* looked up again. Now we use specialized access code so that the commit
* log can be broken into relatively small, independent segments.
*
+ * XLOG interactions: this module generates an XLOG record whenever a new
+ * CLOG page is initialized to zeroes. Other writes of CLOG come from
+ * recording of transaction commit or abort in xact.c, which generates its
+ * own XLOG records for these events and will re-perform the status update
+ * on redo; so we need make no additional XLOG entry here. Also, the XLOG
+ * is guaranteed flushed through the XLOG commit record before we are called
+ * to log a commit, so the WAL rule "write xlog before data" is satisfied
+ * automatically for commits, and we don't really care for aborts. Therefore,
+ * we don't need to mark CLOG pages with LSN information; we have enough
+ * synchronization already.
+ *
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/access/transam/clog.c,v 1.22 2004/07/03 02:55:56 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/clog.c,v 1.23 2004/08/23 23:22:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
-#include <fcntl.h>
-#include <dirent.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
#include "access/clog.h"
#include "access/slru.h"
-#include "miscadmin.h"
-#include "storage/lwlock.h"
+#include "postmaster/bgwriter.h"
/*
- * Defines for CLOG page and segment sizes. A page is the same BLCKSZ
- * as is used everywhere else in Postgres.
+ * Defines for CLOG page sizes. A page is the same BLCKSZ as is used
+ * everywhere else in Postgres.
*
* Note: because TransactionIds are 32 bits and wrap around at 0xFFFFFFFF,
* CLOG page numbering also wraps around at 0xFFFFFFFF/CLOG_XACTS_PER_PAGE,
#define TransactionIdToBIndex(xid) ((xid) % (TransactionId) CLOG_XACTS_PER_BYTE)
-/*----------
- * Shared-memory data structures for CLOG control
- *
- * XLOG interactions: this module generates an XLOG record whenever a new
- * CLOG page is initialized to zeroes. Other writes of CLOG come from
- * recording of transaction commit or abort in xact.c, which generates its
- * own XLOG records for these events and will re-perform the status update
- * on redo; so we need make no additional XLOG entry here. Also, the XLOG
- * is guaranteed flushed through the XLOG commit record before we are called
- * to log a commit, so the WAL rule "write xlog before data" is satisfied
- * automatically for commits, and we don't really care for aborts. Therefore,
- * we don't need to mark CLOG pages with LSN information; we have enough
- * synchronization already.
- *----------
+/*
+ * Link to shared-memory data structures for CLOG control
*/
-
-
static SlruCtlData ClogCtlData;
-static SlruCtl ClogCtl = &ClogCtlData;
+#define ClogCtl (&ClogCtlData)
static int ZeroCLOGPage(int pageno, bool writeXlog);
int pageno = TransactionIdToPage(xid);
int byteno = TransactionIdToByte(xid);
int bshift = TransactionIdToBIndex(xid) * CLOG_BITS_PER_XACT;
+ int slotno;
char *byteptr;
char byteval;
status == TRANSACTION_STATUS_ABORTED ||
status == TRANSACTION_STATUS_SUB_COMMITTED);
- LWLockAcquire(ClogCtl->ControlLock, LW_EXCLUSIVE);
+ LWLockAcquire(CLogControlLock, LW_EXCLUSIVE);
- byteptr = SimpleLruReadPage(ClogCtl, pageno, xid, true);
- byteptr += byteno;
+ slotno = SimpleLruReadPage(ClogCtl, pageno, xid);
+ byteptr = ClogCtl->shared->page_buffer[slotno] + byteno;
/* Current state should be 0, subcommitted or target state */
Assert(((*byteptr >> bshift) & CLOG_XACT_BITMASK) == 0 ||
byteval |= (status << bshift);
*byteptr = byteval;
- /* ...->page_status[slotno] = SLRU_PAGE_DIRTY; already done */
+ ClogCtl->shared->page_status[slotno] = SLRU_PAGE_DIRTY;
- LWLockRelease(ClogCtl->ControlLock);
+ LWLockRelease(CLogControlLock);
}
/*
int pageno = TransactionIdToPage(xid);
int byteno = TransactionIdToByte(xid);
int bshift = TransactionIdToBIndex(xid) * CLOG_BITS_PER_XACT;
+ int slotno;
char *byteptr;
XidStatus status;
- LWLockAcquire(ClogCtl->ControlLock, LW_EXCLUSIVE);
+ LWLockAcquire(CLogControlLock, LW_EXCLUSIVE);
- byteptr = SimpleLruReadPage(ClogCtl, pageno, xid, false);
- byteptr += byteno;
+ slotno = SimpleLruReadPage(ClogCtl, pageno, xid);
+ byteptr = ClogCtl->shared->page_buffer[slotno] + byteno;
status = (*byteptr >> bshift) & CLOG_XACT_BITMASK;
- LWLockRelease(ClogCtl->ControlLock);
+ LWLockRelease(CLogControlLock);
return status;
}
void
CLOGShmemInit(void)
{
- SimpleLruInit(ClogCtl, "CLOG Ctl", "pg_clog");
ClogCtl->PagePrecedes = CLOGPagePrecedes;
+ SimpleLruInit(ClogCtl, "CLOG Ctl", CLogControlLock, "pg_clog");
}
/*
{
int slotno;
- LWLockAcquire(ClogCtl->ControlLock, LW_EXCLUSIVE);
+ LWLockAcquire(CLogControlLock, LW_EXCLUSIVE);
/* Create and zero the first page of the commit log */
slotno = ZeroCLOGPage(0, false);
/* Make sure it's written out */
SimpleLruWritePage(ClogCtl, slotno, NULL);
- /* Assert(ClogCtl->page_status[slotno] == SLRU_PAGE_CLEAN); */
+ Assert(ClogCtl->shared->page_status[slotno] == SLRU_PAGE_CLEAN);
- LWLockRelease(ClogCtl->ControlLock);
+ LWLockRelease(CLogControlLock);
}
/*
static int
ZeroCLOGPage(int pageno, bool writeXlog)
{
- int slotno = SimpleLruZeroPage(ClogCtl, pageno);
+ int slotno;
+
+ slotno = SimpleLruZeroPage(ClogCtl, pageno);
if (writeXlog)
WriteZeroPageXlogRec(pageno);
/*
* Initialize our idea of the latest page number.
*/
- SimpleLruSetLatestPage(ClogCtl,
- TransactionIdToPage(ShmemVariableCache->nextXid));
+ ClogCtl->shared->latest_page_number = TransactionIdToPage(ShmemVariableCache->nextXid);
}
/*
void
ShutdownCLOG(void)
{
+ /* Flush dirty CLOG pages to disk */
SimpleLruFlush(ClogCtl, false);
}
void
CheckPointCLOG(void)
{
+ /* Flush dirty CLOG pages to disk */
SimpleLruFlush(ClogCtl, true);
}
pageno = TransactionIdToPage(newestXact);
- LWLockAcquire(ClogCtl->ControlLock, LW_EXCLUSIVE);
+ LWLockAcquire(CLogControlLock, LW_EXCLUSIVE);
/* Zero the page and make an XLOG entry about it */
ZeroCLOGPage(pageno, true);
- LWLockRelease(ClogCtl->ControlLock);
+ LWLockRelease(CLogControlLock);
}
* We pass the *page* containing oldestXact to SimpleLruTruncate.
