On Thu, 2009-06-25 at 17:35 +0300, Heikki Linnakangas wrote:
> Heikki Linnakangas wrote:
> > Hmm, what happens when the startup process performs a write, and
> > bgwriter is not running? Do the fsync requests queue up in the shmem
> > queue until the end of recovery when bgwriter is launched? I guess I'll
> > have to try it out...
>
> Oh dear, doesn't look good. The startup process has a pendingOpsTable of
> its own. bgwriter won't fsync() files that the startup process has
> written itself. That needs to be fixed, or you can lose data when an
> archive recovery crashes after a restartpoint.
Yes, that's what I see also. Patch attached.
--
Simon Riggs www.2ndQuadrant.com
PostgreSQL Training, Services and Support
Index: src/backend/access/transam/xlog.c
===================================================================
RCS file: /home/sriggs/pg/REPOSITORY/pgsql/src/backend/access/transam/xlog.c,v
retrieving revision 1.343
diff -c -r1.343 xlog.c
*** src/backend/access/transam/xlog.c 11 Jun 2009 14:48:54 -0000 1.343
--- src/backend/access/transam/xlog.c 25 Jun 2009 15:00:13 -0000
***************
*** 5472,5479 ****
* process in addition to postmaster!
*/
if (InArchiveRecovery && IsUnderPostmaster)
SendPostmasterSignal(PMSIGNAL_RECOVERY_STARTED);
!
/*
* main redo apply loop
*/
--- 5472,5482 ----
* process in addition to postmaster!
*/
if (InArchiveRecovery && IsUnderPostmaster)
+ {
SendPostmasterSignal(PMSIGNAL_RECOVERY_STARTED);
! SetForwardFsyncRequests();
! }
!
/*
* main redo apply loop
*/
Index: src/backend/storage/smgr/md.c
===================================================================
RCS file: /home/sriggs/pg/REPOSITORY/pgsql/src/backend/storage/smgr/md.c,v
retrieving revision 1.146
diff -c -r1.146 md.c
*** src/backend/storage/smgr/md.c 11 Jun 2009 14:49:02 -0000 1.146
--- src/backend/storage/smgr/md.c 25 Jun 2009 15:02:26 -0000
***************
*** 141,146 ****
--- 141,147 ----
static HTAB *pendingOpsTable = NULL;
static List *pendingUnlinks = NIL;
+ static remember_fsync_requests_locally = false;
static CycleCtr mdsync_cycle_ctr = 0;
static CycleCtr mdckpt_cycle_ctr = 0;
***************
*** 199,204 ****
--- 200,206 ----
100L,
&hash_ctl,
HASH_ELEM | HASH_FUNCTION | HASH_CONTEXT);
+ remember_fsync_requests_locally = true;
pendingUnlinks = NIL;
}
}
***************
*** 1180,1185 ****
--- 1182,1202 ----
}
/*
+ * InArchiveRecovery we need forward requests to the bgwriter.
+ */
+ void
+ SetForwardFsyncRequests(void)
+ {
+ remember_fsync_requests_locally = false;
+
+ /*
+ * In case caller has any pending ops
+ */
+ if (pendingOpsTable)
+ mdsync();
+ }
+
+ /*
* register_dirty_segment() -- Mark a relation segment as needing fsync
*
* If there is a local pending-ops table, just make an entry in it for
***************
*** 1191,1197 ****
static void
register_dirty_segment(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
{
! if (pendingOpsTable)
{
/* push it into local pending-ops table */
RememberFsyncRequest(reln->smgr_rnode, forknum, seg->mdfd_segno);
--- 1208,1214 ----
static void
register_dirty_segment(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
{
! if (remember_fsync_requests_locally)
{
/* push it into local pending-ops table */
RememberFsyncRequest(reln->smgr_rnode, forknum, seg->mdfd_segno);
***************
*** 1219,1225 ****
static void
register_unlink(RelFileNode rnode)
{
! if (pendingOpsTable)
{
/* push it into local pending-ops table */
RememberFsyncRequest(rnode, MAIN_FORKNUM, UNLINK_RELATION_REQUEST);
--- 1236,1242 ----
static void
register_unlink(RelFileNode rnode)
{
! if (remember_fsync_requests_locally)
{
/* push it into local pending-ops table */
RememberFsyncRequest(rnode, MAIN_FORKNUM, UNLINK_RELATION_REQUEST);
***************
*** 1377,1383 ****
void
ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum)
{
! if (pendingOpsTable)
{
/* standalone backend or startup process: fsync state is local */
RememberFsyncRequest(rnode, forknum, FORGET_RELATION_FSYNC);
--- 1394,1400 ----
void
ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum)
{
! if (remember_fsync_requests_locally)
{
/* standalone backend or startup process: fsync state is local */
RememberFsyncRequest(rnode, forknum, FORGET_RELATION_FSYNC);
***************
*** 1416,1422 ****
rnode.spcNode = 0;
rnode.relNode = 0;
! if (pendingOpsTable)
{
/* standalone backend or startup process: fsync state is local */
RememberFsyncRequest(rnode, InvalidForkNumber, FORGET_DATABASE_FSYNC);
--- 1433,1439 ----
rnode.spcNode = 0;
rnode.relNode = 0;
! if (remember_fsync_requests_locally)
{
/* standalone backend or startup process: fsync state is local */
RememberFsyncRequest(rnode, InvalidForkNumber, FORGET_DATABASE_FSYNC);
Index: src/include/storage/smgr.h
===================================================================
RCS file: /home/sriggs/pg/REPOSITORY/pgsql/src/include/storage/smgr.h,v
retrieving revision 1.67
diff -c -r1.67 smgr.h
*** src/include/storage/smgr.h 11 Jun 2009 14:49:12 -0000 1.67
--- src/include/storage/smgr.h 25 Jun 2009 14:59:43 -0000
***************
*** 109,114 ****
--- 109,115 ----
extern void mdsync(void);
extern void mdpostckpt(void);
+ extern void SetForwardFsyncRequests(void);
extern void RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum,
BlockNumber segno);
extern void ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum);
--
Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-bugs
