 0)
- {
- XLogRecData rdata[3];
- int lastrdata = 0;
- xl_xact_abort xlrec;
- XLogRecPtr recptr;
-
- SetCurrentTransactionStopTimestamp();
- xlrec.xact_time = xactStopTimestamp;
- xlrec.nrels = nrels;
- xlrec.nsubxacts = nchildren;
- rdata[0].data = (char *) (&xlrec);
- rdata[0].len = MinSizeOfXactAbort;
- rdata[0].buffer = InvalidBuffer;
- /* dump rels to delete */
- if (nrels > 0)
- {
- rdata[0].next = &(rdata[1]);
- rdata[1].data = (char *) rels;
- rdata[1].len = nrels * sizeof(RelFileNode);
- rdata[1].buffer = InvalidBuffer;
- lastrdata = 1;
- }
- /* dump committed child Xids */
- if (nchildren > 0)
- {
- rdata[lastrdata].next = &(rdata[2]);
- rdata[2].data = (char *) children;
- rdata[2].len = nchildren * sizeof(TransactionId);
- rdata[2].buffer = InvalidBuffer;
- lastrdata = 2;
- }
- rdata[lastrdata].next = NULL;
+ /* Fetch the data we need for the abort record */
+ nrels = smgrGetPendingDeletes(false, &rels, NULL);
+ nchildren = xactGetCommittedChildren(&children);
- recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_ABORT, rdata);
+ /* XXX do we really need a critical section here? */
+ START_CRIT_SECTION();
- /* Must flush if we are deleting files... */
- if (nrels > 0)
- XLogFlush(recptr);
- }
+ /* Write the ABORT record */
+ if (isSubXact)
+ xlrec.xact_time = GetCurrentTimestamp();
+ else
+ {
+ SetCurrentTransactionStopTimestamp();
+ xlrec.xact_time = xactStopTimestamp;
+ }
+ xlrec.nrels = nrels;
+ xlrec.nsubxacts = nchildren;
+ rdata[0].data = (char *) (&xlrec);
+ rdata[0].len = MinSizeOfXactAbort;
+ rdata[0].buffer = InvalidBuffer;
+ /* dump rels to delete */
+ if (nrels > 0)
+ {
+ rdata[0].next = &(rdata[1]);
+ rdata[1].data = (char *) rels;
+ rdata[1].len = nrels * sizeof(RelFileNode);
+ rdata[1].buffer = InvalidBuffer;
+ lastrdata = 1;
+ }
+ /* dump committed child Xids */
+ if (nchildren > 0)
+ {
+ rdata[lastrdata].next = &(rdata[2]);
+ rdata[2].data = (char *) children;
+ rdata[2].len = nchildren * sizeof(TransactionId);
+ rdata[2].buffer = InvalidBuffer;
+ lastrdata = 2;
+ }
+ rdata[lastrdata].next = NULL;
- /*
- * Mark the transaction aborted in clog. This is not absolutely
- * necessary but we may as well do it while we are here.
- *
- * The ordering here isn't critical but it seems best to mark the
- * parent first. This assures an atomic transition of all the
- * subtransactions to aborted state from the point of view of
- * concurrent TransactionIdDidAbort calls.
- */
- TransactionIdAbort(xid);
- TransactionIdAbortTree(nchildren, children);
+ (void) XLogInsert(RM_XACT_ID, XLOG_XACT_ABORT, rdata);
- END_CRIT_SECTION();
- }
+ /*
+ * Mark the transaction aborted in clog. This is not absolutely necessary
+ * but we may as well do it while we are here; also, in the subxact case
+ * it is helpful because XactLockTableWait makes use of it to avoid
+ * waiting for already-aborted subtransactions. It is OK to do it without
+ * having flushed the ABORT record to disk, because in event of a crash
+ * we'd be assumed to have aborted anyway.
+ *
+ * The ordering here isn't critical but it seems best to mark the
+ * parent first. This assures an atomic transition of all the
+ * subtransactions to aborted state from the point of view of
+ * concurrent TransactionIdDidAbort calls.
+ */
+ TransactionIdAbort(xid);
+ TransactionIdAbortTree(nchildren, children);
- /* Break the chain of back-links in the XLOG records I output */
- MyLastRecPtr.xrecoff = 0;
- MyXactMadeXLogEntry = false;
- MyXactMadeTempRelUpdate = false;
+ END_CRIT_SECTION();
+
+ /*
+ * If we're aborting a subtransaction, we can immediately remove failed
+ * XIDs from PGPROC's cache of running child XIDs. We do that here for
+ * subxacts, because we already have the child XID array at hand. For
+ * main xacts, the equivalent happens just after this function returns.
+ */
+ if (isSubXact)
+ XidCacheRemoveRunningXids(xid, nchildren, children);
+
+ /* Reset XactLastRecEnd until the next transaction writes something */
+ if (!isSubXact)
+ XactLastRecEnd.xrecoff = 0;
/* And clean up local data */
if (rels)
s->childXids = NIL;
}
-/*
- * RecordSubTransactionAbort
- */
-static void
-RecordSubTransactionAbort(void)
-{
- int nrels;
- RelFileNode *rels;
- TransactionId xid = GetCurrentTransactionId();
- int nchildren;
- TransactionId *children;
-
- /* Get data needed for abort record */
- nrels = smgrGetPendingDeletes(false, &rels);
- nchildren = xactGetCommittedChildren(&children);
-
- /*
- * If we made neither any transaction-controlled XLOG entries nor any
- * temp-rel updates, and are not going to delete any files, we can omit
- * recording the transaction abort at all. No one will ever care that it
- * aborted. (These tests cover our whole transaction tree, and therefore
- * may mark subxacts that don't really need it, but it's probably not
- * worth being tenser.)
- *
- * In this case we needn't worry about marking subcommitted children as
- * aborted, because they didn't mark themselves as subcommitted in the
- * first place; see the optimization in RecordSubTransactionCommit.
- */
- if (MyLastRecPtr.xrecoff != 0 || MyXactMadeTempRelUpdate || nrels > 0)
- {
- START_CRIT_SECTION();
-
- /*
- * We only need to log the abort in XLOG if the transaction made any
- * transaction-controlled XLOG entries or will delete files.
- */
- if (MyLastRecPtr.xrecoff != 0 || nrels > 0)
- {
- XLogRecData rdata[3];
- int lastrdata = 0;
- xl_xact_abort xlrec;
- XLogRecPtr recptr;
-
- xlrec.xact_time = GetCurrentTimestamp();
- xlrec.nrels = nrels;
- xlrec.nsubxacts = nchildren;
- rdata[0].data = (char *) (&xlrec);
- rdata[0].len = MinSizeOfXactAbort;
- rdata[0].buffer = InvalidBuffer;
- /* dump rels to delete */
- if (nrels > 0)
- {
- rdata[0].next = &(rdata[1]);
- rdata[1].data = (char *) rels;
- rdata[1].len = nrels * sizeof(RelFileNode);
- rdata[1].buffer = InvalidBuffer;
- lastrdata = 1;
- }
- /* dump committed child Xids */
- if (nchildren > 0)
- {
- rdata[lastrdata].next = &(rdata[2]);
- rdata[2].data = (char *) children;
- rdata[2].len = nchildren * sizeof(TransactionId);
- rdata[2].buffer = InvalidBuffer;
- lastrdata = 2;
- }
- rdata[lastrdata].next = NULL;
-
- recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_ABORT, rdata);
-
- /* Must flush if we are deleting files... */
- if (nrels > 0)
- XLogFlush(recptr);
- }
-
- /*
- * Mark the transaction aborted in clog. This is not absolutely
- * necessary but XactLockTableWait makes use of it to avoid waiting
- * for already-aborted subtransactions.
- */
- TransactionIdAbort(xid);
- TransactionIdAbortTree(nchildren, children);
-
- END_CRIT_SECTION();
- }
-
- /*
- * We can immediately remove failed XIDs from PGPROC's cache of running
- * child XIDs. It's easiest to do it here while we have the child XID
- * array at hand, even though in the main-transaction case the equivalent
- * work happens just after return from RecordTransactionAbort.
- */
- XidCacheRemoveRunningXids(xid, nchildren, children);
-
- /* And clean up local data */
- if (rels)
- pfree(rels);
- if (children)
- pfree(children);
-}
-
/* ----------------------------------------------------------------
* CleanupTransaction stuff
* ----------------------------------------------------------------
StartTransaction(void)
{
TransactionState s;
+ VirtualTransactionId vxid;
/*
* Let's just make sure the state stack is empty
AtStart_ResourceOwner();
/*
- * generate a new transaction id
+ * Assign a new LocalTransactionId, and combine it with the backendId to
+ * form a virtual transaction id.