*/
cutoffPage = TransactionIdToPage(oldestXact);
+
+ /* Check to see if there's any files that could be removed */
+ if (!SlruScanDirectory(ClogCtl, cutoffPage, false))
+ return; /* nothing to remove */
+
+ /* Perform a CHECKPOINT */
+ RequestCheckpoint(true);
+
+ /* Now we can remove the old CLOG segment(s) */
SimpleLruTruncate(ClogCtl, cutoffPage);
}
rdata.data = (char *) (&pageno);
rdata.len = sizeof(int);
rdata.next = NULL;
- (void) XLogInsert(RM_SLRU_ID, CLOG_ZEROPAGE | XLOG_NO_TRAN, &rdata);
+ (void) XLogInsert(RM_CLOG_ID, CLOG_ZEROPAGE | XLOG_NO_TRAN, &rdata);
}
-/* Redo a ZEROPAGE action during WAL replay */
+/*
+ * CLOG resource manager's routines
+ */
void
-clog_zeropage_redo(int pageno)
+clog_redo(XLogRecPtr lsn, XLogRecord *record)
{
- int slotno;
+ uint8 info = record->xl_info & ~XLR_INFO_MASK;
- LWLockAcquire(ClogCtl->ControlLock, LW_EXCLUSIVE);
+ if (info == CLOG_ZEROPAGE)
+ {
+ int pageno;
+ int slotno;
- slotno = ZeroCLOGPage(pageno, false);
- SimpleLruWritePage(ClogCtl, slotno, NULL);
- /* Assert(ClogCtl->page_status[slotno] == SLRU_PAGE_CLEAN); */
+ memcpy(&pageno, XLogRecGetData(record), sizeof(int));
+
+ LWLockAcquire(CLogControlLock, LW_EXCLUSIVE);
+
+ slotno = ZeroCLOGPage(pageno, false);
+ SimpleLruWritePage(ClogCtl, slotno, NULL);
+ Assert(ClogCtl->shared->page_status[slotno] == SLRU_PAGE_CLEAN);
+
+ LWLockRelease(CLogControlLock);
+ }
+}
+
+void
+clog_undo(XLogRecPtr lsn, XLogRecord *record)
+{
+}
+
+void
+clog_desc(char *buf, uint8 xl_info, char *rec)
+{
+ uint8 info = xl_info & ~XLR_INFO_MASK;
+
+ if (info == CLOG_ZEROPAGE)
+ {
+ int pageno;
- LWLockRelease(ClogCtl->ControlLock);
+ memcpy(&pageno, rec, sizeof(int));
+ sprintf(buf + strlen(buf), "zeropage: %d", pageno);
+ }
+ else
+ strcat(buf, "UNKNOWN");
}
*
* Resource managers definition
*
- * $PostgreSQL: pgsql/src/backend/access/transam/rmgr.c,v 1.14 2004/07/21 22:31:20 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/rmgr.c,v 1.15 2004/08/23 23:22:44 tgl Exp $
*/
#include "postgres.h"
#include "access/heapam.h"
#include "access/nbtree.h"
#include "access/rtree.h"
-#include "access/slru.h"
+#include "access/clog.h"
#include "access/xact.h"
#include "access/xlog_internal.h"
#include "storage/smgr.h"
{"XLOG", xlog_redo, xlog_undo, xlog_desc, NULL, NULL},
{"Transaction", xact_redo, xact_undo, xact_desc, NULL, NULL},
{"Storage", smgr_redo, smgr_undo, smgr_desc, NULL, NULL},
- {"SLRU", slru_redo, slru_undo, slru_desc, NULL, NULL},
+ {"CLOG", clog_redo, clog_undo, clog_desc, NULL, NULL},
{"Reserved 4", NULL, NULL, NULL, NULL, NULL},
{"Reserved 5", NULL, NULL, NULL, NULL, NULL},
{"Reserved 6", NULL, NULL, NULL, NULL, NULL},
* slru.c
* Simple LRU buffering for transaction status logfiles
*
- * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
- * Portions Copyright (c) 1994, Regents of the University of California
- *
- * $PostgreSQL: pgsql/src/backend/access/transam/slru.c,v 1.18 2004/07/21 22:31:20 tgl Exp $
- *
- *-------------------------------------------------------------------------
- */
-#include "postgres.h"
-
-#include <fcntl.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-#include "access/clog.h"
-#include "access/slru.h"
-#include "access/subtrans.h"
-#include "postmaster/bgwriter.h"
-#include "storage/fd.h"
-#include "storage/lwlock.h"
-#include "storage/shmem.h"
-#include "miscadmin.h"
-
-
-/*
- * Define segment size. A page is the same BLCKSZ as is used everywhere
- * else in Postgres. The segment size can be chosen somewhat arbitrarily;
- * we make it 32 pages by default, or 256Kb, i.e. 1M transactions for CLOG
- * or 64K transactions for SUBTRANS.
- *
- * Note: because TransactionIds are 32 bits and wrap around at 0xFFFFFFFF,
- * page numbering also wraps around at 0xFFFFFFFF/xxxx_XACTS_PER_PAGE (where
- * xxxx is CLOG or SUBTRANS, respectively), and segment numbering at
- * 0xFFFFFFFF/xxxx_XACTS_PER_PAGE/SLRU_PAGES_PER_SEGMENT. We need
- * take no explicit notice of that fact in this module, except when comparing
- * segment and page numbers in SimpleLruTruncate (see PagePrecedes()).
- */
-
-#define SLRU_PAGES_PER_SEGMENT 32
-
-
-/*----------
- * Shared-memory data structures for SLRU control
- *
* We use a simple least-recently-used scheme to manage a pool of page
* buffers. Under ordinary circumstances we expect that write
* traffic will occur mostly to the latest page (and to the just-prior
* to re-dirty a page that is currently being written out. This is handled
* by setting the page's state from WRITE_IN_PROGRESS to DIRTY. The writing
* process must notice this and not mark the page CLEAN when it's done.
