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Allow Hot Standby to begin from a shutdown checkpoint.

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Patch by Simon Riggs & me
This commit is contained in:
Heikki Linnakangas
2010-04-13 14:17:46 +00:00
parent ea9c103237
commit 361bd1662e
3 changed files with 224 additions and 62 deletions
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85
src/backend/access/transam/twophase.c
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@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/transam/twophase.c,v 1.59 2010/02/26 02:00:34 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/transam/twophase.c,v 1.60 2010/04/13 14:17:46 heikki Exp $
*
* NOTES
* Each global transaction is associated with a global transaction
@@ -1718,6 +1718,89 @@ PrescanPreparedTransactions(TransactionId **xids_p, int *nxids_p)
return result;
}
/*
* StandbyRecoverPreparedTransactions
*
* Scan the pg_twophase directory and setup all the required information to
* allow standby queries to treat prepared transactions as still active.
* This is never called at the end of recovery - we use
* RecoverPreparedTransactions() at that point.
*
* Currently we simply call SubTransSetParent() for any subxids of prepared
* transactions. If overwriteOK is true, it's OK if some XIDs have already
* been marked in pg_subtrans.
*/
void
StandbyRecoverPreparedTransactions(bool overwriteOK)
{
DIR *cldir;
struct dirent *clde;
cldir = AllocateDir(TWOPHASE_DIR);
while ((clde = ReadDir(cldir, TWOPHASE_DIR)) != NULL)
{
if (strlen(clde->d_name) == 8 &&
strspn(clde->d_name, "0123456789ABCDEF") == 8)
{
TransactionId xid;
char *buf;
TwoPhaseFileHeader *hdr;
TransactionId *subxids;
int i;
xid = (TransactionId) strtoul(clde->d_name, NULL, 16);
/* Already processed? */
if (TransactionIdDidCommit(xid) || TransactionIdDidAbort(xid))
{
ereport(WARNING,
(errmsg("removing stale two-phase state file \"%s\"",
clde->d_name)));
RemoveTwoPhaseFile(xid, true);
continue;
}
/* Read and validate file */
buf = ReadTwoPhaseFile(xid, true);
if (buf == NULL)
{
ereport(WARNING,
(errmsg("removing corrupt two-phase state file \"%s\"",
clde->d_name)));
RemoveTwoPhaseFile(xid, true);
continue;
}
/* Deconstruct header */
hdr = (TwoPhaseFileHeader *) buf;
if (!TransactionIdEquals(hdr->xid, xid))
{
ereport(WARNING,
(errmsg("removing corrupt two-phase state file \"%s\"",
clde->d_name)));
RemoveTwoPhaseFile(xid, true);
pfree(buf);
continue;
}
/*
* Examine subtransaction XIDs ... they should all follow main
* XID.
*/
subxids = (TransactionId *)
(buf + MAXALIGN(sizeof(TwoPhaseFileHeader)));
for (i = 0; i < hdr->nsubxacts; i++)
{
TransactionId subxid = subxids[i];
Assert(TransactionIdFollows(subxid, xid));
SubTransSetParent(xid, subxid, overwriteOK);
}
}
}
FreeDir(cldir);
}
/*
* RecoverPreparedTransactions
*