+ */
+ vxid.backendId = MyBackendId;
+ vxid.localTransactionId = GetNextLocalTransactionId();
+
+ /*
+ * Lock the virtual transaction id before we announce it in the proc array
*/
- s->transactionId = GetNewTransactionId(false);
+ VirtualXactLockTableInsert(vxid);
- XactLockTableInsert(s->transactionId);
+ /*
+ * Advertise it in the proc array. We assume assignment of
+ * LocalTransactionID is atomic, and the backendId should be set already.
+ */
+ Assert(MyProc->backendId == vxid.backendId);
+ MyProc->lxid = vxid.localTransactionId;
- PG_TRACE1(transaction__start, s->transactionId);
+ PG_TRACE1(transaction__start, vxid.localTransactionId);
/*
* set transaction_timestamp() (a/k/a now()). We want this to be the same
*/
if (MyProc != NULL)
{
- /* Lock ProcArrayLock because that's what GetSnapshotData uses. */
+ /*
+ * Lock ProcArrayLock because that's what GetSnapshotData uses.
+ * You might assume that we can skip this step if we had no
+ * transaction id assigned, because the failure case outlined
+ * in GetSnapshotData cannot happen in that case. This is true,
+ * but we *still* need the lock guarantee that two concurrent
+ * computations of the *oldest* xmin will get the same result.
+ */
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
MyProc->xid = InvalidTransactionId;
+ MyProc->lxid = InvalidLocalTransactionId;
MyProc->xmin = InvalidTransactionId;
MyProc->inVacuum = false; /* must be cleared with xid/xmin */
* Now we clean up backend-internal state and release internal resources.
*/
- /* Break the chain of back-links in the XLOG records I output */
- MyLastRecPtr.xrecoff = 0;
- MyXactMadeXLogEntry = false;
- MyXactMadeTempRelUpdate = false;
+ /* Reset XactLastRecEnd until the next transaction writes something */
+ XactLastRecEnd.xrecoff = 0;
/*
* Let others know about no transaction in progress by me. This has to be
* someone may think it is unlocked and recyclable.
*/
- /* Lock ProcArrayLock because that's what GetSnapshotData uses. */
+ /*
+ * Lock ProcArrayLock because that's what GetSnapshotData uses.
+ * You might assume that we can skip this step if we have no
+ * transaction id assigned, because the failure case outlined
+ * in GetSnapshotData cannot happen in that case. This is true,
+ * but we *still* need the lock guarantee that two concurrent
+ * computations of the *oldest* xmin will get the same result.
+ */
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
MyProc->xid = InvalidTransactionId;
+ MyProc->lxid = InvalidLocalTransactionId;
MyProc->xmin = InvalidTransactionId;
MyProc->inVacuum = false; /* must be cleared with xid/xmin */
* Advertise the fact that we aborted in pg_clog (assuming that we got as
* far as assigning an XID to advertise).
*/
- if (TransactionIdIsValid(s->transactionId))
- RecordTransactionAbort();
+ RecordTransactionAbort(false);
/*
* Let others know about no transaction in progress by me. Note that this
*/
if (MyProc != NULL)
{
- /* Lock ProcArrayLock because that's what GetSnapshotData uses. */
+ /*
+ * Lock ProcArrayLock because that's what GetSnapshotData uses.
+ * You might assume that we can skip this step if we have no
+ * transaction id assigned, because the failure case outlined
+ * in GetSnapshotData cannot happen in that case. This is true,
+ * but we *still* need the lock guarantee that two concurrent
+ * computations of the *oldest* xmin will get the same result.
+ */
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
MyProc->xid = InvalidTransactionId;
+ MyProc->lxid = InvalidLocalTransactionId;
MyProc->xmin = InvalidTransactionId;
MyProc->inVacuum = false; /* must be cleared with xid/xmin */
MyProc->inCommit = false; /* be sure this gets cleared */
CommandCounterIncrement();
/* Mark subtransaction as subcommitted */
- if (TransactionIdIsValid(s->transactionId))
- {
- RecordSubTransactionCommit();
- AtSubCommit_childXids();
- }
+ RecordSubTransactionCommit();
/* Post-commit cleanup */
+ if (TransactionIdIsValid(s->transactionId))
+ AtSubCommit_childXids();
AfterTriggerEndSubXact(true);
AtSubCommit_Portals(s->subTransactionId,
s->parent->subTransactionId,
s->parent->subTransactionId);
/* Advertise the fact that we aborted in pg_clog. */
+ RecordTransactionAbort(true);
+
+ /* Post-abort cleanup */
if (TransactionIdIsValid(s->transactionId))
- {
- RecordSubTransactionAbort();
AtSubAbort_childXids();
- }
- /* Post-abort cleanup */
CallSubXactCallbacks(SUBXACT_EVENT_ABORT_SUB, s->subTransactionId,
s->parent->subTransactionId);
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.279 2007/08/28 23:17:47 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.280 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
static List *expectedTLIs;
static TimeLineID curFileTLI;
-/*
- * MyLastRecPtr points to the start of the last XLOG record inserted by the
- * current transaction. If MyLastRecPtr.xrecoff == 0, then the current
- * xact hasn't yet inserted any transaction-controlled XLOG records.
- *
- * Note that XLOG records inserted outside transaction control are not
- * reflected into MyLastRecPtr. They do, however, cause MyXactMadeXLogEntry
- * to be set true. The latter can be used to test whether the current xact
- * made any loggable changes (including out-of-xact changes, such as
- * sequence updates).
- *
- * When we insert/update/delete a tuple in a temporary relation, we do not
- * make any XLOG record, since we don't care about recovering the state of
- * the temp rel after a crash. However, we will still need to remember
- * whether our transaction committed or aborted in that case. So, we must
- * set MyXactMadeTempRelUpdate true to indicate that the XID will be of
- * interest later.
- */
-XLogRecPtr MyLastRecPtr = {0, 0};
-
-bool MyXactMadeXLogEntry = false;
-
-bool MyXactMadeTempRelUpdate = false;
-
/*
* ProcLastRecPtr points to the start of the last XLOG record inserted by the
- * current backend. It is updated for all inserts, transaction-controlled
- * or not. ProcLastRecEnd is similar but points to end+1 of last record.
+ * current backend. It is updated for all inserts. XactLastRecEnd points to
+ * end+1 of the last record, and is reset when we end a top-level transaction,
+ * or start a new one; so it can be used to tell if the current transaction has
+ * created any XLOG records.
*/
static XLogRecPtr ProcLastRecPtr = {0, 0};
-XLogRecPtr ProcLastRecEnd = {0, 0};
+XLogRecPtr XactLastRecEnd = {0, 0};
/*
* RedoRecPtr is this backend's local copy of the REDO record pointer
bool updrqst;
bool doPageWrites;
bool isLogSwitch = (rmid == RM_XLOG_ID && info == XLOG_SWITCH);
- bool no_tran = (rmid == RM_XLOG_ID);
+ /* info's high bits are reserved for use by me */
if (info & XLR_INFO_MASK)
- {
- if ((info & XLR_INFO_MASK) != XLOG_NO_TRAN)
- elog(PANIC, "invalid xlog info mask %02X", (info & XLR_INFO_MASK));
- no_tran = true;
- info &= ~XLR_INFO_MASK;
- }
+ elog(PANIC, "invalid xlog info mask %02X", info);
/*
* In bootstrap mode, we don't actually log anything but XLOG resources;
#endif
/* Record begin of record in appropriate places */
- if (!no_tran)
- MyLastRecPtr = RecPtr;
ProcLastRecPtr = RecPtr;
Insert->PrevRecord = RecPtr;
- MyXactMadeXLogEntry = true;
Insert->currpos += SizeOfXLogRecord;
freespace -= SizeOfXLogRecord;
SpinLockRelease(&xlogctl->info_lck);
}
- ProcLastRecEnd = RecPtr;
+ XactLastRecEnd = RecPtr;
END_CRIT_SECTION();
*
* Copyright (c) 1996-2007, PostgreSQL Global Development Group
*
- * $PostgreSQL: pgsql/src/backend/catalog/system_views.sql,v 1.41 2007/08/25 17:47:44 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/catalog/system_views.sql,v 1.42 2007/09/05 18:10:47 tgl Exp $
*/
CREATE VIEW pg_roles AS
SELECT *
FROM pg_lock_status() AS L
(locktype text, database oid, relation oid, page int4, tuple int2,
- transactionid xid, classid oid, objid oid, objsubid int2,
- transaction xid, pid int4, mode text, granted boolean);
+ virtualxid text, transactionid xid, classid oid, objid oid, objsubid int2,
+ virtualtransaction text, pid int4, mode text, granted boolean);
CREATE VIEW pg_cursors AS
SELECT C.name, C.statement, C.is_holdable, C.is_binary,
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/indexcmds.c,v 1.162 2007/08/25 19:08:19 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/indexcmds.c,v 1.163 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "parser/parse_expr.h"
#include "parser/parse_func.h"
#include "parser/parsetree.h"
+#include "storage/procarray.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
int16 *coloptions;
IndexInfo *indexInfo;
int numberOfAttributes;
- List *old_xact_list;
- ListCell *lc;
- uint32 ixcnt;
+ VirtualTransactionId *old_lockholders;
+ VirtualTransactionId *old_snapshots;
LockRelId heaprelid;
LOCKTAG heaplocktag;
Snapshot snapshot;
* xacts that open the table for writing after this point; they will see
* the new index when they open it.