- *----------
+ *
+ *
+ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * $PostgreSQL: pgsql/src/backend/access/transam/slru.c,v 1.19 2004/08/23 23:22:44 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
*/
+#include "postgres.h"
-typedef enum
-{
- SLRU_PAGE_EMPTY, /* buffer is not in use */
- SLRU_PAGE_READ_IN_PROGRESS, /* page is being read in */
- SLRU_PAGE_CLEAN, /* page is valid and not dirty */
- SLRU_PAGE_DIRTY, /* page is valid but needs write */
- SLRU_PAGE_WRITE_IN_PROGRESS /* page is being written out */
-} SlruPageStatus;
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
-/*
- * Shared-memory state
- */
-typedef struct SlruSharedData
-{
- LWLockId ControlLock;
+#include "access/slru.h"
+#include "access/xlog.h"
+#include "storage/fd.h"
+#include "storage/shmem.h"
+#include "miscadmin.h"
- /*
- * Info for each buffer slot. Page number is undefined when status is
- * EMPTY. lru_count is essentially the number of page switches since
- * last use of this page; the page with highest lru_count is the best
- * candidate to replace.
- */
- char *page_buffer[NUM_CLOG_BUFFERS];
- SlruPageStatus page_status[NUM_CLOG_BUFFERS];
- int page_number[NUM_CLOG_BUFFERS];
- unsigned int page_lru_count[NUM_CLOG_BUFFERS];
- LWLockId BufferLocks[NUM_CLOG_BUFFERS]; /* Per-buffer I/O locks */
- /*
- * latest_page_number is the page number of the current end of the
- * CLOG; this is not critical data, since we use it only to avoid
- * swapping out the latest page.
- */
- int latest_page_number;
-} SlruSharedData;
+/*
+ * Define segment size. A page is the same BLCKSZ as is used everywhere
+ * else in Postgres. The segment size can be chosen somewhat arbitrarily;
+ * we make it 32 pages by default, or 256Kb, i.e. 1M transactions for CLOG
+ * or 64K transactions for SUBTRANS.
+ *
+ * Note: because TransactionIds are 32 bits and wrap around at 0xFFFFFFFF,
+ * page numbering also wraps around at 0xFFFFFFFF/xxxx_XACTS_PER_PAGE (where
+ * xxxx is CLOG or SUBTRANS, respectively), and segment numbering at
+ * 0xFFFFFFFF/xxxx_XACTS_PER_PAGE/SLRU_PAGES_PER_SEGMENT. We need
+ * take no explicit notice of that fact in this module, except when comparing
+ * segment and page numbers in SimpleLruTruncate (see PagePrecedes()).
+ *
+ * Note: this file currently assumes that segment file names will be four
+ * hex digits. This sets a lower bound on the segment size (64K transactions
+ * for 32-bit TransactionIds).
+ */
+#define SLRU_PAGES_PER_SEGMENT 32
#define SlruFileName(ctl, path, seg) \
snprintf(path, MAXPGPATH, "%s/%04X", (ctl)->Dir, seg)
typedef struct SlruFlushData
{
int num_files; /* # files actually open */
- int fd[NUM_CLOG_BUFFERS]; /* their FD's */
- int segno[NUM_CLOG_BUFFERS]; /* their clog seg#s */
+ int fd[NUM_SLRU_BUFFERS]; /* their FD's */
+ int segno[NUM_SLRU_BUFFERS]; /* their log seg#s */
} SlruFlushData;
/*
do { \
if ((shared)->page_lru_count[slotno] != 0) { \
int iilru; \
- for (iilru = 0; iilru < NUM_CLOG_BUFFERS; iilru++) \
+ for (iilru = 0; iilru < NUM_SLRU_BUFFERS; iilru++) \
(shared)->page_lru_count[iilru]++; \
(shared)->page_lru_count[slotno] = 0; \
} \
SlruFlush fdata);
static void SlruReportIOError(SlruCtl ctl, int pageno, TransactionId xid);
static int SlruSelectLRUPage(SlruCtl ctl, int pageno);
-static bool SlruScanDirectory(SlruCtl ctl, int cutoffPage, bool doDeletions);
/*
int
SimpleLruShmemSize(void)
{
- return MAXALIGN(sizeof(SlruSharedData)) + BLCKSZ * NUM_CLOG_BUFFERS;
+ return BUFFERALIGN(sizeof(SlruSharedData)) + BLCKSZ * NUM_SLRU_BUFFERS;
}
void
-SimpleLruInit(SlruCtl ctl, const char *name, const char *subdir)
+SimpleLruInit(SlruCtl ctl, const char *name,
+ LWLockId ctllock, const char *subdir)
{
SlruShared shared;
bool found;
memset(shared, 0, sizeof(SlruSharedData));
- shared->ControlLock = LWLockAssign();
+ shared->ControlLock = ctllock;
- bufptr = (char *) shared + MAXALIGN(sizeof(SlruSharedData));
+ bufptr = (char *) shared + BUFFERALIGN(sizeof(SlruSharedData));
- for (slotno = 0; slotno < NUM_CLOG_BUFFERS; slotno++)
+ for (slotno = 0; slotno < NUM_SLRU_BUFFERS; slotno++)
{
shared->page_buffer[slotno] = bufptr;
shared->page_status[slotno] = SLRU_PAGE_EMPTY;
shared->page_lru_count[slotno] = 1;
- shared->BufferLocks[slotno] = LWLockAssign();
+ shared->buffer_locks[slotno] = LWLockAssign();
bufptr += BLCKSZ;
}
else
Assert(found);
- /* Initialize the unshared control struct */
+ /*
+ * Initialize the unshared control struct, including directory path.
+ * We assume caller set PagePrecedes.
+ */
ctl->shared = shared;
- ctl->ControlLock = shared->ControlLock;
-
- /* Initialize unshared copy of directory path */
+ ctl->do_fsync = true; /* default behavior */
snprintf(ctl->Dir, MAXPGPATH, "%s/%s", DataDir, subdir);
}
int
SimpleLruZeroPage(SlruCtl ctl, int pageno)
{
- int slotno;
SlruShared shared = ctl->shared;
+ int slotno;
/* Find a suitable buffer slot for the page */
slotno = SlruSelectLRUPage(ctl, pageno);
* The passed-in xid is used only for error reporting, and may be
* InvalidTransactionId if no specific xid is associated with the action.
*
- * Return value is the shared-buffer address of the page.
+ * Return value is the shared-buffer slot number now holding the page.
* The buffer's LRU access info is updated.
- * If forwrite is true, the buffer is marked as dirty.
*
* Control lock must be held at entry, and will be held at exit.
