mirrors/postgres
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Tweak BgBufferSync() so that a persistent write error on a dirty buffer

Browse Source 
doesn't block the bgwriter from making progress writing out other buffers.
This was a hard problem in the context of the ARC/2Q design, but it's
trivial in the context of clock sweep ... just advance the sweep counter
before we try to write not after.
This commit is contained in:
Tom Lane 2005-08-02 20:52:08 +00:00
parent 688784f671
commit 6eac4e69cf
2 changed files with 17 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
src/backend/postmaster/bgwriter.c
View File

@ -37,7 +37,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.17 2005/06/30 00:00:51 tgl Exp $
* $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.18 2005/08/02 20:52:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -256,8 +256,7 @@ BackgroundWriterMain(void)
/*
* Sleep at least 1 second after any error. A write error is
* likely to be repeated, and we don't want to be filling the
* error logs as fast as we can. (XXX think about ways to make
* progress when the LRU dirty buffer cannot be written...)
* error logs as fast as we can.
*/
pg_usleep(1000000L);
}

23
src/backend/storage/buffer/bufmgr.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.189 2005/05/19 21:35:46 tgl Exp $
* $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.190 2005/08/02 20:52:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -903,6 +903,11 @@ BgBufferSync(void)
/*
* This loop runs over all buffers, including pinned ones. The
* starting point advances through the buffer pool on successive calls.
*
* Note that we advance the static counter *before* trying to write.
* This ensures that, if we have a persistent write failure on a dirty
* buffer, we'll still be able to make progress writing other buffers.
* (The bgwriter will catch the error and just call us again later.)
*/
if (bgwriter_all_percent > 0.0 && bgwriter_all_maxpages > 0)
{
@ -911,12 +916,13 @@ BgBufferSync(void)
while (num_to_scan-- > 0)
{
if (SyncOneBuffer(buf_id1, false))
num_written++;
if (++buf_id1 >= NBuffers)
buf_id1 = 0;
if (num_written >= bgwriter_all_maxpages)
break;
if (SyncOneBuffer(buf_id1, false))
{
if (++num_written >= bgwriter_all_maxpages)
break;
}
}
}
@ -934,11 +940,12 @@ BgBufferSync(void)
while (num_to_scan-- > 0)
{
if (SyncOneBuffer(buf_id2, true))
num_written++;
{
if (++num_written >= bgwriter_lru_maxpages)
break;
}
if (++buf_id2 >= NBuffers)
buf_id2 = 0;
if (num_written >= bgwriter_lru_maxpages)
break;
}
}
}