*
+ * Note: the reason we use actual lock acquisition here, rather than
+ * just checking the ProcArray and sleeping, is that deadlock is possible
+ * if one of the transactions in question is blocked trying to acquire
+ * an exclusive lock on our table. The lock code will detect deadlock
+ * and error out properly.
+ *
* Note: GetLockConflicts() never reports our own xid, hence we need not
- * check for that.
+ * check for that. Also, prepared xacts are not reported, which is
+ * fine since they certainly aren't going to do anything more.
*/
SET_LOCKTAG_RELATION(heaplocktag, heaprelid.dbId, heaprelid.relId);
- old_xact_list = GetLockConflicts(&heaplocktag, ShareLock);
+ old_lockholders = GetLockConflicts(&heaplocktag, ShareLock);
- foreach(lc, old_xact_list)
+ while (VirtualTransactionIdIsValid(*old_lockholders))
{
- TransactionId xid = lfirst_xid(lc);
-
- XactLockTableWait(xid);
+ VirtualXactLockTableWait(*old_lockholders);
+ old_lockholders++;
}
/*
* Now take the "reference snapshot" that will be used by validate_index()
- * to filter candidate tuples. All other transactions running at this
- * time will have to be out-waited before we can commit, because we can't
- * guarantee that tuples deleted just before this will be in the index.
+ * to filter candidate tuples. Beware! There might be still snapshots
+ * in use that treat some transaction as in-progress that our reference
+ * snapshot treats as committed. If such a recently-committed transaction
+ * deleted tuples in the table, we will not include them in the index; yet
+ * those transactions which see the deleting one as still-in-progress will
+ * expect them to be there once we mark the index as valid.
+ *
+ * We solve this by waiting for all endangered transactions to exit before
+ * we mark the index as valid.
*
* We also set ActiveSnapshot to this snap, since functions in indexes may
* need a snapshot.
* The index is now valid in the sense that it contains all currently
* interesting tuples. But since it might not contain tuples deleted just
* before the reference snap was taken, we have to wait out any
- * transactions older than the reference snap. We can do this by waiting
- * for each xact explicitly listed in the snap.
+ * transactions that might have older snapshots. Obtain a list of
+ * VXIDs of such transactions, and wait for them individually.
*
- * Note: GetSnapshotData() never stores our own xid into a snap, hence we
- * need not check for that.
+ * We can exclude any running transactions that have xmin >= the xmax of
+ * our reference snapshot, since they are clearly not interested in any
+ * missing older tuples. Also, GetCurrentVirtualXIDs never reports our
+ * own vxid, so we need not check for that.
*/
- for (ixcnt = 0; ixcnt < snapshot->xcnt; ixcnt++)
- XactLockTableWait(snapshot->xip[ixcnt]);
+ old_snapshots = GetCurrentVirtualXIDs(ActiveSnapshot->xmax);
+
+ while (VirtualTransactionIdIsValid(*old_snapshots))
+ {
+ VirtualXactLockTableWait(*old_snapshots);
+ old_snapshots++;
+ }
/*
* Index can now be marked valid -- update its pg_index entry
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.143 2007/02/01 19:10:26 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.144 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "commands/tablecmds.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
+#include "storage/proc.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
{
struct SeqTableData *next; /* link to next SeqTable object */
Oid relid; /* pg_class OID of this sequence */
- TransactionId xid; /* xact in which we last did a seq op */
+ LocalTransactionId lxid; /* xact in which we last did a seq op */
int64 last; /* value last returned by nextval */
int64 cached; /* last value already cached for nextval */
/* if last != cached, we have not used up all the cached values */
rdata[1].buffer = InvalidBuffer;
rdata[1].next = NULL;
- recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG | XLOG_NO_TRAN, rdata);
+ recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
rdata[1].buffer = InvalidBuffer;
rdata[1].next = NULL;
- recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG | XLOG_NO_TRAN, rdata);
+ recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
rdata[1].buffer = InvalidBuffer;
rdata[1].next = NULL;
- recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG | XLOG_NO_TRAN, rdata);
+ recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
rdata[1].buffer = InvalidBuffer;
rdata[1].next = NULL;
- recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG | XLOG_NO_TRAN, rdata);
+ recptr = XLogInsert(RM_SEQ_ID, XLOG_SEQ_LOG, rdata);
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
static Relation
open_share_lock(SeqTable seq)
{
- TransactionId thisxid = GetTopTransactionId();
+ LocalTransactionId thislxid = MyProc->lxid;
/* Get the lock if not already held in this xact */
- if (seq->xid != thisxid)
+ if (seq->lxid != thislxid)
{
ResourceOwner currentOwner;
CurrentResourceOwner = currentOwner;
/* Flag that we have a lock in the current xact */
- seq->xid = thisxid;
+ seq->lxid = thislxid;
}
/* We now know we have AccessShareLock, and can safely open the rel */
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory")));
elm->relid = relid;
- elm->xid = InvalidTransactionId;
+ elm->lxid = InvalidLocalTransactionId;
/* increment is set to 0 until we do read_info (see currval) */
elm->last = elm->cached = elm->increment = 0;
elm->next = seqtab;
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.355 2007/08/13 19:08:26 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.356 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
- else
- {
- /*
- * No XLOG record, but still need to flag that XID exists on
- * disk
- */
- MyXactMadeTempRelUpdate = true;
- }
END_CRIT_SECTION();
PageSetLSN(dst_page, recptr);
PageSetTLI(dst_page, ThisTimeLineID);
}
- else
- {
- /*
- * No XLOG record, but still need to flag that XID exists on disk
- */
- MyXactMadeTempRelUpdate = true;
- }
END_CRIT_SECTION();
PageSetLSN(dst_page, recptr);
PageSetTLI(dst_page, ThisTimeLineID);
}
- else
- {
- /*
- * No XLOG record, but still need to flag that XID exists on disk
- */
- MyXactMadeTempRelUpdate = true;
- }
END_CRIT_SECTION();
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
- else
- {
- /* No XLOG record, but still need to flag that XID exists on disk */
- MyXactMadeTempRelUpdate = true;
- }
END_CRIT_SECTION();
}
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.90 2007/05/30 20:11:57 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.91 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
PageSetLSN(page, recptr);
PageSetTLI(page, ThisTimeLineID);
}
- else
- {
- /* No XLOG record, but still need to flag that XID exists on disk */
- MyXactMadeTempRelUpdate = true;
- }
END_CRIT_SECTION();
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.28 2007/07/01 02:22:23 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.29 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
* This is also used to determine where to truncate pg_subtrans. allDbs
* must be TRUE for that case, and ignoreVacuum FALSE.
*
- * Note: we include the currently running xids in the set of considered xids.
+ * Note: we include all currently running xids in the set of considered xids.
* This ensures that if a just-started xact has not yet set its snapshot,
* when it does set the snapshot it cannot set xmin less than what we compute.
*/
int index;
/*
- * Normally we start the min() calculation with our own XID. But if
- * called by checkpointer, we will not be inside a transaction, so use
- * next XID as starting point for min() calculation. (Note that if there
- * are no xacts running at all, that will be the subtrans truncation
- * point!)
+ * We need to initialize the MIN() calculation with something.
+ * ReadNewTransactionId() is guaranteed to work, but is relatively
+ * expensive due to locking; so first we try a couple of shortcuts.
+ * If we have a valid xmin in our own PGPROC entry, that will do;
+ * or if we have assigned ourselves an XID, that will do.
*/
- result = GetTopTransactionId();
+ result = MyProc ? MyProc->xmin : InvalidTransactionId;
if (!TransactionIdIsValid(result))
- result = ReadNewTransactionId();
+ {
+ result = GetTopTransactionIdIfAny();
+ if (!TransactionIdIsValid(result))
+ result = ReadNewTransactionId();
+ }
LWLockAcquire(ProcArrayLock, LW_SHARED);
/* Fetch xid just once - see GetNewTransactionId */
TransactionId xid = proc->xid;
- if (TransactionIdIsNormal(xid))
- {
- /* First consider the transaction own's Xid */
- if (TransactionIdPrecedes(xid, result))
- result = xid;
-
- /*
- * Also consider the transaction's Xmin, if set.
