Re: Relation cache invalidation on replica
| От | Simon Riggs |
|---|---|
| Тема | Re: Relation cache invalidation on replica |
| Дата | |
| Msg-id | CANP8+jLBdAopmx-GRkmooa1=pNM3Nh=ymCEFRWjZTiKxLeJJmg@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Relation cache invalidation on replica (Andres Freund <andres@anarazel.de>) |
| Ответы |
Re: Relation cache invalidation on replica
|
| Список | pgsql-hackers |
On 27 February 2016 at 01:23, Andres Freund <andres@anarazel.de> wrote:
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index f443742..94282a0 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -6022,6 +6022,7 @@ heap_abort_speculative(Relation relation, HeapTuple tuple)
void
heap_inplace_update(Relation relation, HeapTuple tuple)
{
+ TransactionId xid = GetCurrentTransactionId();
Buffer buffer;
Page page;
OffsetNumber offnum;
--
On 2016-02-27 01:16:34 +0000, Simon Riggs wrote:
> If the above is true, then the proposed fix wouldn't work either.
>
> No point in sending a cache invalidation message on the standby if you
> haven't also written WAL, since the catalog re-read would just see the old
> row.
>
> heap_inplace_update() does write WAL, which blows away the starting premise.
I'm not following here. heap_inplace_update() indeed writes WAL, but it
does *NOT* (and may not) assign an xid. Thus we're not emitting the
relcache invalidation queued in DefineIndex(), as
RecordTransactionCommit() currently skips emitting a commit record if
there's no xid.
OK.
Surely then the fix is to make heap_inplace_update() assign an xid? That way any catalog change will always generate a commit record containing the invalidation that goes with the change. No need to fix up the breakage later.
The other heap_insert|update|delete functions (and similar) all assign xid, so it is consistent for us to do that for inplace_update also.
index f443742..94282a0 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -6022,6 +6022,7 @@ heap_abort_speculative(Relation relation, HeapTuple tuple)
void
heap_inplace_update(Relation relation, HeapTuple tuple)
{
+ TransactionId xid = GetCurrentTransactionId();
Buffer buffer;
Page page;
OffsetNumber offnum;
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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