*/
-char *
-SimpleLruReadPage(SlruCtl ctl, int pageno, TransactionId xid, bool forwrite)
+int
+SimpleLruReadPage(SlruCtl ctl, int pageno, TransactionId xid)
{
SlruShared shared = ctl->shared;
{
/* otherwise, it's ready to use */
SlruRecentlyUsed(shared, slotno);
- if (forwrite)
- shared->page_status[slotno] = SLRU_PAGE_DIRTY;
- return shared->page_buffer[slotno];
+ return slotno;
}
}
else
/* Release shared lock, grab per-buffer lock instead */
LWLockRelease(shared->ControlLock);
- LWLockAcquire(shared->BufferLocks[slotno], LW_EXCLUSIVE);
+ LWLockAcquire(shared->buffer_locks[slotno], LW_EXCLUSIVE);
/*
* Check to see if someone else already did the read, or took the
if (shared->page_number[slotno] != pageno ||
shared->page_status[slotno] != SLRU_PAGE_READ_IN_PROGRESS)
{
- LWLockRelease(shared->BufferLocks[slotno]);
+ LWLockRelease(shared->buffer_locks[slotno]);
LWLockAcquire(shared->ControlLock, LW_EXCLUSIVE);
continue;
}
shared->page_status[slotno] = ok ? SLRU_PAGE_CLEAN : SLRU_PAGE_EMPTY;
- LWLockRelease(shared->BufferLocks[slotno]);
+ LWLockRelease(shared->buffer_locks[slotno]);
/* Now it's okay to ereport if we failed */
if (!ok)
SlruReportIOError(ctl, pageno, xid);
SlruRecentlyUsed(shared, slotno);
- if (forwrite)
- shared->page_status[slotno] = SLRU_PAGE_DIRTY;
- return shared->page_buffer[slotno];
+ return slotno;
}
}
void
SimpleLruWritePage(SlruCtl ctl, int slotno, SlruFlush fdata)
{
+ SlruShared shared = ctl->shared;
int pageno;
bool ok;
- SlruShared shared = ctl->shared;
/* Do nothing if page does not need writing */
if (shared->page_status[slotno] != SLRU_PAGE_DIRTY &&
/* Release shared lock, grab per-buffer lock instead */
LWLockRelease(shared->ControlLock);
- LWLockAcquire(shared->BufferLocks[slotno], LW_EXCLUSIVE);
+ LWLockAcquire(shared->buffer_locks[slotno], LW_EXCLUSIVE);
/*
* Check to see if someone else already did the write, or took the
(shared->page_status[slotno] != SLRU_PAGE_DIRTY &&
shared->page_status[slotno] != SLRU_PAGE_WRITE_IN_PROGRESS))
{
- LWLockRelease(shared->BufferLocks[slotno]);
+ LWLockRelease(shared->buffer_locks[slotno]);
LWLockAcquire(shared->ControlLock, LW_EXCLUSIVE);
return;
}
if (shared->page_status[slotno] == SLRU_PAGE_WRITE_IN_PROGRESS)
shared->page_status[slotno] = ok ? SLRU_PAGE_CLEAN : SLRU_PAGE_DIRTY;
- LWLockRelease(shared->BufferLocks[slotno]);
+ LWLockRelease(shared->buffer_locks[slotno]);
/* Now it's okay to ereport if we failed */
if (!ok)
*/
if (!fdata)
{
- if (pg_fsync(fd))
+ if (ctl->do_fsync && pg_fsync(fd))
{
slru_errcause = SLRU_FSYNC_FAILED;
slru_errno = errno;
unsigned int bestcount = 0;
/* See if page already has a buffer assigned */
- for (slotno = 0; slotno < NUM_CLOG_BUFFERS; slotno++)
+ for (slotno = 0; slotno < NUM_SLRU_BUFFERS; slotno++)
{
if (shared->page_number[slotno] == pageno &&
shared->page_status[slotno] != SLRU_PAGE_EMPTY)
* If we find any EMPTY slot, just select that one. Else locate
* the least-recently-used slot that isn't the latest page.
*/
- for (slotno = 0; slotno < NUM_CLOG_BUFFERS; slotno++)
+ for (slotno = 0; slotno < NUM_SLRU_BUFFERS; slotno++)
{
if (shared->page_status[slotno] == SLRU_PAGE_EMPTY)
return slotno;
*/
if (shared->page_status[bestslot] == SLRU_PAGE_READ_IN_PROGRESS)
(void) SimpleLruReadPage(ctl, shared->page_number[bestslot],
- InvalidTransactionId, false);
+ InvalidTransactionId);
else
SimpleLruWritePage(ctl, bestslot, NULL);
}
/*
- * This must be called ONCE during postmaster or standalone-backend startup
- */
-void
-SimpleLruSetLatestPage(SlruCtl ctl, int pageno)
-{
- SlruShared shared = ctl->shared;
-
- shared->latest_page_number = pageno;
-}
-
-/*
- * This is called during checkpoint and postmaster/standalone-backend shutdown
+ * Flush dirty pages to disk during checkpoint or database shutdown
*/
void
SimpleLruFlush(SlruCtl ctl, bool checkpoint)
int i;
bool ok;
+ /*
+ * Find and write dirty pages
+ */
fdata.num_files = 0;
LWLockAcquire(shared->ControlLock, LW_EXCLUSIVE);
- for (slotno = 0; slotno < NUM_CLOG_BUFFERS; slotno++)
+ for (slotno = 0; slotno < NUM_SLRU_BUFFERS; slotno++)
{
SimpleLruWritePage(ctl, slotno, &fdata);
ok = true;
for (i = 0; i < fdata.num_files; i++)
{
- if (pg_fsync(fdata.fd[i]))
+ if (ctl->do_fsync && pg_fsync(fdata.fd[i]))
{
slru_errcause = SLRU_FSYNC_FAILED;
slru_errno = errno;
/*
* Remove all segments before the one holding the passed page number
- *
- * When this is called, we know that the database logically contains no
- * reference to transaction IDs older than oldestXact. However, we must
- * not remove any segment until we have performed a checkpoint, to ensure
- * that no such references remain on disk either; else a crash just after
- * the truncation might leave us with a problem. Since CLOG segments hold
- * a large number of transactions, the opportunity to actually remove a
- * segment is fairly rare, and so it seems best not to do the checkpoint
- * unless we have confirmed that there is a removable segment. Therefore
- * we issue the checkpoint command here, not in higher-level code as might
- * seem cleaner.
*/
void
SimpleLruTruncate(SlruCtl ctl, int cutoffPage)
{
- int slotno;
SlruShared shared = ctl->shared;
+ int slotno;
/*
* The cutoff point is the start of the segment containing cutoffPage.
*/
cutoffPage -= cutoffPage % SLRU_PAGES_PER_SEGMENT;
- if (!SlruScanDirectory(ctl, cutoffPage, false))
- return; /* nothing to remove */
-
- /* Perform a CHECKPOINT */
- RequestCheckpoint(true);
-
/*
* Scan shared memory and remove any pages preceding the cutoff page,
- * to ensure we won't rewrite them later. (Any dirty pages should
- * have been flushed already during the checkpoint, we're just being
- * extra careful here.)
+ * to ensure we won't rewrite them later. (Since this is normally
+ * called in or just after a checkpoint, any dirty pages should
+ * have been flushed already ... we're just being extra careful here.)