- *
- * We must check both Xid and Xmin because there is a window
- * where an xact's Xid is set but Xmin isn't yet.
- */
- xid = proc->xmin;
- if (TransactionIdIsNormal(xid))
- if (TransactionIdPrecedes(xid, result))
- result = xid;
- }
+ /* First consider the transaction's own Xid, if any */
+ if (TransactionIdIsNormal(xid) &&
+ TransactionIdPrecedes(xid, result))
+ result = xid;
+
+ /*
+ * Also consider the transaction's Xmin, if set.
+ *
+ * We must check both Xid and Xmin because a transaction might
+ * have an Xmin but not (yet) an Xid; conversely, if it has
+ * an Xid, that could determine some not-yet-set Xmin.
+ */
+ xid = proc->xmin; /* Fetch just once */
+ if (TransactionIdIsNormal(xid) &&
+ TransactionIdPrecedes(xid, result))
+ result = xid;
}
}
errmsg("out of memory")));
}
- globalxmin = xmin = GetTopTransactionId();
-
/*
* It is sufficient to get shared lock on ProcArrayLock, even if we are
* computing a serializable snapshot and therefore will be setting
* discussion just below). So it doesn't matter whether another backend
* concurrently doing GetSnapshotData or GetOldestXmin sees our xmin as
* set or not; he'd compute the same xmin for himself either way.
+ * (We are assuming here that xmin can be set and read atomically,
+ * just like xid.)
+ *
+ * There is a corner case in which the above argument doesn't work: if
+ * there isn't any oldest xact, ie, all xids in the array are invalid.
+ * In that case we will compute xmin as the result of ReadNewTransactionId,
+ * and since GetNewTransactionId doesn't take the ProcArrayLock, it's not
+ * so obvious that two backends with overlapping shared locks will get
+ * the same answer. But GetNewTransactionId is required to store the XID
+ * it assigned into the ProcArray before releasing XidGenLock. Therefore
+ * the backend that did ReadNewTransactionId later will see that XID in
+ * the array, and will compute the same xmin as the earlier one that saw
+ * no XIDs in the array.
*/
LWLockAcquire(ProcArrayLock, LW_SHARED);
xmax = ReadNewTransactionId();
+ /* initialize xmin calculation with xmax */
+ globalxmin = xmin = xmax;
+
/*
* Spin over procArray checking xid, xmin, and subxids. The goal is
* to gather all active xids, find the lowest xmin, and try to record
for (index = 0; index < arrayP->numProcs; index++)
{
PGPROC *proc = arrayP->procs[index];
+ TransactionId xid;
+
+ /* Ignore procs running LAZY VACUUM */
+ if (proc->inVacuum)
+ continue;
+
+ /* Update globalxmin to be the smallest valid xmin */
+ xid = proc->xmin; /* fetch just once */
+ if (TransactionIdIsNormal(xid) &&
+ TransactionIdPrecedes(xid, globalxmin))
+ globalxmin = xid;
/* Fetch xid just once - see GetNewTransactionId */
- TransactionId xid = proc->xid;
+ xid = proc->xid;
/*
- * Ignore my own proc (dealt with my xid above), procs not running a
- * transaction, xacts started since we read the next transaction ID,
- * and xacts executing LAZY VACUUM. There's no need to store XIDs
- * above what we got from ReadNewTransactionId, since we'll treat them
- * as running anyway. We also assume that such xacts can't compute an
- * xmin older than ours, so they needn't be considered in computing
- * globalxmin.
+ * If the transaction has been assigned an xid < xmax we add it to the
+ * snapshot, and update xmin if necessary. There's no need to store
+ * XIDs above what we got from ReadNewTransactionId, since we'll treat
+ * them as running anyway. We don't bother to examine their subxids
+ * either.
+ *
+ * We don't include our own XID (if any) in the snapshot, but we must
+ * include it into xmin.
*/
- if (proc == MyProc ||
- !TransactionIdIsNormal(xid) ||
- TransactionIdFollowsOrEquals(xid, xmax) ||
- proc->inVacuum)
- continue;
-
- if (TransactionIdPrecedes(xid, xmin))
- xmin = xid;
- snapshot->xip[count++] = xid;
-
- /* Update globalxmin to be the smallest valid xmin */
- xid = proc->xmin;
if (TransactionIdIsNormal(xid))
- if (TransactionIdPrecedes(xid, globalxmin))
- globalxmin = xid;
+ {
+ if (TransactionIdFollowsOrEquals(xid, xmax))
+ continue;
+ if (proc != MyProc)
+ snapshot->xip[count++] = xid;
+ if (TransactionIdPrecedes(xid, xmin))
+ xmin = xid;
+ }
/*
* Save subtransaction XIDs if possible (if we've already overflowed,
* remove any. Hence it's important to fetch nxids just once. Should
* be safe to use memcpy, though. (We needn't worry about missing any
* xids added concurrently, because they must postdate xmax.)
+ *
+ * Again, our own XIDs are not included in the snapshot.
*/
- if (subcount >= 0)
+ if (subcount >= 0 && proc != MyProc)
{
if (proc->subxids.overflowed)
subcount = -1; /* overflowed */
*
* Only main transaction Ids are considered. This function is mainly
* useful for determining what backend owns a lock.
+ *
+ * Beware that not every xact has an XID assigned. However, as long as you
+ * only call this using an XID found on disk, you're safe.
*/
int
BackendXidGetPid(TransactionId xid)
return (BackendPidGetProc(pid) != NULL);
}
+
+/*
+ * GetCurrentVirtualXIDs -- returns an array of currently active VXIDs.
+ *
+ * The array is palloc'd and is terminated with an invalid VXID.
+ *
+ * If limitXmin is not InvalidTransactionId, we skip any backends
+ * with xmin >= limitXmin. Also, our own process is always skipped.
+ */
+VirtualTransactionId *
+GetCurrentVirtualXIDs(TransactionId limitXmin)
+{
+ VirtualTransactionId *vxids;
+ ProcArrayStruct *arrayP = procArray;
+ int count = 0;
+ int index;
+
+ /* allocate result space with room for a terminator */
+ vxids = (VirtualTransactionId *)
+ palloc(sizeof(VirtualTransactionId) * (arrayP->maxProcs + 1));
+
+ LWLockAcquire(ProcArrayLock, LW_SHARED);
+
+ for (index = 0; index < arrayP->numProcs; index++)
+ {
+ PGPROC *proc = arrayP->procs[index];
+ /* Fetch xmin just once - might change on us? */
+ TransactionId pxmin = proc->xmin;
+
+ if (proc == MyProc)
+ continue;
+
+ /*
+ * Note that InvalidTransactionId precedes all other XIDs, so a
+ * proc that hasn't set xmin yet will always be included.
