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Separate out bgwriter code into a logically separate module, rather

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than being random pieces of other files.  Give bgwriter responsibility
for all checkpoint activity (other than a post-recovery checkpoint);
so this child process absorbs the functionality of the former transient
checkpoint and shutdown subprocesses.  While at it, create an actual
include file for postmaster.c, which for some reason never had its own
file before.
This commit is contained in:
Tom Lane
2004-05-29 22:48:23 +00:00
parent d531fd2cdc
commit 076a055acf
28 changed files with 1133 additions and 902 deletions
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72
src/backend/storage/buffer/bufmgr.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.165 2004/05/08 19:09:25 tgl Exp $
* $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.166 2004/05/29 22:48:19 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -60,10 +60,6 @@ bool zero_damaged_pages = false;
bool ShowPinTrace = false;
#endif
int BgWriterDelay = 200;
int BgWriterPercent = 1;
int BgWriterMaxpages = 100;
long NDirectFileRead; /* some I/O's are direct file access.
* bypass bufmgr */
long NDirectFileWrite; /* e.g., I/O in psort and hashjoin. */
@ -862,72 +858,6 @@ FlushBufferPool(void)
}
/*
* BufferBackgroundWriter
*
* Periodically flushes dirty blocks from the buffer pool to keep
* the LRU list clean, preventing regular backends from writing.
*/
void
BufferBackgroundWriter(void)
{
if (BgWriterPercent == 0)
return;
/*
* Loop forever
*/
for (;;)
{
int n;
long udelay;
/*
* Call BufferSync() with instructions to keep just the
* LRU heads clean.
*/
n = BufferSync(BgWriterPercent, BgWriterMaxpages);
/*
* Whatever signal is sent to us, let's just die gallantly. If
* it wasn't meant that way, the postmaster will reincarnate us.
*/
if (InterruptPending)
return;
/*
* Whenever we have nothing to do, close all smgr files. This
* is so we won't hang onto smgr references to deleted files
* indefinitely. XXX this is a bogus, temporary solution. 'Twould
* be much better to do this once per checkpoint, but the bgwriter
* doesn't yet know anything about checkpoints.
*/
if (n == 0)
smgrcloseall();
/*
* Nap for the configured time or sleep for 10 seconds if
* there was nothing to do at all.
*
* On some platforms, signals won't interrupt the sleep. To ensure
* we respond reasonably promptly when the postmaster signals us,
* break down the sleep into 1-second increments, and check for
* interrupts after each nap.
*/
udelay = ((n > 0) ? BgWriterDelay : 10000) * 1000L;
while (udelay > 1000000L)
{
pg_usleep(1000000L);
udelay -= 1000000L;
if (InterruptPending)
return;
}
pg_usleep(udelay);
if (InterruptPending)
return;
}
}
/*
* Do whatever is needed to prepare for commit at the bufmgr and smgr levels
*/