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New autovacuum_work_mem parameter

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If autovacuum_work_mem is set, autovacuum workers now use
this parameter in preference to maintenance_work_mem.

Peter Geoghegan
This commit is contained in:
Simon Riggs
2013-12-12 11:42:39 +00:00
parent 36da3cfb45
commit 8693559cac
6 changed files with 69 additions and 10 deletions
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19
src/backend/commands/vacuumlazy.c
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@@ -10,13 +10,13 @@
* relations with finite memory space usage. To do that, we set upper bounds
* on the number of tuples and pages we will keep track of at once.
*
* We are willing to use at most maintenance_work_mem memory space to keep
* track of dead tuples. We initially allocate an array of TIDs of that size,
* with an upper limit that depends on table size (this limit ensures we don't
* allocate a huge area uselessly for vacuuming small tables). If the array
* threatens to overflow, we suspend the heap scan phase and perform a pass of
* index cleanup and page compaction, then resume the heap scan with an empty
* TID array.
* We are willing to use at most maintenance_work_mem (or perhaps
* autovacuum_work_mem) memory space to keep track of dead tuples. We
* initially allocate an array of TIDs of that size, with an upper limit that
* depends on table size (this limit ensures we don't allocate a huge area
* uselessly for vacuuming small tables). If the array threatens to overflow,
* we suspend the heap scan phase and perform a pass of index cleanup and page
* compaction, then resume the heap scan with an empty TID array.
*
* If we're processing a table with no indexes, we can just vacuum each page
* as we go; there's no need to save up multiple tuples to minimize the number
@@ -1599,10 +1599,13 @@ static void
lazy_space_alloc(LVRelStats *vacrelstats, BlockNumber relblocks)
{
long maxtuples;
int vac_work_mem = IsAutoVacuumWorkerProcess() &&
autovacuum_work_mem != -1 ?
autovacuum_work_mem : maintenance_work_mem;
if (vacrelstats->hasindex)
{
maxtuples = (maintenance_work_mem * 1024L) / sizeof(ItemPointerData);
maxtuples = (vac_work_mem * 1024L) / sizeof(ItemPointerData);
maxtuples = Min(maxtuples, INT_MAX);
maxtuples = Min(maxtuples, MaxAllocSize / sizeof(ItemPointerData));