+ */
+ if (!TransactionIdIsValid(limitXmin) ||
+ TransactionIdPrecedes(pxmin, limitXmin))
+ {
+ VirtualTransactionId vxid;
+
+ GET_VXID_FROM_PGPROC(vxid, *proc);
+ if (VirtualTransactionIdIsValid(vxid))
+ vxids[count++] = vxid;
+ }
+ }
+
+ LWLockRelease(ProcArrayLock);
+
+ /* add the terminator */
+ vxids[count].backendId = InvalidBackendId;
+ vxids[count].localTransactionId = InvalidLocalTransactionId;
+
+ return vxids;
+}
+
+
/*
* CountActiveBackends --- count backends (other than myself) that are in
* active transactions. This is used as a heuristic to decide if
if (proc->pid == 0)
continue; /* do not count prepared xacts */
if (proc->xid == InvalidTransactionId)
- continue; /* do not count if not in a transaction */
+ continue; /* do not count if no XID assigned */
if (proc->waitLock != NULL)
continue; /* do not count if blocked on a lock */
count++;
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/ipc/sinvaladt.c,v 1.63 2007/01/05 22:19:38 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/ipc/sinvaladt.c,v 1.64 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "storage/ipc.h"
#include "storage/lwlock.h"
#include "storage/pmsignal.h"
+#include "storage/proc.h"
#include "storage/shmem.h"
#include "storage/sinvaladt.h"
SISeg *shmInvalBuffer;
+static LocalTransactionId nextLocalTransactionId;
+
static void CleanupInvalidationState(int status, Datum arg);
static void SISetProcStateInvalid(SISeg *segP);
size = offsetof(SISeg, procState);
size = add_size(size, mul_size(sizeof(ProcState), MaxBackends));
+ size = add_size(size, mul_size(sizeof(LocalTransactionId), MaxBackends));
+
return size;
}
SIBufferInit(void)
{
SISeg *segP;
+ Size size;
int i;
bool found;
/* Allocate space in shared memory */
+ size = offsetof(SISeg, procState);
+ size = add_size(size, mul_size(sizeof(ProcState), MaxBackends));
+
shmInvalBuffer = segP = (SISeg *)
- ShmemInitStruct("shmInvalBuffer", SInvalShmemSize(), &found);
+ ShmemInitStruct("shmInvalBuffer", size, &found);
if (found)
return;
+ segP->nextLXID = ShmemAlloc(sizeof(LocalTransactionId) * MaxBackends);
+
/* Clear message counters, save size of procState array */
segP->minMsgNum = 0;
segP->maxMsgNum = 0;
/* The buffer[] array is initially all unused, so we need not fill it */
- /* Mark all backends inactive */
+ /* Mark all backends inactive, and initialize nextLXID */
for (i = 0; i < segP->maxBackends; i++)
{
segP->procState[i].nextMsgNum = -1; /* inactive */
segP->procState[i].resetState = false;
+ segP->nextLXID[i] = InvalidLocalTransactionId;
}
}
elog(DEBUG2, "my backend id is %d", MyBackendId);
#endif /* INVALIDDEBUG */
+ /* Advertise assigned backend ID in MyProc */
+ MyProc->backendId = MyBackendId;
+
/* Reduce free slot count */
segP->freeBackends--;
+ /* Fetch next local transaction ID into local memory */
+ nextLocalTransactionId = segP->nextLXID[MyBackendId - 1];
+
/* mark myself active, with all extant messages already read */
stateP->nextMsgNum = segP->maxMsgNum;
stateP->resetState = false;
LWLockAcquire(SInvalLock, LW_EXCLUSIVE);
+ /* Update next local transaction ID for next holder of this backendID */
+ segP->nextLXID[MyBackendId - 1] = nextLocalTransactionId;
+
/* Mark myself inactive */
segP->procState[MyBackendId - 1].nextMsgNum = -1;
segP->procState[MyBackendId - 1].resetState = false;
}
}
}
+
+
+/*
+ * GetNextLocalTransactionId --- allocate a new LocalTransactionId
+ *
+ * We split VirtualTransactionIds into two parts so that it is possible
+ * to allocate a new one without any contention for shared memory, except
+ * for a bit of additional overhead during backend startup/shutdown.
+ * The high-order part of a VirtualTransactionId is a BackendId, and the
+ * low-order part is a LocalTransactionId, which we assign from a local
+ * counter. To avoid the risk of a VirtualTransactionId being reused
+ * within a short interval, successive procs occupying the same backend ID
+ * slot should use a consecutive sequence of local IDs, which is implemented
+ * by copying nextLocalTransactionId as seen above.
+ */
+LocalTransactionId
+GetNextLocalTransactionId(void)
+{
+ LocalTransactionId result;
+
+ /* loop to avoid returning InvalidLocalTransactionId at wraparound */
+ do {
+ result = nextLocalTransactionId++;
+ } while (!LocalTransactionIdIsValid(result));
+
+ return result;
+}
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/lmgr/lmgr.c,v 1.92 2007/07/25 22:16:18 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/lmgr/lmgr.c,v 1.93 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
* XactLockTableInsert
*
* Insert a lock showing that the given transaction ID is running ---
- * this is done during xact startup. The lock can then be used to wait
- * for the transaction to finish.
+ * this is done when an XID is acquired by a transaction or subtransaction.
+ * The lock can then be used to wait for the transaction to finish.
*/
void
XactLockTableInsert(TransactionId xid)
*
* Delete the lock showing that the given transaction ID is running.
* (This is never used for main transaction IDs; those locks are only
- * released implicitly at transaction end. But we do use it for subtrans
- * IDs.)
+ * released implicitly at transaction end. But we do use it for subtrans IDs.)
*/
void
XactLockTableDelete(TransactionId xid)
for (;;)
{
Assert(TransactionIdIsValid(xid));
- Assert(!TransactionIdEquals(xid, GetTopTransactionId()));
+ Assert(!TransactionIdEquals(xid, GetTopTransactionIdIfAny()));
SET_LOCKTAG_TRANSACTION(tag, xid);
for (;;)
{
Assert(TransactionIdIsValid(xid));
- Assert(!TransactionIdEquals(xid, GetTopTransactionId()));
+ Assert(!TransactionIdEquals(xid, GetTopTransactionIdIfAny()));
SET_LOCKTAG_TRANSACTION(tag, xid);
return true;
}
+
+/*
+ * VirtualXactLockTableInsert
+ *
+ * Insert a lock showing that the given virtual transaction ID is running ---
+ * this is done at main transaction start when its VXID is assigned.
+ * The lock can then be used to wait for the transaction to finish.
+ */
+void
+VirtualXactLockTableInsert(VirtualTransactionId vxid)
+{
+ LOCKTAG tag;
+
+ Assert(VirtualTransactionIdIsValid(vxid));
+
+ SET_LOCKTAG_VIRTUALTRANSACTION(tag, vxid);
+
+ (void) LockAcquire(&tag, ExclusiveLock, false, false);
+}
+
+/*
+ * VirtualXactLockTableWait
+ *
+ * Waits until the lock on the given VXID is released, which shows that
+ * the top-level transaction owning the VXID has ended.
+ */
+void
+VirtualXactLockTableWait(VirtualTransactionId vxid)
+{
+ LOCKTAG tag;
+
+ Assert(VirtualTransactionIdIsValid(vxid));
+
+ SET_LOCKTAG_VIRTUALTRANSACTION(tag, vxid);
+
+ (void) LockAcquire(&tag, ShareLock, false, false);
+
+ LockRelease(&tag, ShareLock, false);
+}
+
+/*
+ * ConditionalVirtualXactLockTableWait
+ *
+ * As above, but only lock if we can get the lock without blocking.
+ * Returns TRUE if the lock was acquired.
+ */
+bool
+ConditionalVirtualXactLockTableWait(VirtualTransactionId vxid)
+{
+ LOCKTAG tag;
+
+ Assert(VirtualTransactionIdIsValid(vxid));
+
+ SET_LOCKTAG_VIRTUALTRANSACTION(tag, vxid);
+
+ if (LockAcquire(&tag, ShareLock, false, true) == LOCKACQUIRE_NOT_AVAIL)
+ return false;
+
+ LockRelease(&tag, ShareLock, false);
+
+ return true;
+}
+
+
/*
* LockDatabaseObject
*
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/lmgr/lock.c,v 1.177 2007/07/16 21:09:50 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/lmgr/lock.c,v 1.178 2007/09/05 18:10:47 tgl Exp $
*
* NOTES
* A lock table is a shared memory hash table. When
/*
* GetLockConflicts
- * Get a list of TransactionIds of xacts currently holding locks
+ * Get an array of VirtualTransactionIds of xacts currently holding locks
* that would conflict with the specified lock/lockmode.
* xacts merely awaiting such a lock are NOT reported.
*
+ * The result array is palloc'd and is terminated with an invalid VXID.
+ *
* Of course, the result could be out of date by the time it's returned,
* so use of this function has to be thought about carefully.
*
- * Only top-level XIDs are reported. Note we never include the current xact
- * in the result list, since an xact never blocks itself.
+ * Note we never include the current xact's vxid in the result array,
+ * since an xact never blocks itself. Also, prepared transactions are
+ * ignored, which is a bit more debatable but is appropriate for current
+ * uses of the result.
*/
-List *
+VirtualTransactionId *
GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode)
{
- List *result = NIL;
+ VirtualTransactionId *vxids;
LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
LockMethod lockMethodTable;
LOCK *lock;
PROCLOCK *proclock;
uint32 hashcode;
LWLockId partitionLock;
+ int count = 0;
if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
elog(ERROR, "unrecognized lock method: %d", lockmethodid);
if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
elog(ERROR, "unrecognized lock mode: %d", lockmode);
+ /*
+ * Allocate memory to store results, and fill with InvalidVXID. We
+ * only need enough space for MaxBackends + a terminator, since
+ * prepared xacts don't count.
+ */
+ vxids = (VirtualTransactionId *)
+ palloc0(sizeof(VirtualTransactionId) * (MaxBackends + 1));
+
/*
* Look up the lock object matching the tag.
*/
* on this lockable object.
*/
LWLockRelease(partitionLock);
- return NIL;
+ return vxids;
}
/*
/* A backend never blocks itself */
if (proc != MyProc)
{
- /* Fetch xid just once - see GetNewTransactionId */
- TransactionId xid = proc->xid;
+ VirtualTransactionId vxid;
+
+ GET_VXID_FROM_PGPROC(vxid, *proc);
/*
- * Race condition: during xact commit/abort we zero out
- * PGPROC's xid before we mark its locks released. If we see
- * zero in the xid field, assume the xact is in process of
- * shutting down and act as though the lock is already
- * released.
