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Emit invalidations to standby for transactions without xid.

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So far, when a transaction with pending invalidations, but without an
assigned xid, committed, we simply ignored those invalidation
messages. That's problematic, because those are actually sent for a
reason.

Known symptoms of this include that existing sessions on a hot-standby
replica sometimes fail to notice new concurrently built indexes and
visibility map updates.

The solution is to WAL log such invalidations in transactions without an
xid. We considered to alternatively force-assign an xid, but that'd be
problematic for vacuum, which might be run in systems with few xids.

Important: This adds a new WAL record, but as the patch has to be
back-patched, we can't bump the WAL page magic. This means that standbys
have to be updated before primaries; otherwise
"PANIC: standby_redo: unknown op code 32" errors can be encountered.

XXX:

Reported-By: Васильев Дмитрий, Masahiko Sawada
Discussion:
    CAB-SwXY6oH=9twBkXJtgR4UC1NqT-vpYAtxCseME62ADwyK5OA@mail.gmail.com
    CAD21AoDpZ6Xjg=gFrGPnSn4oTRRcwK1EBrWCq9OqOHuAcMMC=w@mail.gmail.com
This commit is contained in:
Andres Freund
2016-04-23 19:18:00 -07:00
parent 2ac3be2e76
commit c6ff84b06a
10 changed files with 181 additions and 48 deletions
Download Patch File Download Diff File Expand all files Collapse all files

53
src/backend/replication/logical/reorderbuffer.c
View File

@ -1810,26 +1810,8 @@ ReorderBufferForget(ReorderBuffer *rb, TransactionId xid, XLogRecPtr lsn)
* catalog and we need to update the caches according to that.
*/
if (txn->base_snapshot != NULL && txn->ninvalidations > 0)
{
bool use_subtxn = IsTransactionOrTransactionBlock();
if (use_subtxn)
BeginInternalSubTransaction("replay");
/*
* Force invalidations to happen outside of a valid transaction - that
* way entries will just be marked as invalid without accessing the
* catalog. That's advantageous because we don't need to setup the
* full state necessary for catalog access.
*/
if (use_subtxn)
AbortCurrentTransaction();
ReorderBufferExecuteInvalidations(rb, txn);
if (use_subtxn)
RollbackAndReleaseCurrentSubTransaction();
}
ReorderBufferImmediateInvalidation(rb, txn->ninvalidations,
txn->invalidations);
else
Assert(txn->ninvalidations == 0);
@ -1837,6 +1819,37 @@ ReorderBufferForget(ReorderBuffer *rb, TransactionId xid, XLogRecPtr lsn)
ReorderBufferCleanupTXN(rb, txn);
}
/*
* Execute invalidations happening outside the context of a decoded
* transaction. That currently happens either for xid-less commits
* (c.f. RecordTransactionCommit()) or for invalidations in uninteresting
* transactions (via ReorderBufferForget()).
*/
void
ReorderBufferImmediateInvalidation(ReorderBuffer *rb, uint32 ninvalidations,
SharedInvalidationMessage *invalidations)
{
bool use_subtxn = IsTransactionOrTransactionBlock();
int i;
if (use_subtxn)
BeginInternalSubTransaction("replay");
/*
* Force invalidations to happen outside of a valid transaction - that
* way entries will just be marked as invalid without accessing the
* catalog. That's advantageous because we don't need to setup the
* full state necessary for catalog access.
*/
if (use_subtxn)
AbortCurrentTransaction();
for (i = 0; i < ninvalidations; i++)
LocalExecuteInvalidationMessage(&invalidations[i]);
if (use_subtxn)
RollbackAndReleaseCurrentSubTransaction();
}
/*
* Tell reorderbuffer about an xid seen in the WAL stream. Has to be called at