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Allocate all page images at once in generic wal interface 

That reduces number of allocation.

Per gripe from Michael Paquier and Tom Lane suggestion.
This commit is contained in:
Teodor Sigaev 2016-05-17 22:09:22 +03:00
parent b09cd2e50a
commit 7c979c95a3
1 changed files with 9 additions and 10 deletions
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19
src/backend/access/transam/generic_xlog.c
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@ -61,8 +61,14 @@ typedef struct
/* State of generic xlog record construction */ /* State of generic xlog record construction */
struct GenericXLogState struct GenericXLogState
{ {
bool isLogged; /*
* page's images. Should be first in this struct to have MAXALIGN'ed
* images addresses, because some code working with pages directly aligns
* addresses, not an offsets from begining of page
*/
char images[MAX_GENERIC_XLOG_PAGES * BLCKSZ];
PageData pages[MAX_GENERIC_XLOG_PAGES]; PageData pages[MAX_GENERIC_XLOG_PAGES];
bool isLogged;
}; };
static void writeFragment(PageData *pageData, OffsetNumber offset, static void writeFragment(PageData *pageData, OffsetNumber offset,
@ -267,16 +273,11 @@ GenericXLogStart(Relation relation)
int i; int i;
state = (GenericXLogState *) palloc(sizeof(GenericXLogState)); state = (GenericXLogState *) palloc(sizeof(GenericXLogState));
state->isLogged = RelationNeedsWAL(relation); state->isLogged = RelationNeedsWAL(relation);
for (i = 0; i < MAX_GENERIC_XLOG_PAGES; i++) for (i = 0; i < MAX_GENERIC_XLOG_PAGES; i++)
{ {
/* state->pages[i].image = state->images + BLCKSZ * i;
* pre-alloc page's images to prevent allocation in
* GenericXLogRegisterBuffer() which could be called in different
* memory context(s)
*/
state->pages[i].image = palloc(BLCKSZ);
state->pages[i].buffer = InvalidBuffer; state->pages[i].buffer = InvalidBuffer;
} }
@ -432,8 +433,6 @@ GenericXLogFinish(GenericXLogState *state)
lsn = InvalidXLogRecPtr; lsn = InvalidXLogRecPtr;
} }
for (i = 0; i < MAX_GENERIC_XLOG_PAGES; i++)
pfree(state->pages[i].image);
pfree(state); pfree(state);
return lsn; return lsn;