Re: WAL recycling, Linux 2.4.18

> > I was able to set a breakpoint at CreateCheckPoint - gdb never found a
> > MoveOfflineLogs for me to set a breakpoint.
>
>Grumble.  It's a static routine, and I imagine its name has been totally
>stripped from the executable.

I can now set the breakpoint there with the unstripped executable.

It seems that the MoveOfflineLogs takes very little time; "fin" returns
almost immediately from it.

However, between the breakpoint at CreateCheckPoint and the one at
MoveOfflineLogs takes quite a bit of time.

See transcript: (starting from the completion of a previous "checkpoint"
command and just about to issue another) My notes are embedded with *** NOTE

gdb) where
#0  CreateCheckPoint (shutdown=0 '\0') at xlog.c:3125
#1  0x08111066 in ProcessUtility (parsetree=0x837b468, dest=Remote,
     completionTag=0xbfffdf10 "") at utility.c:778
#2  0x0810ecc5 in pg_exec_query_string (query_string=0x837b2d8 "CHECKPOINT;",
     dest=Remote, parse_context=0x834e628) at postgres.c:766
#3  0x0810fd5e in PostgresMain (argc=4, argv=0xbfffe140,
     username=0x8329e29 "dfields") at postgres.c:1926
#4  0x080f6d4e in DoBackend (port=0x8329cf8) at postmaster.c:2243
#5  0x080f669f in BackendStartup (port=0x8329cf8) at postmaster.c:1874
#6  0x080f5882 in ServerLoop () at postmaster.c:995
#7  0x080f5391 in PostmasterMain (argc=1, argv=0x8312448) at postmaster.c:771
#8  0x080d4e18 in main (argc=1, argv=0xbfffeac4) at main.c:206
(gdb) c
Continuing.

Breakpoint 1, CreateCheckPoint (shutdown=0 '\0') at xlog.c:2912
2912    in xlog.c
(gdb) c
Continuing.
*** NOTE: it now takes a bit of time to get to this next breakpoint

Breakpoint 2, MoveOfflineLogs (log=14, seg=88, endptr=
       {xlogid = 14, xrecoff = 1556353340}) at xlog.c:1604
1604    in xlog.c
(gdb) fin
Run till exit from #0  MoveOfflineLogs (log=14, seg=88, endptr=
       {xlogid = 14, xrecoff = 1556353340}) at xlog.c:1604
*** NOTE: This "fin" command returns almost immediately
CreateCheckPoint (shutdown=0 '\0') at xlog.c:3125
3125    in xlog.c
(gdb) c
Continuing.