Make pg_waldump report more detail information about PREPARE TRANSACTION record.

This commit changes xact_desc() so that it reports the detail information about
PREPARE TRANSACTION record, like GID (global transaction identifier),
timestamp at prepare transaction, delete-on-abort/commit relations,
XID of subtransactions, and invalidation messages. These are helpful
when diagnosing 2PC-related troubles.

Author: Fujii Masao
Reviewed-by: Michael Paquier, Andrey Lepikhov, Kyotaro Horiguchi, Julien Rouhaud, Alvaro Herrera
Discussion: https://postgr.es/m/CAHGQGwEvhASad4JJnCv=0dW2TJypZgW_Vpb-oZik2a3utCqcrA@mail.gmail.com

diff --git a/src/backend/access/rmgrdesc/standbydesc.c b/src/backend/access/rmgrdesc/standbydesc.c
index c295358f3646ee971c48a165c5062a1b546d5886..aaff652aebcdaae138dddcff04a9af460b806a77 100644 (file)
--- a/src/backend/access/rmgrdesc/standbydesc.c
+++ b/src/backend/access/rmgrdesc/standbydesc.c
@@ -102,6 +102,10 @@ standby_desc_invalidations(StringInfo buf,
 {
        int                     i;
 
+       /* Do nothing if there are no invalidation messages */
+       if (nmsgs <= 0)
+               return;
+
        if (relcacheInitFileInval)
                appendStringInfo(buf, "; relcache init file inval dbid %u tsid %u",
                                                 dbId, tsId);

diff --git a/src/backend/access/rmgrdesc/xactdesc.c b/src/backend/access/rmgrdesc/xactdesc.c
index a61f38dd19b23bda767bd1ab88250eebfb362c68..4c411c5322e4d3a2cac4178f656bce701e6deb26 100644 (file)
--- a/src/backend/access/rmgrdesc/xactdesc.c
+++ b/src/backend/access/rmgrdesc/xactdesc.c
@@ -209,43 +209,95 @@ ParseAbortRecord(uint8 info, xl_xact_abort *xlrec, xl_xact_parsed_abort *parsed)
        }
 }
 
-static void
-xact_desc_commit(StringInfo buf, uint8 info, xl_xact_commit *xlrec, RepOriginId origin_id)
+/*
+ * ParsePrepareRecord
+ */
+void
+ParsePrepareRecord(uint8 info, xl_xact_prepare *xlrec, xl_xact_parsed_prepare *parsed)
 {
-       xl_xact_parsed_commit parsed;
-       int                     i;
+       char       *bufptr;
 
-       ParseCommitRecord(info, xlrec, &parsed);
+       bufptr = ((char *) xlrec) + MAXALIGN(sizeof(xl_xact_prepare));
 
-       /* If this is a prepared xact, show the xid of the original xact */
-       if (TransactionIdIsValid(parsed.twophase_xid))
-               appendStringInfo(buf, "%u: ", parsed.twophase_xid);
+       memset(parsed, 0, sizeof(*parsed));
 
-       appendStringInfoString(buf, timestamptz_to_str(xlrec->xact_time));
+       parsed->xact_time = xlrec->prepared_at;
+       parsed->origin_lsn = xlrec->origin_lsn;
+       parsed->origin_timestamp = xlrec->origin_timestamp;
+       parsed->twophase_xid = xlrec->xid;
+       parsed->dbId = xlrec->database;
+       parsed->nsubxacts = xlrec->nsubxacts;
+       parsed->nrels = xlrec->ncommitrels;
+       parsed->nabortrels = xlrec->nabortrels;
+       parsed->nmsgs = xlrec->ninvalmsgs;
+
+       strncpy(parsed->twophase_gid, bufptr, xlrec->gidlen);
+       bufptr += MAXALIGN(xlrec->gidlen);
+
+       parsed->subxacts = (TransactionId *) bufptr;
+       bufptr += MAXALIGN(xlrec->nsubxacts * sizeof(TransactionId));
+
+       parsed->xnodes = (RelFileNode *) bufptr;
+       bufptr += MAXALIGN(xlrec->ncommitrels * sizeof(RelFileNode));
+
+       parsed->abortnodes = (RelFileNode *) bufptr;
+       bufptr += MAXALIGN(xlrec->nabortrels * sizeof(RelFileNode));
 