*/
LWLockAcquire(shared->ControlLock, LW_EXCLUSIVE);
return;
}
- for (slotno = 0; slotno < NUM_CLOG_BUFFERS; slotno++)
+ for (slotno = 0; slotno < NUM_SLRU_BUFFERS; slotno++)
{
if (shared->page_status[slotno] == SLRU_PAGE_EMPTY)
continue;
*/
if (shared->page_status[slotno] == SLRU_PAGE_READ_IN_PROGRESS)
(void) SimpleLruReadPage(ctl, shared->page_number[slotno],
- InvalidTransactionId, false);
+ InvalidTransactionId);
else
SimpleLruWritePage(ctl, slotno, NULL);
goto restart;
}
/*
- * SlruTruncate subroutine: scan directory for removable segments.
+ * SimpleLruTruncate subroutine: scan directory for removable segments.
* Actually remove them iff doDeletions is true. Return TRUE iff any
* removable segments were found. Note: no locking is needed.
+ *
+ * This can be called directly from clog.c, for reasons explained there.
*/
-static bool
+bool
SlruScanDirectory(SlruCtl ctl, int cutoffPage, bool doDeletions)
{
bool found = false;
int segpage;
char path[MAXPGPATH];
+ /*
+ * The cutoff point is the start of the segment containing cutoffPage.
+ * (This is redundant when called from SimpleLruTruncate, but not when
+ * called directly from clog.c.)
+ */
+ cutoffPage -= cutoffPage % SLRU_PAGES_PER_SEGMENT;
+
cldir = AllocateDir(ctl->Dir);
if (cldir == NULL)
ereport(ERROR,
found = true;
if (doDeletions)
{
- ereport(LOG,
- (errmsg("removing file \"%s/%s\"",
- ctl->Dir, clde->d_name)));
snprintf(path, MAXPGPATH, "%s/%s", ctl->Dir, clde->d_name);
+ ereport(LOG,
+ (errmsg("removing file \"%s\"", path)));
unlink(path);
}
}
return found;
}
-
-/*
- * SLRU resource manager's routines
- */
-void
-slru_redo(XLogRecPtr lsn, XLogRecord *record)
-{
- uint8 info = record->xl_info & ~XLR_INFO_MASK;
- int pageno;
-
- memcpy(&pageno, XLogRecGetData(record), sizeof(int));
-
- switch (info)
- {
- case CLOG_ZEROPAGE:
- clog_zeropage_redo(pageno);
- break;
- case SUBTRANS_ZEROPAGE:
- subtrans_zeropage_redo(pageno);
- break;
- default:
- elog(PANIC, "slru_redo: unknown op code %u", info);
- }
-}
-
-void
-slru_undo(XLogRecPtr lsn, XLogRecord *record)
-{
-}
-
-void
-slru_desc(char *buf, uint8 xl_info, char *rec)
-{
- uint8 info = xl_info & ~XLR_INFO_MASK;
-
- if (info == CLOG_ZEROPAGE)
- {
- int pageno;
-
- memcpy(&pageno, rec, sizeof(int));
- sprintf(buf + strlen(buf), "clog zeropage: %d", pageno);
- }
- else if (info == SUBTRANS_ZEROPAGE)
- {
- int pageno;
-
- memcpy(&pageno, rec, sizeof(int));
- sprintf(buf + strlen(buf), "subtrans zeropage: %d", pageno);
- }
- else
- strcat(buf, "UNKNOWN");
-}
/*-------------------------------------------------------------------------
*
* subtrans.c
- * PostgreSQL subtrans-log manager
+ * PostgreSQL subtransaction-log manager
*
- * The pg_subtrans manager is a pg_clog-like manager which stores the parent
+ * The pg_subtrans manager is a pg_clog-like manager that stores the parent
* transaction Id for each transaction. It is a fundamental part of the
* nested transactions implementation. A main transaction has a parent
* of InvalidTransactionId, and each subtransaction has its immediate parent.
* The tree can easily be walked from child to parent, but not in the
* opposite direction.
*
- * This code is mostly derived from clog.c.
+ * This code is based on clog.c, but the robustness requirements
+ * are completely different from pg_clog, because we only need to remember
+ * pg_subtrans information for currently-open transactions. Thus, there is
+ * no need to preserve data over a crash and restart.
+ *
+ * There are no XLOG interactions since we do not care about preserving
+ * data across crashes. During database startup, we simply force the
+ * currently-active page of SUBTRANS to zeroes.
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/access/transam/subtrans.c,v 1.2 2004/08/22 02:41:57 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/subtrans.c,v 1.3 2004/08/23 23:22:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
-#include <fcntl.h>
-#include <dirent.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
#include "access/slru.h"
#include "access/subtrans.h"
-#include "miscadmin.h"
-#include "storage/lwlock.h"
+#include "storage/sinval.h"
#include "utils/tqual.h"
/*
- * Defines for SubTrans page and segment sizes. A page is the same BLCKSZ
- * as is used everywhere else in Postgres.
+ * Defines for SubTrans page sizes. A page is the same BLCKSZ as is used
+ * everywhere else in Postgres.
*
* Note: because TransactionIds are 32 bits and wrap around at 0xFFFFFFFF,
* SubTrans page numbering also wraps around at
* 0xFFFFFFFF/SUBTRANS_XACTS_PER_PAGE, and segment numbering at
* 0xFFFFFFFF/SUBTRANS_XACTS_PER_PAGE/SLRU_SEGMENTS_PER_PAGE. We need take no
* explicit notice of that fact in this module, except when comparing segment
- * and page numbers in TruncateSubTrans (see SubTransPagePrecedes).
+ * and page numbers in TruncateSUBTRANS (see SubTransPagePrecedes).
*/
/* We need four bytes per xact */
#define TransactionIdToEntry(xid) ((xid) % (TransactionId) SUBTRANS_XACTS_PER_PAGE)
-/*----------
- * Shared-memory data structures for SUBTRANS control
- *
- * XLOG interactions: this module generates an XLOG record whenever a new
- * SUBTRANS page is initialized to zeroes. Other writes of SUBTRANS come from
- * recording of transaction commit or abort in xact.c, which generates its
- * own XLOG records for these events and will re-perform the status update
- * on redo; so we need make no additional XLOG entry here. Also, the XLOG
- * is guaranteed flushed through the XLOG commit record before we are called
- * to log a commit, so the WAL rule "write xlog before data" is satisfied
- * automatically for commits, and we don't really care for aborts. Therefore,
- * we don't need to mark SUBTRANS pages with LSN information; we have enough
- * synchronization already.