+ * If we see an invalid VXID, then either the xact has already
+ * committed (or aborted), or it's a prepared xact. In
+ * either case we may ignore it.
*/
- if (TransactionIdIsValid(xid))
- result = lappend_xid(result, xid);
+ if (VirtualTransactionIdIsValid(vxid))
+ vxids[count++] = vxid;
}
}
LWLockRelease(partitionLock);
- return result;
+ if (count > MaxBackends) /* should never happen */
+ elog(PANIC, "too many conflicting locks found");
+
+ return vxids;
}
* Do the preparatory work for a PREPARE: make 2PC state file records
* for all locks currently held.
*
- * Non-transactional locks are ignored.
+ * Non-transactional locks are ignored, as are VXID locks.
*
* There are some special cases that we error out on: we can't be holding
* any session locks (should be OK since only VACUUM uses those) and we
if (!LockMethods[LOCALLOCK_LOCKMETHOD(*locallock)]->transactional)
continue;
+ /*
+ * Ignore VXID locks. We don't want those to be held by prepared
+ * transactions, since they aren't meaningful after a restart.
+ */
+ if (locallock->tag.lock.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
+ continue;
+
/* Ignore it if we don't actually hold the lock */
if (locallock->nLocks <= 0)
continue;
if (!LockMethods[LOCALLOCK_LOCKMETHOD(*locallock)]->transactional)
continue;
+ /* Ignore VXID locks */
+ if (locallock->tag.lock.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
+ continue;
+
/* We already checked there are no session locks */
/* Mark the proclock to show we need to release this lockmode */
if (!LockMethods[LOCK_LOCKMETHOD(*lock)]->transactional)
goto next_item;
+ /* Ignore VXID locks */
+ if (lock->tag.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
+ goto next_item;
+
PROCLOCK_PRINT("PostPrepare_Locks", proclock);
LOCK_PRINT("PostPrepare_Locks", lock, 0);
Assert(lock->nRequested >= 0);
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/lmgr/proc.c,v 1.192 2007/08/28 03:23:44 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/lmgr/proc.c,v 1.193 2007/09/05 18:10:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
*/
SHMQueueElemInit(&(MyProc->links));
MyProc->waitStatus = STATUS_OK;
+ MyProc->lxid = InvalidLocalTransactionId;
MyProc->xid = InvalidTransactionId;
MyProc->xmin = InvalidTransactionId;
MyProc->pid = MyProcPid;
- /* databaseId and roleId will be filled in later */
+ /* backendId, databaseId and roleId will be filled in later */
+ MyProc->backendId = InvalidBackendId;
MyProc->databaseId = InvalidOid;
MyProc->roleId = InvalidOid;
MyProc->inCommit = false;
*
* Auxiliary processes are presently not expected to wait for real (lockmgr)
* locks, so we need not set up the deadlock checker. They are never added
- * to the ProcArray or the sinval messaging mechanism, either.
+ * to the ProcArray or the sinval messaging mechanism, either. They also
+ * don't get a VXID assigned, since this is only useful when we actually
+ * hold lockmgr locks.
*/
void
InitAuxiliaryProcess(void)
*/
SHMQueueElemInit(&(MyProc->links));
MyProc->waitStatus = STATUS_OK;
+ MyProc->lxid = InvalidLocalTransactionId;
MyProc->xid = InvalidTransactionId;
MyProc->xmin = InvalidTransactionId;
+ MyProc->backendId = InvalidBackendId;
MyProc->databaseId = InvalidOid;
MyProc->roleId = InvalidOid;
MyProc->inCommit = false;
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/smgr/smgr.c,v 1.105 2007/07/20 16:29:53 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/smgr/smgr.c,v 1.106 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
return;
/*
- * Make a non-transactional XLOG entry showing the file creation. It's
- * non-transactional because we should replay it whether the transaction
- * commits or not; if not, the file will be dropped at abort time.
+ * Make an XLOG entry showing the file creation. If we abort, the file
+ * will be dropped at abort time.
*/
xlrec.rnode = reln->smgr_rnode;
rdata.buffer = InvalidBuffer;
rdata.next = NULL;
- lsn = XLogInsert(RM_SMGR_ID, XLOG_SMGR_CREATE | XLOG_NO_TRAN, &rdata);
+ lsn = XLogInsert(RM_SMGR_ID, XLOG_SMGR_CREATE, &rdata);
/* Add the relation to the list of stuff to delete at abort */
pending = (PendingRelDelete *)
if (!isTemp)
{
/*
- * Make a non-transactional XLOG entry showing the file truncation.
- * It's non-transactional because we should replay it whether the
- * transaction commits or not; the underlying file change is certainly
- * not reversible.
+ * Make an XLOG entry showing the file truncation.
*/
XLogRecPtr lsn;
XLogRecData rdata;
rdata.buffer = InvalidBuffer;
rdata.next = NULL;
- lsn = XLogInsert(RM_SMGR_ID, XLOG_SMGR_TRUNCATE | XLOG_NO_TRAN,
- &rdata);
+ lsn = XLogInsert(RM_SMGR_ID, XLOG_SMGR_TRUNCATE, &rdata);
}
}
* *ptr is set to point to a freshly-palloc'd array of RelFileNodes.
* If there are no relations to be deleted, *ptr is set to NULL.
*
+ * If haveNonTemp isn't NULL, the bool it points to gets set to true if
+ * there is any non-temp table pending to be deleted; false if not.
+ *
* Note that the list does not include anything scheduled for termination
* by upper-level transactions.
*/
int
-smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr)
+smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr, bool *haveNonTemp)
{
int nestLevel = GetCurrentTransactionNestLevel();
int nrels;
PendingRelDelete *pending;
nrels = 0;
+ if (haveNonTemp)
+ *haveNonTemp = false;
for (pending = pendingDeletes; pending != NULL; pending = pending->next)
{
if (pending->nestLevel >= nestLevel && pending->atCommit == forCommit)
{
if (pending->nestLevel >= nestLevel && pending->atCommit == forCommit)
*rptr++ = pending->relnode;
+ if (haveNonTemp && !pending->isTemp)
+ *haveNonTemp = true;
}
return nrels;
}
* Copyright (c) 2002-2007, PostgreSQL Global Development Group
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/lockfuncs.c,v 1.28 2007/01/05 22:19:41 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/lockfuncs.c,v 1.29 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
"page",
"tuple",
"transactionid",
+ "virtualxid",
"object",
"userlock",
"advisory"
int currIdx; /* current PROCLOCK index */
} PG_Lock_Status;
+
+/*
+ * VXIDGetDatum - Construct a text representation of a VXID
+ *
+ * This is currently only used in pg_lock_status, so we put it here.
+ */
+static Datum
+VXIDGetDatum(BackendId bid, LocalTransactionId lxid)
+{
+ /*
+ * The representation is "<bid>/<lxid>", decimal and unsigned decimal
+ * respectively. Note that elog.c also knows how to format a vxid.