-       if (parsed.nrels > 0)
+       parsed->msgs = (SharedInvalidationMessage *) bufptr;
+       bufptr += MAXALIGN(xlrec->ninvalmsgs * sizeof(SharedInvalidationMessage));
+}
+
+static void
+xact_desc_relations(StringInfo buf, char *label, int nrels,
+                                       RelFileNode *xnodes)
+{
+       int             i;
+
+       if (nrels > 0)
        {
-               appendStringInfoString(buf, "; rels:");
-               for (i = 0; i < parsed.nrels; i++)
+               appendStringInfo(buf, "; %s:", label);
+               for (i = 0; i < nrels; i++)
                {
-                       char       *path = relpathperm(parsed.xnodes[i], MAIN_FORKNUM);
+                       char       *path = relpathperm(xnodes[i], MAIN_FORKNUM);
 
                        appendStringInfo(buf, " %s", path);
                        pfree(path);
                }
        }
-       if (parsed.nsubxacts > 0)
+}
+
+static void
+xact_desc_subxacts(StringInfo buf, int nsubxacts, TransactionId *subxacts)
+{
+       int             i;
+
+       if (nsubxacts > 0)
        {
                appendStringInfoString(buf, "; subxacts:");
-               for (i = 0; i < parsed.nsubxacts; i++)
-                       appendStringInfo(buf, " %u", parsed.subxacts[i]);
-       }
-       if (parsed.nmsgs > 0)
-       {
-               standby_desc_invalidations(
-                                                                  buf, parsed.nmsgs, parsed.msgs, parsed.dbId, parsed.tsId,
-                                                                  XactCompletionRelcacheInitFileInval(parsed.xinfo));
+               for (i = 0; i < nsubxacts; i++)
+                       appendStringInfo(buf, " %u", subxacts[i]);
        }
+}
+
+static void
+xact_desc_commit(StringInfo buf, uint8 info, xl_xact_commit *xlrec, RepOriginId origin_id)
+{
+       xl_xact_parsed_commit parsed;
+
+       ParseCommitRecord(info, xlrec, &parsed);
+
+       /* If this is a prepared xact, show the xid of the original xact */
+       if (TransactionIdIsValid(parsed.twophase_xid))
+               appendStringInfo(buf, "%u: ", parsed.twophase_xid);
+
+       appendStringInfoString(buf, timestamptz_to_str(xlrec->xact_time));
+
+       xact_desc_relations(buf, "rels", parsed.nrels, parsed.xnodes);
+       xact_desc_subxacts(buf, parsed.nsubxacts, parsed.subxacts);
+
+       standby_desc_invalidations(
+                                               buf, parsed.nmsgs, parsed.msgs, parsed.dbId, parsed.tsId,
+                                               XactCompletionRelcacheInitFileInval(parsed.xinfo));
 
        if (XactCompletionForceSyncCommit(parsed.xinfo))
                appendStringInfoString(buf, "; sync");
@@ -264,7 +316,6 @@ static void
 xact_desc_abort(StringInfo buf, uint8 info, xl_xact_abort *xlrec)
 {
        xl_xact_parsed_abort parsed;
-       int                     i;
 
        ParseAbortRecord(info, xlrec, &parsed);
 
@@ -273,24 +324,29 @@ xact_desc_abort(StringInfo buf, uint8 info, xl_xact_abort *xlrec)
                appendStringInfo(buf, "%u: ", parsed.twophase_xid);
 
        appendStringInfoString(buf, timestamptz_to_str(xlrec->xact_time));
-       if (parsed.nrels > 0)
-       {
-               appendStringInfoString(buf, "; rels:");
-               for (i = 0; i < parsed.nrels; i++)
-               {
-                       char       *path = relpathperm(parsed.xnodes[i], MAIN_FORKNUM);
 
-                       appendStringInfo(buf, " %s", path);
-                       pfree(path);
-               }
-       }
+       xact_desc_relations(buf, "rels", parsed.nrels, parsed.xnodes);
+       xact_desc_subxacts(buf, parsed.nsubxacts, parsed.subxacts);
+}
 