- *----------
+/*
+ * Link to shared-memory data structures for SUBTRANS control
*/
-
-
static SlruCtlData SubTransCtlData;
-static SlruCtl SubTransCtl = &SubTransCtlData;
+#define SubTransCtl (&SubTransCtlData)
-static int ZeroSUBTRANSPage(int pageno, bool writeXlog);
+static int ZeroSUBTRANSPage(int pageno);
static bool SubTransPagePrecedes(int page1, int page2);
-static void WriteZeroPageXlogRec(int pageno);
/*
{
int pageno = TransactionIdToPage(xid);
int entryno = TransactionIdToEntry(xid);
+ int slotno;
TransactionId *ptr;
- LWLockAcquire(SubTransCtl->ControlLock, LW_EXCLUSIVE);
+ LWLockAcquire(SubtransControlLock, LW_EXCLUSIVE);
- ptr = (TransactionId *) SimpleLruReadPage(SubTransCtl, pageno, xid, true);
+ slotno = SimpleLruReadPage(SubTransCtl, pageno, xid);
+ ptr = (TransactionId *) SubTransCtl->shared->page_buffer[slotno];
ptr += entryno;
- /* Current state should be 0 or target state */
- Assert(*ptr == InvalidTransactionId || *ptr == parent);
+ /* Current state should be 0 */
+ Assert(*ptr == InvalidTransactionId);
*ptr = parent;
- /* ...->page_status[slotno] = SLRU_PAGE_DIRTY; already done */
+ SubTransCtl->shared->page_status[slotno] = SLRU_PAGE_DIRTY;
- LWLockRelease(SubTransCtl->ControlLock);
+ LWLockRelease(SubtransControlLock);
}
/*
{
int pageno = TransactionIdToPage(xid);
int entryno = TransactionIdToEntry(xid);
+ int slotno;
TransactionId *ptr;
TransactionId parent;
if (!TransactionIdIsNormal(xid))
return InvalidTransactionId;
- LWLockAcquire(SubTransCtl->ControlLock, LW_EXCLUSIVE);
+ LWLockAcquire(SubtransControlLock, LW_EXCLUSIVE);
- ptr = (TransactionId *) SimpleLruReadPage(SubTransCtl, pageno, xid, false);
+ slotno = SimpleLruReadPage(SubTransCtl, pageno, xid);
+ ptr = (TransactionId *) SubTransCtl->shared->page_buffer[slotno];
ptr += entryno;
parent = *ptr;
- LWLockRelease(SubTransCtl->ControlLock);
+ LWLockRelease(SubtransControlLock);
return parent;
}
/*
- * Initialization of shared memory for Subtrans
+ * Initialization of shared memory for SUBTRANS
*/
int
void
SUBTRANSShmemInit(void)
{
- SimpleLruInit(SubTransCtl, "SUBTRANS Ctl", "pg_subtrans");
SubTransCtl->PagePrecedes = SubTransPagePrecedes;
+ SimpleLruInit(SubTransCtl, "SUBTRANS Ctl",
+ SubtransControlLock, "pg_subtrans");
+ /* Override default assumption that writes should be fsync'd */
+ SubTransCtl->do_fsync = false;
}
/*
* This func must be called ONCE on system install. It creates
- * the initial SubTrans segment. (The SubTrans directory is assumed to
- * have been created by initdb, and SubTransShmemInit must have been called
- * already.)
+ * the initial SUBTRANS segment. (The SUBTRANS directory is assumed to
+ * have been created by the initdb shell script, and SUBTRANSShmemInit
+ * must have been called already.)
+ *
+ * Note: it's not really necessary to create the initial segment now,
+ * since slru.c would create it on first write anyway. But we may as well
+ * do it to be sure the directory is set up correctly.
*/
void
BootStrapSUBTRANS(void)
{
int slotno;
- LWLockAcquire(SubTransCtl->ControlLock, LW_EXCLUSIVE);
+ LWLockAcquire(SubtransControlLock, LW_EXCLUSIVE);
- /* Create and zero the first page of the commit log */
- slotno = ZeroSUBTRANSPage(0, false);
+ /* Create and zero the first page of the subtrans log */
+ slotno = ZeroSUBTRANSPage(0);
/* Make sure it's written out */
SimpleLruWritePage(SubTransCtl, slotno, NULL);
- /* Assert(SubTransCtl->page_status[slotno] == SLRU_PAGE_CLEAN); */
+ Assert(SubTransCtl->shared->page_status[slotno] == SLRU_PAGE_CLEAN);
- LWLockRelease(SubTransCtl->ControlLock);
+ LWLockRelease(SubtransControlLock);
}
/*
- * Initialize (or reinitialize) a page of SubTrans to zeroes.
- * If writeXlog is TRUE, also emit an XLOG record saying we did this.
+ * Initialize (or reinitialize) a page of SUBTRANS to zeroes.
*
* The page is not actually written, just set up in shared memory.
* The slot number of the new page is returned.
* Control lock must be held at entry, and will be held at exit.
*/
static int
-ZeroSUBTRANSPage(int pageno, bool writeXlog)
+ZeroSUBTRANSPage(int pageno)
{
- int slotno = SimpleLruZeroPage(SubTransCtl, pageno);
-
- if (writeXlog)
- WriteZeroPageXlogRec(pageno);
-
- return slotno;
+ return SimpleLruZeroPage(SubTransCtl, pageno);
}
/*
void
StartupSUBTRANS(void)
{
+ int startPage;
+
/*
- * Initialize our idea of the latest page number.
+ * Since we don't expect pg_subtrans to be valid across crashes,
+ * we initialize the currently-active page to zeroes during startup.
+ * Whenever we advance into a new page, ExtendSUBTRANS will likewise
+ * zero the new page without regard to whatever was previously on disk.
*/
- SimpleLruSetLatestPage(SubTransCtl,
- TransactionIdToPage(ShmemVariableCache->nextXid));
+ LWLockAcquire(SubtransControlLock, LW_EXCLUSIVE);
+
+ startPage = TransactionIdToPage(ShmemVariableCache->nextXid);
+ (void) ZeroSUBTRANSPage(startPage);
+
+ LWLockRelease(SubtransControlLock);
}
/*
void
ShutdownSUBTRANS(void)
{
+ /*
+ * Flush dirty SUBTRANS pages to disk
+ *
+ * This is not actually necessary from a correctness point of view.
+ * We do it merely as a debugging aid.
+ */
SimpleLruFlush(SubTransCtl, false);
}
void
CheckPointSUBTRANS(void)
{
+ /*
+ * Flush dirty SUBTRANS pages to disk
+ *
+ * This is not actually necessary from a correctness point of view.
+ * We do it merely to improve the odds that writing of dirty pages is done
+ * by the checkpoint process and not by backends.
+ */
SimpleLruFlush(SubTransCtl, true);
}
/*
- * Make sure that SubTrans has room for a newly-allocated XID.
+ * Make sure that SUBTRANS has room for a newly-allocated XID.
*
* NB: this is called while holding XidGenLock. We want it to be very fast
* most of the time; even when it's not so fast, no actual I/O need happen
- * unless we're forced to write out a dirty subtrans or xlog page to make room
+ * unless we're forced to write out a dirty subtrans page to make room
* in shared memory.