+ */
+ char vxidstr[32];
+
+ snprintf(vxidstr, sizeof(vxidstr), "%d/%u", bid, lxid);
+
+ return DirectFunctionCall1(textin, CStringGetDatum(vxidstr));
+}
+
+
/*
* pg_lock_status - produce a view with one row per held or awaited lock mode
*/
/* build tupdesc for result tuples */
/* this had better match pg_locks view in system_views.sql */
- tupdesc = CreateTemplateTupleDesc(13, false);
+ tupdesc = CreateTemplateTupleDesc(14, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "locktype",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "database",
INT4OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 5, "tuple",
INT2OID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 6, "transactionid",
+ TupleDescInitEntry(tupdesc, (AttrNumber) 6, "virtualxid",
+ TEXTOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 7, "transactionid",
XIDOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 7, "classid",
+ TupleDescInitEntry(tupdesc, (AttrNumber) 8, "classid",
OIDOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 8, "objid",
+ TupleDescInitEntry(tupdesc, (AttrNumber) 9, "objid",
OIDOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 9, "objsubid",
+ TupleDescInitEntry(tupdesc, (AttrNumber) 10, "objsubid",
INT2OID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 10, "transaction",
- XIDOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 11, "pid",
+ TupleDescInitEntry(tupdesc, (AttrNumber) 11, "virtualtransaction",
+ TEXTOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 12, "pid",
INT4OID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 12, "mode",
+ TupleDescInitEntry(tupdesc, (AttrNumber) 13, "mode",
TEXTOID, -1, 0);
- TupleDescInitEntry(tupdesc, (AttrNumber) 13, "granted",
+ TupleDescInitEntry(tupdesc, (AttrNumber) 14, "granted",
BOOLOID, -1, 0);
funcctx->tuple_desc = BlessTupleDesc(tupdesc);
LOCKMODE mode = 0;
const char *locktypename;
char tnbuf[32];
- Datum values[13];
- char nulls[13];
+ Datum values[14];
+ char nulls[14];
HeapTuple tuple;
Datum result;
values[0] = DirectFunctionCall1(textin,
CStringGetDatum(locktypename));
-
switch (lock->tag.locktag_type)
{
case LOCKTAG_RELATION:
nulls[6] = 'n';
nulls[7] = 'n';
nulls[8] = 'n';
+ nulls[9] = 'n';
break;
case LOCKTAG_PAGE:
values[1] = ObjectIdGetDatum(lock->tag.locktag_field1);
nulls[6] = 'n';
nulls[7] = 'n';
nulls[8] = 'n';
+ nulls[9] = 'n';
break;
case LOCKTAG_TUPLE:
values[1] = ObjectIdGetDatum(lock->tag.locktag_field1);
nulls[6] = 'n';
nulls[7] = 'n';
nulls[8] = 'n';
+ nulls[9] = 'n';
break;
case LOCKTAG_TRANSACTION:
- values[5] = TransactionIdGetDatum(lock->tag.locktag_field1);
+ values[6] = TransactionIdGetDatum(lock->tag.locktag_field1);
+ nulls[1] = 'n';
+ nulls[2] = 'n';
+ nulls[3] = 'n';
+ nulls[4] = 'n';
+ nulls[5] = 'n';
+ nulls[7] = 'n';
+ nulls[8] = 'n';
+ nulls[9] = 'n';
+ break;
+ case LOCKTAG_VIRTUALTRANSACTION:
+ values[5] = VXIDGetDatum(lock->tag.locktag_field1,
+ lock->tag.locktag_field2);
nulls[1] = 'n';
nulls[2] = 'n';
nulls[3] = 'n';
nulls[6] = 'n';
nulls[7] = 'n';
nulls[8] = 'n';
+ nulls[9] = 'n';
break;
case LOCKTAG_OBJECT:
case LOCKTAG_USERLOCK:
case LOCKTAG_ADVISORY:
default: /* treat unknown locktags like OBJECT */
values[1] = ObjectIdGetDatum(lock->tag.locktag_field1);
- values[6] = ObjectIdGetDatum(lock->tag.locktag_field2);
- values[7] = ObjectIdGetDatum(lock->tag.locktag_field3);
- values[8] = Int16GetDatum(lock->tag.locktag_field4);
+ values[7] = ObjectIdGetDatum(lock->tag.locktag_field2);
+ values[8] = ObjectIdGetDatum(lock->tag.locktag_field3);
+ values[9] = Int16GetDatum(lock->tag.locktag_field4);
nulls[2] = 'n';
nulls[3] = 'n';
nulls[4] = 'n';
nulls[5] = 'n';
+ nulls[6] = 'n';
break;
}
- values[9] = TransactionIdGetDatum(proc->xid);
+ values[10] = VXIDGetDatum(proc->backendId, proc->lxid);
if (proc->pid != 0)
- values[10] = Int32GetDatum(proc->pid);
+ values[11] = Int32GetDatum(proc->pid);
else
- nulls[10] = 'n';
- values[11] = DirectFunctionCall1(textin,
+ nulls[11] = 'n';
+ values[12] = DirectFunctionCall1(textin,
CStringGetDatum(GetLockmodeName(LOCK_LOCKMETHOD(*lock),
mode)));
- values[12] = BoolGetDatum(granted);
+ values[13] = BoolGetDatum(granted);
tuple = heap_formtuple(funcctx->tuple_desc, values, nulls);
result = HeapTupleGetDatum(tuple);
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.195 2007/08/23 01:24:43 adunstan Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.196 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postmaster/postmaster.h"
#include "postmaster/syslogger.h"
#include "storage/ipc.h"
+#include "storage/proc.h"
#include "tcop/tcopprot.h"
#include "utils/memutils.h"
#include "utils/ps_status.h"
if (MyProcPort == NULL)
i = format_len;
break;
+ case 'v':
+ /* keep VXID format in sync with lockfuncs.c */
+ if (MyProc != NULL)
+ appendStringInfo(buf, "%d/%u",
+ MyProc->backendId, MyProc->lxid);
+ break;
case 'x':
- if (MyProcPort)
- appendStringInfo(buf, "%u", GetTopTransactionId());
+ appendStringInfo(buf, "%u", GetTopTransactionIdIfAny());
break;
case '%':
appendStringInfoChar(buf, '%');
appendStringInfoString(&buf, formatted_start_time);
appendStringInfoChar(&buf, ',');
-
/* Transaction id */
- if (MyProcPort)
- {
- if (IsTransactionState())
- appendStringInfo(&buf, "%u", GetTopTransactionId());
- else
- appendStringInfo(&buf, "%u", InvalidTransactionId);
- }
+ appendStringInfo(&buf, "%u", GetTopTransactionIdIfAny());
appendStringInfoChar(&buf, ',');
# %c = session id
# %l = session line number
# %s = session start timestamp
- # %x = transaction id
+ # %v = virtual transaction id
+ # %x = transaction id (0 if none)
# %q = stop here in non-session
# processes
# %% = '%'
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/access/xact.h,v 1.88 2007/08/01 22:45:09 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/xact.h,v 1.89 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
extern bool IsTransactionState(void);
extern bool IsAbortedTransactionBlockState(void);
extern TransactionId GetTopTransactionId(void);
+extern TransactionId GetTopTransactionIdIfAny(void);
extern TransactionId GetCurrentTransactionId(void);
extern TransactionId GetCurrentTransactionIdIfAny(void);
extern SubTransactionId GetCurrentSubTransactionId(void);
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.82 2007/08/01 22:45:09 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.83 2007/09/05 18:10:48 tgl Exp $
*/
#ifndef XLOG_H
#define XLOG_H
*/
#define XLR_BKP_REMOVABLE 0x01
-/*
- * Sometimes we log records which are out of transaction control.
- * Rmgr may "or" XLOG_NO_TRAN into info passed to XLogInsert to indicate this.
- */
-#define XLOG_NO_TRAN XLR_INFO_MASK
-
/* Sync methods */
#define SYNC_METHOD_FSYNC 0
#define SYNC_METHOD_FDATASYNC 1
extern TimeLineID ThisTimeLineID; /* current TLI */
extern bool InRecovery;
-extern XLogRecPtr MyLastRecPtr;
-extern bool MyXactMadeXLogEntry;
-extern bool MyXactMadeTempRelUpdate;
-extern XLogRecPtr ProcLastRecEnd;
+extern XLogRecPtr XactLastRecEnd;
/* these variables are GUC parameters related to XLOG */
extern int CheckPointSegments;
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/c.h,v 1.220 2007/07/25 12:22:52 mha Exp $
+ * $PostgreSQL: pgsql/src/include/c.h,v 1.221 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
typedef uint32 TransactionId;
+typedef uint32 LocalTransactionId;
+
typedef uint32 SubTransactionId;
#define InvalidSubTransactionId ((SubTransactionId) 0)
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.422 2007/09/04 16:41:42 adunstan Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.423 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
*/
/* yyyymmddN */
-#define CATALOG_VERSION_NO 200709041
+#define CATALOG_VERSION_NO 200709042
#endif
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/storage/lmgr.h,v 1.58 2007/06/19 20:13:22 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/lmgr.h,v 1.59 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
extern void XactLockTableWait(TransactionId xid);
extern bool ConditionalXactLockTableWait(TransactionId xid);
+/* Lock a VXID (used to wait for a transaction to finish) */
+extern void VirtualXactLockTableInsert(VirtualTransactionId vxid);
+extern void VirtualXactLockTableWait(VirtualTransactionId vxid);
+extern bool ConditionalVirtualXactLockTableWait(VirtualTransactionId vxid);
+
/* Lock a general object (other than a relation) of the current database */
extern void LockDatabaseObject(Oid classid, Oid objid, uint16 objsubid,
LOCKMODE lockmode);
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.106 2007/06/19 20:13:22 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.107 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#define LOCK_H_
#include "nodes/pg_list.h"
+#include "storage/backendid.h"
#include "storage/itemptr.h"
#include "storage/lwlock.h"
#include "storage/shmem.h"
#endif /* LOCK_DEBUG */
+/*
+ * Top-level transactions are identified by VirtualTransactionIDs comprising
+ * the BackendId of the backend running the xact, plus a locally-assigned
+ * LocalTransactionId. These are guaranteed unique over the short term,
+ * but will be reused after a database restart; hence they should never
+ * be stored on disk.
+ *
+ * Note that struct VirtualTransactionId can not be assumed to be atomically
+ * assignable as a whole. However, type LocalTransactionId is assumed to
+ * be atomically assignable, and the backend ID doesn't change often enough
+ * to be a problem, so we can fetch or assign the two fields separately.
