database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-24 14:22:24 +03:00
Code Activity

Avoid incrementing the CommandCounter when CommandCounterIncrement is called

Browse Source 
but no database changes have been made since the last CommandCounterIncrement.
This should result in a significant improvement in the number of "commands"
that can typically be performed within a transaction before hitting the 2^32
CommandId size limit.  In particular this buys back (and more) the possible
adverse consequences of my previous patch to fix plan caching behavior.

The implementation requires tracking whether the current CommandCounter
value has been "used" to mark any tuples.  CommandCounter values stored into
snapshots are presumed not to be used for this purpose.  This requires some
small executor changes, since the executor used to conflate the curcid of
the snapshot it was using with the command ID to mark output tuples with.
Separating these concepts allows some small simplifications in executor APIs.

Something for the TODO list: look into having CommandCounterIncrement not do
AcceptInvalidationMessages.  It seems fairly bogus to be doing it there,
but exactly where to do it instead isn't clear, and I'm disinclined to mess
with asynchronous behavior during late beta.
This commit is contained in:
Tom Lane
2007-11-30 21:22:54 +00:00
parent f0f18c7087
commit 895a94de6d
20 changed files with 217 additions and 252 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
src/backend/access/heap/heapam.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.245 2007/11/15 21:14:32 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.246 2007/11/30 21:22:53 tgl Exp $
*
*
* INTERFACE ROUTINES
@ -1891,7 +1891,7 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
Oid
simple_heap_insert(Relation relation, HeapTuple tup)
{
return heap_insert(relation, tup, GetCurrentCommandId(), true, true);
return heap_insert(relation, tup, GetCurrentCommandId(true), true, true);
}
/*
@ -2174,7 +2174,7 @@ simple_heap_delete(Relation relation, ItemPointer tid)
result = heap_delete(relation, tid,
&update_ctid, &update_xmax,
GetCurrentCommandId(), InvalidSnapshot,
GetCurrentCommandId(true), InvalidSnapshot,
true /* wait for commit */ );
switch (result)
{
@ -2817,7 +2817,7 @@ simple_heap_update(Relation relation, ItemPointer otid, HeapTuple tup)
result = heap_update(relation, otid, tup,
&update_ctid, &update_xmax,
GetCurrentCommandId(), InvalidSnapshot,
GetCurrentCommandId(true), InvalidSnapshot,
true /* wait for commit */ );
switch (result)
{

4
src/backend/access/heap/tuptoaster.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.79 2007/11/15 21:14:32 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.80 2007/11/30 21:22:53 tgl Exp $
*
*
* INTERFACE ROUTINES
@ -1086,7 +1086,7 @@ toast_save_datum(Relation rel, Datum value,
TupleDesc toasttupDesc;
Datum t_values[3];
bool t_isnull[3];
CommandId mycid = GetCurrentCommandId();
CommandId mycid = GetCurrentCommandId(true);
struct varlena *result;
struct varatt_external toast_pointer;
struct