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Allocate local buffers in a context of their own, rather than dumping them

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into TopMemoryContext.  This makes no functional difference, but makes it
easier to see what the space is being used for in MemoryContextStats dumps.
Per a recent example in which I was surprised by the size of TopMemoryContext.
This commit is contained in:
Tom Lane 2010-08-19 16:16:20 +00:00
parent e275d16a54
commit bc7cb8f42c
1 changed files with 16 additions and 3 deletions
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19
src/backend/storage/buffer/localbuf.c
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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/buffer/localbuf.c,v 1.90 2010/08/13 20:10:52 rhaas Exp $
* $PostgreSQL: pgsql/src/backend/storage/buffer/localbuf.c,v 1.91 2010/08/19 16:16:20 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -399,6 +399,7 @@ GetLocalBufferStorage(void)
static int next_buf_in_block = 0;
static int num_bufs_in_block = 0;
static int total_bufs_allocated = 0;
static MemoryContext LocalBufferContext = NULL;
char *this_buf;
@ -409,6 +410,19 @@ GetLocalBufferStorage(void)
/* Need to make a new request to memmgr */
int num_bufs;
/*
* We allocate local buffers in a context of their own, so that the
* space eaten for them is easily recognizable in MemoryContextStats
* output. Create the context on first use.
*/
if (LocalBufferContext == NULL)
LocalBufferContext =
AllocSetContextCreate(TopMemoryContext,
"LocalBufferContext",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/* Start with a 16-buffer request; subsequent ones double each time */
num_bufs = Max(num_bufs_in_block * 2, 16);
/* But not more than what we need for all remaining local bufs */
@ -416,8 +430,7 @@ GetLocalBufferStorage(void)
/* And don't overflow MaxAllocSize, either */
num_bufs = Min(num_bufs, MaxAllocSize / BLCKSZ);
/* Allocate space from TopMemoryContext so it never goes away */
cur_block = (char *) MemoryContextAlloc(TopMemoryContext,
cur_block = (char *) MemoryContextAlloc(LocalBufferContext,
num_bufs * BLCKSZ);
next_buf_in_block = 0;
num_bufs_in_block = num_bufs;