+ * We deliberately refrain from using the struct within PGPROC, to prevent
+ * coding errors from trying to use struct assignment with it; instead use
+ * GET_VXID_FROM_PGPROC().
+ */
+typedef struct
+{
+ BackendId backendId; /* determined at backend startup */
+ LocalTransactionId localTransactionId; /* backend-local transaction id */
+} VirtualTransactionId;
+
+#define InvalidLocalTransactionId 0
+#define LocalTransactionIdIsValid(lxid) ((lxid) != InvalidLocalTransactionId)
+#define VirtualTransactionIdIsValid(vxid) \
+ (((vxid).backendId != InvalidBackendId) && \
+ LocalTransactionIdIsValid((vxid).localTransactionId))
+#define GET_VXID_FROM_PGPROC(vxid, proc) \
+ ((vxid).backendId = (proc).backendId, \
+ (vxid).localTransactionId = (proc).lxid)
+
+
/*
* LOCKMODE is an integer (1..N) indicating a lock type. LOCKMASK is a bit
* mask indicating a set of held or requested lock types (the bit 1<<mode
/* ID info for a tuple is PAGE info + OffsetNumber */
LOCKTAG_TRANSACTION, /* transaction (for waiting for xact done) */
/* ID info for a transaction is its TransactionId */
+ LOCKTAG_VIRTUALTRANSACTION, /* virtual transaction (ditto) */
+ /* ID info for a virtual transaction is its VirtualTransactionId */
LOCKTAG_OBJECT, /* non-relation database object */
/* ID info for an object is DB OID + CLASS OID + OBJECT OID + SUBID */
(locktag).locktag_type = LOCKTAG_TRANSACTION, \
(locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
+#define SET_LOCKTAG_VIRTUALTRANSACTION(locktag,vxid) \
+ ((locktag).locktag_field1 = (vxid).backendId, \
+ (locktag).locktag_field2 = (vxid).localTransactionId, \
+ (locktag).locktag_field3 = 0, \
+ (locktag).locktag_field4 = 0, \
+ (locktag).locktag_type = LOCKTAG_VIRTUALTRANSACTION, \
+ (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
+
#define SET_LOCKTAG_OBJECT(locktag,dboid,classoid,objoid,objsubid) \
((locktag).locktag_field1 = (dboid), \
(locktag).locktag_field2 = (classoid), \
extern void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks);
extern void LockReleaseCurrentOwner(void);
extern void LockReassignCurrentOwner(void);
-extern List *GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode);
+extern VirtualTransactionId *GetLockConflicts(const LOCKTAG *locktag,
+ LOCKMODE lockmode);
extern void AtPrepare_Locks(void);
extern void PostPrepare_Locks(TransactionId xid);
extern int LockCheckConflicts(LockMethod lockMethodTable,
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/storage/proc.h,v 1.99 2007/07/25 12:22:53 mha Exp $
+ * $PostgreSQL: pgsql/src/include/storage/proc.h,v 1.100 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
PGSemaphoreData sem; /* ONE semaphore to sleep on */
int waitStatus; /* STATUS_WAITING, STATUS_OK or STATUS_ERROR */
- TransactionId xid; /* transaction currently being executed by
- * this proc */
+ LocalTransactionId lxid; /* local id of top-level transaction currently
+ * being executed by this proc, if running;
+ * else InvalidLocalTransactionId */
+
+ TransactionId xid; /* id of top-level transaction currently being
+ * executed by this proc, if running and XID
+ * is assigned; else InvalidTransactionId */
TransactionId xmin; /* minimal running XID as it was when we were
* starting our xact, excluding LAZY VACUUM:
* xid >= xmin ! */
int pid; /* This backend's process id, or 0 */
+ BackendId backendId; /* This backend's backend ID (if assigned) */
Oid databaseId; /* OID of database this backend is using */
Oid roleId; /* OID of role using this backend */
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/storage/procarray.h,v 1.14 2007/06/01 19:38:07 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/procarray.h,v 1.15 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
extern int BackendXidGetPid(TransactionId xid);
extern bool IsBackendPid(int pid);
+extern VirtualTransactionId *GetCurrentVirtualXIDs(TransactionId limitXmin);
extern int CountActiveBackends(void);
extern int CountDBBackends(Oid databaseid);
extern int CountUserBackends(Oid roleid);
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/storage/sinvaladt.h,v 1.42 2007/01/05 22:19:58 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/storage/sinvaladt.h,v 1.43 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
int maxBackends; /* size of procState array */
int freeBackends; /* number of empty procState slots */
+ /*
+ * Next LocalTransactionId to use for each idle backend slot. We keep
+ * this here because it is indexed by BackendId and it is convenient to
+ * copy the value to and from local memory when MyBackendId is set.
+ */
+ LocalTransactionId *nextLXID; /* array of maxBackends entries */
+
/*
* Circular buffer holding shared-inval messages
*/
SharedInvalidationMessage *data);
extern void SIDelExpiredDataEntries(SISeg *segP);
+extern LocalTransactionId GetNextLocalTransactionId(void);
+
#endif /* SINVALADT_H */
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/storage/smgr.h,v 1.58 2007/01/17 16:25:01 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/smgr.h,v 1.59 2007/09/05 18:10:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
bool isTemp);
extern void smgrimmedsync(SMgrRelation reln);
extern void smgrDoPendingDeletes(bool isCommit);
-extern int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr);
+extern int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr,
+ bool *haveNonTemp);
extern void AtSubCommit_smgr(void);
extern void AtSubAbort_smgr(void);
extern void PostPrepare_smgr(void);
pg_cursors | SELECT c.name, c.statement, c.is_holdable, c.is_binary, c.is_scrollable, c.creation_time FROM pg_cursor() c(name text, statement text, is_holdable boolean, is_binary boolean, is_scrollable boolean, creation_time timestamp with time zone);
pg_group | SELECT pg_authid.rolname AS groname, pg_authid.oid AS grosysid, ARRAY(SELECT pg_auth_members.member FROM pg_auth_members WHERE (pg_auth_members.roleid = pg_authid.oid)) AS grolist FROM pg_authid WHERE (NOT pg_authid.rolcanlogin);
pg_indexes | SELECT n.nspname AS schemaname, c.relname AS tablename, i.relname AS indexname, t.spcname AS tablespace, pg_get_indexdef(i.oid) AS indexdef FROM ((((pg_index x JOIN pg_class c ON ((c.oid = x.indrelid))) JOIN pg_class i ON ((i.oid = x.indexrelid))) LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) LEFT JOIN pg_tablespace t ON ((t.oid = i.reltablespace))) WHERE ((c.relkind = 'r'::"char") AND (i.relkind = 'i'::"char"));
- pg_locks | SELECT l.locktype, l.database, l.relation, l.page, l.tuple, l.transactionid, l.classid, l.objid, l.objsubid, l.transaction, l.pid, l.mode, l.granted FROM pg_lock_status() l(locktype text, database oid, relation oid, page integer, tuple smallint, transactionid xid, classid oid, objid oid, objsubid smallint, transaction xid, pid integer, mode text, granted boolean);
+ pg_locks | SELECT l.locktype, l.database, l.relation, l.page, l.tuple, l.virtualxid, l.transactionid, l.classid, l.objid, l.objsubid, l.virtualtransaction, l.pid, l.mode, l.granted FROM pg_lock_status() l(locktype text, database oid, relation oid, page integer, tuple smallint, virtualxid text, transactionid xid, classid oid, objid oid, objsubid smallint, virtualtransaction text, pid integer, mode text, granted boolean);
pg_prepared_statements | SELECT p.name, p.statement, p.prepare_time, p.parameter_types, p.from_sql FROM pg_prepared_statement() p(name text, statement text, prepare_time timestamp with time zone, parameter_types regtype[], from_sql boolean);
pg_prepared_xacts | SELECT p.transaction, p.gid, p.prepared, u.rolname AS owner, d.datname AS database FROM ((pg_prepared_xact() p(transaction xid, gid text, prepared timestamp with time zone, ownerid oid, dbid oid) LEFT JOIN pg_authid u ON ((p.ownerid = u.oid))) LEFT JOIN pg_database d ON ((p.dbid = d.oid)));
pg_roles | SELECT pg_authid.rolname, pg_authid.rolsuper, pg_authid.rolinherit, pg_authid.rolcreaterole, pg_authid.rolcreatedb, pg_authid.rolcatupdate, pg_authid.rolcanlogin, pg_authid.rolconnlimit, '********'::text AS rolpassword, pg_authid.rolvaliduntil, pg_authid.rolconfig, pg_authid.oid FROM pg_authid;
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