-       if (parsed.nsubxacts > 0)
-       {
-               appendStringInfoString(buf, "; subxacts:");
-               for (i = 0; i < parsed.nsubxacts; i++)
-                       appendStringInfo(buf, " %u", parsed.subxacts[i]);
-       }
+static void
+xact_desc_prepare(StringInfo buf, uint8 info, xl_xact_prepare *xlrec)
+{
+       xl_xact_parsed_prepare parsed;
+
+       ParsePrepareRecord(info, xlrec, &parsed);
+
+       appendStringInfo(buf, "gid %s: ", parsed.twophase_gid);
+       appendStringInfoString(buf, timestamptz_to_str(parsed.xact_time));
+
+       xact_desc_relations(buf, "rels(commit)", parsed.nrels, parsed.xnodes);
+       xact_desc_relations(buf, "rels(abort)", parsed.nabortrels,
+                                               parsed.abortnodes);
+       xact_desc_subxacts(buf, parsed.nsubxacts, parsed.subxacts);
+
+       standby_desc_invalidations(
+                                               buf, parsed.nmsgs, parsed.msgs, parsed.dbId, parsed.tsId,
+                                               xlrec->initfileinval);
 }
 
 static void
@@ -323,6 +379,12 @@ xact_desc(StringInfo buf, XLogReaderState *record)
 
                xact_desc_abort(buf, XLogRecGetInfo(record), xlrec);
        }
+       else if (info == XLOG_XACT_PREPARE)
+       {
+               xl_xact_prepare *xlrec = (xl_xact_prepare *) rec;
+
+               xact_desc_prepare(buf, XLogRecGetInfo(record), xlrec);
+       }
        else if (info == XLOG_XACT_ASSIGNMENT)
        {
                xl_xact_assignment *xlrec = (xl_xact_assignment *) rec;

diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index 712e842b9048d22df139147102da84374cdf786e..b3ad0d08e30f85d5b09147cc45ed792598bb0a88 100644 (file)
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -910,23 +910,7 @@ TwoPhaseGetDummyProc(TransactionId xid, bool lock_held)
  */
 #define TWOPHASE_MAGIC 0x57F94534      /* format identifier */
 
-typedef struct TwoPhaseFileHeader
-{
-       uint32          magic;                  /* format identifier */
-       uint32          total_len;              /* actual file length */
-       TransactionId xid;                      /* original transaction XID */
-       Oid                     database;               /* OID of database it was in */
-       TimestampTz prepared_at;        /* time of preparation */
-       Oid                     owner;                  /* user running the transaction */
-       int32           nsubxacts;              /* number of following subxact XIDs */
-       int32           ncommitrels;    /* number of delete-on-commit rels */
-       int32           nabortrels;             /* number of delete-on-abort rels */
-       int32           ninvalmsgs;             /* number of cache invalidation messages */
-       bool            initfileinval;  /* does relcache init file need invalidation? */
-       uint16          gidlen;                 /* length of the GID - GID follows the header */
-       XLogRecPtr      origin_lsn;             /* lsn of this record at origin node */
-       TimestampTz origin_timestamp;   /* time of prepare at origin node */
-} TwoPhaseFileHeader;
+typedef xl_xact_prepare TwoPhaseFileHeader;
 
 /*
  * Header for each record in a state file
@@ -1331,44 +1315,6 @@ ReadTwoPhaseFile(TransactionId xid, bool missing_ok)
        return buf;
 }
 