*/
void
pageno = TransactionIdToPage(newestXact);
- LWLockAcquire(SubTransCtl->ControlLock, LW_EXCLUSIVE);
+ LWLockAcquire(SubtransControlLock, LW_EXCLUSIVE);
- /* Zero the page and make an XLOG entry about it */
- ZeroSUBTRANSPage(pageno, true);
+ /* Zero the page */
+ ZeroSUBTRANSPage(pageno);
- LWLockRelease(SubTransCtl->ControlLock);
+ LWLockRelease(SubtransControlLock);
}
/*
- * Remove all SubTrans segments before the one holding the passed transaction ID
+ * Remove all SUBTRANS segments before the one holding the passed transaction ID
*
- * When this is called, we know that the database logically contains no
- * reference to transaction IDs older than oldestXact. However, we must
- * not truncate the SubTrans until we have performed a checkpoint, to ensure
- * that no such references remain on disk either; else a crash just after
- * the truncation might leave us with a problem. Since SubTrans segments hold
- * a large number of transactions, the opportunity to actually remove a
- * segment is fairly rare, and so it seems best not to do the checkpoint
- * unless we have confirmed that there is a removable segment. Therefore
- * we issue the checkpoint command here, not in higher-level code as might
- * seem cleaner.
+ * This is normally called during checkpoint, with oldestXact being the
+ * oldest XMIN of any running transaction.
*/
void
TruncateSUBTRANS(TransactionId oldestXact)
* We pass the *page* containing oldestXact to SimpleLruTruncate.
*/
cutoffPage = TransactionIdToPage(oldestXact);
+
SimpleLruTruncate(SubTransCtl, cutoffPage);
}
/*
- * Decide which of two SubTrans page numbers is "older" for truncation purposes.
+ * Decide which of two SUBTRANS page numbers is "older" for truncation purposes.
*
* We need to use comparison of TransactionIds here in order to do the right
* thing with wraparound XID arithmetic. However, if we are asked about
return TransactionIdPrecedes(xid1, xid2);
}
-
-
-/*
- * 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)
-{
- XLogRecData rdata;
-
- rdata.buffer = InvalidBuffer;
- rdata.data = (char *) (&pageno);
- rdata.len = sizeof(int);
- rdata.next = NULL;
- (void) XLogInsert(RM_SLRU_ID, SUBTRANS_ZEROPAGE | XLOG_NO_TRAN, &rdata);
-}
-
-/* Redo a ZEROPAGE action during WAL replay */
-void
-subtrans_zeropage_redo(int pageno)
-{
- int slotno;
-
- LWLockAcquire(SubTransCtl->ControlLock, LW_EXCLUSIVE);
-
- slotno = ZeroSUBTRANSPage(pageno, false);
- SimpleLruWritePage(SubTransCtl, slotno, NULL);
- /* Assert(SubTransCtl->page_status[slotno] == SLRU_PAGE_CLEAN); */
-
- LWLockRelease(SubTransCtl->ControlLock);
-}
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.162 2004/08/12 19:03:23 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.163 2004/08/23 23:22:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
if (!shutdown)
PreallocXlogFiles(recptr);
+ /*
+ * Truncate pg_subtrans if possible. We can throw away all data before
+ * the oldest XMIN of any running transaction. No future transaction will
+ * attempt to reference any pg_subtrans entry older than that (see Asserts
+ * in subtrans.c).
+ */
+ TruncateSUBTRANS(GetOldestXmin(true));
+
LWLockRelease(CheckpointLock);
}
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.286 2004/08/06 04:15:07 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.287 2004/08/23 23:22:45 tgl Exp $
*
*-------------------------------------------------------------------------
*/
return;
}
- /* Truncate CLOG and SUBTRANS to the oldest vacuumxid */
+ /* Truncate CLOG to the oldest vacuumxid */
TruncateCLOG(vacuumXID);
- TruncateSUBTRANS(vacuumXID);
/* Give warning about impending wraparound problems */
if (frozenAlreadyWrapped)
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/ipc/sinval.c,v 1.69 2004/08/22 02:41:57 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/ipc/sinval.c,v 1.70 2004/08/23 23:22:45 tgl Exp $
*
*-------------------------------------------------------------------------
*/
* FALSE is sufficient for non-shared relations, since only backends in my
* own database could ever see the tuples in them.
*
+ * This is also used to determine where to truncate pg_subtrans. allDbs
+ * must be TRUE for that case.
+ *
* Note: we include the 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.
TransactionId result;
int index;
- result = GetTopTransactionId();
+ /*
+ * 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!)
+ */
+ if (IsTransactionState())
+ result = GetTopTransactionId();
+ else
+ result = ReadNewTransactionId();
LWLockAcquire(SInvalLock, LW_SHARED);
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/lmgr/lwlock.c,v 1.21 2004/07/01 00:50:59 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/lmgr/lwlock.c,v 1.22 2004/08/23 23:22:45 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
-#include "access/clog.h"
-#include "access/subtrans.h"
+#include "access/slru.h"
#include "storage/lwlock.h"
#include "storage/proc.h"
#include "storage/spin.h"
/* bufmgr.c needs two for each shared buffer */
numLocks += 2 * NBuffers;
- /* clog.c needs one per CLOG buffer + one control lock */
- numLocks += NUM_CLOG_BUFFERS + 1;
+ /* clog.c needs one per CLOG buffer */
+ numLocks += NUM_SLRU_BUFFERS;
- /* subtrans.c needs one per SubTrans buffer + one control lock */
- numLocks += NUM_SUBTRANS_BUFFERS + 1;
+ /* subtrans.c needs one per SubTrans buffer */
+ numLocks += NUM_SLRU_BUFFERS;
/* Perhaps create a few more for use by user-defined modules? */
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/access/clog.h,v 1.9 2004/07/01 00:51:38 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/clog.h,v 1.10 2004/08/23 23:22:45 tgl Exp $
*/
#ifndef CLOG_H
#define CLOG_H
#define TRANSACTION_STATUS_ABORTED 0x02
#define TRANSACTION_STATUS_SUB_COMMITTED 0x03
-/* exported because lwlock.c needs it */
-#define NUM_CLOG_BUFFERS 8
-
extern void TransactionIdSetStatus(TransactionId xid, XidStatus status);
extern XidStatus TransactionIdGetStatus(TransactionId xid);
extern void CheckPointCLOG(void);
extern void ExtendCLOG(TransactionId newestXact);
extern void TruncateCLOG(TransactionId oldestXact);
-extern void clog_zeropage_redo(int pageno);
+
+/* XLOG stuff */
+#define CLOG_ZEROPAGE 0x00
+
+extern void clog_redo(XLogRecPtr lsn, XLogRecord *record);
+extern void clog_undo(XLogRecPtr lsn, XLogRecord *record);
+extern void clog_desc(char *buf, uint8 xl_info, char *rec);
#endif /* CLOG_H */
*
* Resource managers definition
*
- * $PostgreSQL: pgsql/src/include/access/rmgr.h,v 1.11 2004/07/01 00:51:38 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/rmgr.h,v 1.12 2004/08/23 23:22:45 tgl Exp $
*/
#ifndef RMGR_H
#define RMGR_H
#define RM_XLOG_ID 0
#define RM_XACT_ID 1
#define RM_SMGR_ID 2
-#define RM_SLRU_ID 3
+#define RM_CLOG_ID 3
#define RM_HEAP_ID 10
#define RM_BTREE_ID 11
#define RM_HASH_ID 12
-/*
- * slru.h
+/*-------------------------------------------------------------------------
*
- * Simple LRU
+ * slru.h
+ * Simple LRU buffering for transaction status logfiles
*
- * Portions Copyright (c) 2003, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/access/slru.h,v 1.7 2004/07/01 00:51:38 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/slru.h,v 1.8 2004/08/23 23:22:45 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
*/
#ifndef SLRU_H
#define SLRU_H
-#include "access/xlog.h"
#include "storage/lwlock.h"
-/* Opaque structs known only in slru.c */
-typedef struct SlruSharedData *SlruShared;
-typedef struct SlruFlushData *SlruFlush;
+/*
+ * Number of page buffers. Ideally this could be different for CLOG and
+ * SUBTRANS, but the benefit doesn't seem to be worth any additional
+ * notational cruft.
