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Replace the BufMgrLock with separate locks on the lookup hashtable and

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the freelist, plus per-buffer spinlocks that protect access to individual
shared buffer headers.  This requires abandoning a global freelist (since
the freelist is a global contention point), which shoots down ARC and 2Q
as well as plain LRU management.  Adopt a clock sweep algorithm instead.
Preliminary results show substantial improvement in multi-backend situations.
This commit is contained in:
Tom Lane
2005-03-04 20:21:07 +00:00
parent 5592a6cf46
commit 5d5087363d
18 changed files with 1410 additions and 1932 deletions
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21
src/backend/postmaster/bgwriter.c
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@@ -37,7 +37,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.14 2005/02/19 23:16:15 tgl Exp $
* $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.15 2005/03/04 20:21:06 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -116,9 +116,6 @@ static BgWriterShmemStruct *BgWriterShmem;
* GUC parameters
*/
int BgWriterDelay = 200;
int BgWriterPercent = 1;
int BgWriterMaxPages = 100;
int CheckPointTimeout = 300;
int CheckPointWarning = 30;
@@ -274,7 +271,6 @@ BackgroundWriterMain(void)
bool force_checkpoint = false;
time_t now;
int elapsed_secs;
int n;
long udelay;
/*
@@ -365,16 +361,13 @@ BackgroundWriterMain(void)
* checkpoints happen at a predictable spacing.
*/
last_checkpoint_time = now;
/* Nap for configured time before rechecking */
n = 1;
}
else
n = BufferSync(BgWriterPercent, BgWriterMaxPages);
BgBufferSync();
/*
* Nap for the configured time or sleep for 10 seconds if there
* was nothing to do at all.
* Nap for the configured time, or sleep for 10 seconds if there
* is no bgwriter activity configured.
*
* On some platforms, signals won't interrupt the sleep. To ensure
* we respond reasonably promptly when someone signals us, break
@@ -383,7 +376,11 @@ BackgroundWriterMain(void)
*
* We absorb pending requests after each short sleep.
*/
udelay = ((n > 0) ? BgWriterDelay : 10000) * 1000L;
if ((bgwriter_all_percent > 0.0 && bgwriter_all_maxpages > 0) ||
(bgwriter_lru_percent > 0.0 && bgwriter_lru_maxpages > 0))
udelay = BgWriterDelay * 1000L;
else
udelay = 10000000L;
while (udelay > 1000000L)
{
if (got_SIGHUP || checkpoint_requested || shutdown_requested)