From 7cb2ff9621a6129cc251f9d06bf23d3f9d426173 Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Tue, 21 Jun 2011 14:12:40 +0300 Subject: [PATCH] Fix bug introduced by recent SSI patch to merge ROLLED_BACK and MARKED_FOR_DEATH flags into one. We still need the ROLLED_BACK flag to mark transactions that are in the process of being rolled back. To be precise, ROLLED_BACK now means that a transaction has already been discounted from the count of transactions with the oldest xmin, but not yet removed from the list of active transactions. Dan Ports --- src/backend/storage/lmgr/predicate.c | 21 +++++++++++++++++++-- src/include/storage/predicate_internals.h | 21 +++++++++++---------- 2 files changed, 30 insertions(+), 12 deletions(-) diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c index 3678878f03..8cbca78fb7 100644 --- a/src/backend/storage/lmgr/predicate.c +++ b/src/backend/storage/lmgr/predicate.c @@ -246,6 +246,7 @@ #define SxactIsCommitted(sxact) (((sxact)->flags & SXACT_FLAG_COMMITTED) != 0) #define SxactIsPrepared(sxact) (((sxact)->flags & SXACT_FLAG_PREPARED) != 0) +#define SxactIsRolledBack(sxact) (((sxact)->flags & SXACT_FLAG_ROLLED_BACK) != 0) #define SxactIsDoomed(sxact) (((sxact)->flags & SXACT_FLAG_DOOMED) != 0) #define SxactIsReadOnly(sxact) (((sxact)->flags & SXACT_FLAG_READ_ONLY) != 0) #define SxactHasSummaryConflictIn(sxact) (((sxact)->flags & SXACT_FLAG_SUMMARY_CONFLICT_IN) != 0) @@ -3046,7 +3047,7 @@ SetNewSxactGlobalXmin(void) for (sxact = FirstPredXact(); sxact != NULL; sxact = NextPredXact(sxact)) { - if (!SxactIsDoomed(sxact) + if (!SxactIsRolledBack(sxact) && !SxactIsCommitted(sxact) && sxact != OldCommittedSxact) { @@ -3113,6 +3114,7 @@ ReleasePredicateLocks(const bool isCommit) Assert(!isCommit || SxactIsPrepared(MySerializableXact)); Assert(!isCommit || !SxactIsDoomed(MySerializableXact)); Assert(!SxactIsCommitted(MySerializableXact)); + Assert(!SxactIsRolledBack(MySerializableXact)); /* may not be serializable during COMMIT/ROLLBACK PREPARED */ if (MySerializableXact->pid != 0) @@ -3151,7 +3153,22 @@ ReleasePredicateLocks(const bool isCommit) MySerializableXact->flags |= SXACT_FLAG_READ_ONLY; } else + { + /* + * The DOOMED flag indicates that we intend to roll back this + * transaction and so it should not cause serialization failures for + * other transactions that conflict with it. Note that this flag might + * already be set, if another backend marked this transaction for + * abort. + * + * The ROLLED_BACK flag further indicates that ReleasePredicateLocks + * has been called, and so the SerializableXact is eligible for + * cleanup. This means it should not be considered when calculating + * SxactGlobalXmin. + */ MySerializableXact->flags |= SXACT_FLAG_DOOMED; + MySerializableXact->flags |= SXACT_FLAG_ROLLED_BACK; + } if (!topLevelIsDeclaredReadOnly) { @@ -3527,7 +3544,7 @@ ReleaseOneSerializableXact(SERIALIZABLEXACT *sxact, bool partial, nextConflict; Assert(sxact != NULL); - Assert(SxactIsDoomed(sxact) || SxactIsCommitted(sxact)); + Assert(SxactIsRolledBack(sxact) || SxactIsCommitted(sxact)); Assert(LWLockHeldByMe(SerializableFinishedListLock)); /* diff --git a/src/include/storage/predicate_internals.h b/src/include/storage/predicate_internals.h index 495983f345..0c90f275d6 100644 --- a/src/include/storage/predicate_internals.h +++ b/src/include/storage/predicate_internals.h @@ -90,21 +90,22 @@ typedef struct SERIALIZABLEXACT int pid; /* pid of associated process */ } SERIALIZABLEXACT; -#define SXACT_FLAG_COMMITTED 0x00000001 /* already committed */ -#define SXACT_FLAG_PREPARED 0x00000002 /* about to commit */ -#define SXACT_FLAG_DOOMED 0x00000004 /* will roll back */ +#define SXACT_FLAG_COMMITTED 0x00000001 /* already committed */ +#define SXACT_FLAG_PREPARED 0x00000002 /* about to commit */ +#define SXACT_FLAG_ROLLED_BACK 0x00000004 /* already rolled back */ +#define SXACT_FLAG_DOOMED 0x00000008 /* will roll back */ /* * The following flag actually means that the flagged transaction has a * conflict out *to a transaction which committed ahead of it*. It's hard * to get that into a name of a reasonable length. */ -#define SXACT_FLAG_CONFLICT_OUT 0x00000008 -#define SXACT_FLAG_READ_ONLY 0x00000010 -#define SXACT_FLAG_DEFERRABLE_WAITING 0x00000020 -#define SXACT_FLAG_RO_SAFE 0x00000040 -#define SXACT_FLAG_RO_UNSAFE 0x00000080 -#define SXACT_FLAG_SUMMARY_CONFLICT_IN 0x00000100 -#define SXACT_FLAG_SUMMARY_CONFLICT_OUT 0x00000200 +#define SXACT_FLAG_CONFLICT_OUT 0x00000010 +#define SXACT_FLAG_READ_ONLY 0x00000020 +#define SXACT_FLAG_DEFERRABLE_WAITING 0x00000040 +#define SXACT_FLAG_RO_SAFE 0x00000080 +#define SXACT_FLAG_RO_UNSAFE 0x00000100 +#define SXACT_FLAG_SUMMARY_CONFLICT_IN 0x00000200 +#define SXACT_FLAG_SUMMARY_CONFLICT_OUT 0x00000400 /* * The following types are used to provide an ad hoc list for holding