+ */
+#define NUM_SLRU_BUFFERS 8
+
+/* Page status codes */
+typedef enum
+{
+ SLRU_PAGE_EMPTY, /* buffer is not in use */
+ SLRU_PAGE_READ_IN_PROGRESS, /* page is being read in */
+ SLRU_PAGE_CLEAN, /* page is valid and not dirty */
+ SLRU_PAGE_DIRTY, /* page is valid but needs write */
+ SLRU_PAGE_WRITE_IN_PROGRESS /* page is being written out */
+} SlruPageStatus;
+
+/*
+ * Shared-memory state
+ */
+typedef struct SlruSharedData
+{
+ LWLockId ControlLock;
+
+ /*
+ * Info for each buffer slot. Page number is undefined when status is
+ * EMPTY. lru_count is essentially the number of page switches since
+ * last use of this page; the page with highest lru_count is the best
+ * candidate to replace.
+ */
+ char *page_buffer[NUM_SLRU_BUFFERS];
+ SlruPageStatus page_status[NUM_SLRU_BUFFERS];
+ int page_number[NUM_SLRU_BUFFERS];
+ unsigned int page_lru_count[NUM_SLRU_BUFFERS];
+ LWLockId buffer_locks[NUM_SLRU_BUFFERS];
+
+ /*
+ * latest_page_number is the page number of the current end of the
+ * log; this is not critical data, since we use it only to avoid
+ * swapping out the latest page.
+ */
+ int latest_page_number;
+} SlruSharedData;
+
+typedef SlruSharedData *SlruShared;
/*
* SlruCtlData is an unshared structure that points to the active information
{
SlruShared shared;
- LWLockId ControlLock;
-
/*
- * Dir is set during SimpleLruInit and does not change thereafter.
- * Since it's always the same, it doesn't need to be in shared memory.
+ * This flag tells whether to fsync writes (true for pg_clog,
+ * false for pg_subtrans).
*/
- char Dir[MAXPGPATH];
+ bool do_fsync;
/*
* Decide which of two page numbers is "older" for truncation purposes.
*/
bool (*PagePrecedes) (int, int);
+ /*
+ * Dir is set during SimpleLruInit and does not change thereafter.
+ * Since it's always the same, it doesn't need to be in shared memory.
+ */
+ char Dir[MAXPGPATH];
} SlruCtlData;
typedef SlruCtlData *SlruCtl;
+/* Opaque struct known only in slru.c */
+typedef struct SlruFlushData *SlruFlush;
+
extern int SimpleLruShmemSize(void);
-extern void SimpleLruInit(SlruCtl ctl, const char *name, const char *subdir);
+extern void SimpleLruInit(SlruCtl ctl, const char *name,
+ LWLockId ctllock, const char *subdir);
extern int SimpleLruZeroPage(SlruCtl ctl, int pageno);
-extern char *SimpleLruReadPage(SlruCtl ctl, int pageno,
- TransactionId xid, bool forwrite);
+extern int SimpleLruReadPage(SlruCtl ctl, int pageno, TransactionId xid);
extern void SimpleLruWritePage(SlruCtl ctl, int slotno, SlruFlush fdata);
-extern void SimpleLruSetLatestPage(SlruCtl ctl, int pageno);
extern void SimpleLruFlush(SlruCtl ctl, bool checkpoint);
extern void SimpleLruTruncate(SlruCtl ctl, int cutoffPage);
-
-/* XLOG stuff */
-#define CLOG_ZEROPAGE 0x00
-#define SUBTRANS_ZEROPAGE 0x10
-
-extern void slru_redo(XLogRecPtr lsn, XLogRecord *record);
-extern void slru_undo(XLogRecPtr lsn, XLogRecord *record);
-extern void slru_desc(char *buf, uint8 xl_info, char *rec);
+extern bool SlruScanDirectory(SlruCtl ctl, int cutoffPage, bool doDeletions);
#endif /* SLRU_H */
/*
* subtrans.h
*
- * PostgreSQL subtrans-log manager
+ * PostgreSQL subtransaction-log manager
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/access/subtrans.h,v 1.2 2004/08/22 02:41:58 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/subtrans.h,v 1.3 2004/08/23 23:22:45 tgl Exp $
*/
#ifndef SUBTRANS_H
#define SUBTRANS_H
-#include "access/xlog.h"
-
-/* exported because lwlock.c needs it */
-/* cannot be different from NUM_CLOG_BUFFERS without slru.c changes */
-#define NUM_SUBTRANS_BUFFERS NUM_CLOG_BUFFERS
-
extern void SubTransSetParent(TransactionId xid, TransactionId parent);
extern TransactionId SubTransGetParent(TransactionId xid);
extern TransactionId SubTransGetTopmostTransaction(TransactionId xid);
extern void CheckPointSUBTRANS(void);
extern void ExtendSUBTRANS(TransactionId newestXact);
extern void TruncateSUBTRANS(TransactionId oldestXact);
-extern void subtrans_zeropage_redo(int pageno);
#endif /* SUBTRANS_H */
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/storage/lwlock.h,v 1.13 2004/08/11 04:07:16 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/lwlock.h,v 1.14 2004/08/23 23:22:45 tgl Exp $
*
*-------------------------------------------------------------------------
*/
ControlFileLock,
CheckpointLock,
CheckpointStartLock,
+ CLogControlLock,
+ SubtransControlLock,
RelCacheInitLock,
BgWriterCommLock,
projects / users / rhaas / postgres.git / commitdiff