-/*
- * ParsePrepareRecord
- */
-void
-ParsePrepareRecord(uint8 info, char *xlrec, xl_xact_parsed_prepare *parsed)
-{
-       TwoPhaseFileHeader *hdr;
-       char       *bufptr;
-
-       hdr = (TwoPhaseFileHeader *) xlrec;
-       bufptr = xlrec + MAXALIGN(sizeof(TwoPhaseFileHeader));
-
-       parsed->origin_lsn = hdr->origin_lsn;
-       parsed->origin_timestamp = hdr->origin_timestamp;
-       parsed->twophase_xid = hdr->xid;
-       parsed->dbId = hdr->database;
-       parsed->nsubxacts = hdr->nsubxacts;
-       parsed->nrels = hdr->ncommitrels;
-       parsed->nabortrels = hdr->nabortrels;
-       parsed->nmsgs = hdr->ninvalmsgs;
-
-       strncpy(parsed->twophase_gid, bufptr, hdr->gidlen);
-       bufptr += MAXALIGN(hdr->gidlen);
-
-       parsed->subxacts = (TransactionId *) bufptr;
-       bufptr += MAXALIGN(hdr->nsubxacts * sizeof(TransactionId));
-
-       parsed->xnodes = (RelFileNode *) bufptr;
-       bufptr += MAXALIGN(hdr->ncommitrels * sizeof(RelFileNode));
-
-       parsed->abortnodes = (RelFileNode *) bufptr;
-       bufptr += MAXALIGN(hdr->nabortrels * sizeof(RelFileNode));
-
-       parsed->msgs = (SharedInvalidationMessage *) bufptr;
-       bufptr += MAXALIGN(hdr->ninvalmsgs * sizeof(SharedInvalidationMessage));
-}
-
-
 
 /*
  * Reads 2PC data from xlog. During checkpoint this data will be moved to

diff --git a/src/include/access/twophase.h b/src/include/access/twophase.h
index b9a531c96e3eb48ccf6c6a1dcb931d73103b3b61..1093085a242f7d75feb4c4636437149855ee383c 100644 (file)
--- a/src/include/access/twophase.h
+++ b/src/include/access/twophase.h
@@ -47,8 +47,6 @@ extern bool StandbyTransactionIdIsPrepared(TransactionId xid);
 
 extern TransactionId PrescanPreparedTransactions(TransactionId **xids_p,
                                                                                                 int *nxids_p);
-extern void ParsePrepareRecord(uint8 info, char *xlrec,
-                                                          xl_xact_parsed_prepare *parsed);
 extern void StandbyRecoverPreparedTransactions(void);
 extern void RecoverPreparedTransactions(void);
 

diff --git a/src/include/access/xact.h b/src/include/access/xact.h
index d7145517047c4be82534b79821888f51d0e4dcb0..42b76cb4dd3defb373275688e9921251b17dd49a 100644 (file)
--- a/src/include/access/xact.h
+++ b/src/include/access/xact.h
@@ -292,6 +292,24 @@ typedef struct xl_xact_abort
 } xl_xact_abort;
 #define MinSizeOfXactAbort sizeof(xl_xact_abort)
 
+typedef struct xl_xact_prepare
+{
+       uint32          magic;                  /* format identifier */
+       uint32          total_len;              /* actual file length */
+       TransactionId xid;                      /* original transaction XID */
+       Oid                     database;               /* OID of database it was in */
+       TimestampTz prepared_at;        /* time of preparation */
+       Oid                     owner;                  /* user running the transaction */
+       int32           nsubxacts;              /* number of following subxact XIDs */
+       int32           ncommitrels;    /* number of delete-on-commit rels */
+       int32           nabortrels;             /* number of delete-on-abort rels */
+       int32           ninvalmsgs;             /* number of cache invalidation messages */
+       bool            initfileinval;  /* does relcache init file need invalidation? */
+       uint16          gidlen;                 /* length of the GID - GID follows the header */
+       XLogRecPtr      origin_lsn;             /* lsn of this record at origin node */
+       TimestampTz origin_timestamp;   /* time of prepare at origin node */
+} xl_xact_prepare;
+
 /*
  * Commit/Abort records in the above form are a bit verbose to parse, so
  * there's a deconstructed versions generated by ParseCommit/AbortRecord() for
@@ -435,6 +453,7 @@ extern const char *xact_identify(uint8 info);
 /* also in xactdesc.c, so they can be shared between front/backend code */
 extern void ParseCommitRecord(uint8 info, xl_xact_commit *xlrec, xl_xact_parsed_commit *parsed);
 extern void ParseAbortRecord(uint8 info, xl_xact_abort *xlrec, xl_xact_parsed_abort *parsed);
+extern void ParsePrepareRecord(uint8 info, xl_xact_prepare *xlrec, xl_xact_parsed_prepare *parsed);
 
 extern void EnterParallelMode(void);
 extern void ExitParallelMode(void);