database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-27 12:41:57 +03:00
Code Activity

Make smart shutdown work in combination with Hot Standby/Streaming Replication.

Browse Source 
At present, killing the startup process does not release any locks it holds,
so we must wait to stop the startup and walreceiver processes until all
read-only backends have exited.  Without this patch, the startup and
walreceiver processes never exit, so the server gets permanently stuck in
a half-shutdown state.

Fujii Masao, with review, docs, and comment adjustments by me.
This commit is contained in:
Robert Haas
2010-04-08 01:39:37 +00:00
parent 2c0870ff7a
commit 1c850fa807
3 changed files with 42 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
src/backend/postmaster/postmaster.c
View File

@ -37,7 +37,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.604 2010/03/25 20:40:17 sriggs Exp $
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.605 2010/04/08 01:39:37 rhaas Exp $
*
* NOTES
*
@ -278,6 +278,7 @@ typedef enum
PM_RECOVERY_CONSISTENT, /* consistent recovery mode */
PM_RUN, /* normal "database is alive" state */
PM_WAIT_BACKUP, /* waiting for online backup mode to end */
PM_WAIT_READONLY, /* waiting for read only backends to exit */
PM_WAIT_BACKENDS, /* waiting for live backends to exit */
PM_SHUTDOWN, /* waiting for bgwriter to do shutdown ckpt */
PM_SHUTDOWN_2, /* waiting for archiver and walsenders to
@ -2173,7 +2174,17 @@ pmdie(SIGNAL_ARGS)
/* and the walwriter too */
if (WalWriterPID != 0)
signal_child(WalWriterPID, SIGTERM);
pmState = PM_WAIT_BACKUP;
/*
* If we're in recovery, we can't kill the startup process
* right away, because at present doing so does not release
* its locks. We might want to change this in a future
* release. For the time being, the PM_WAIT_READONLY state
* indicates that we're waiting for the regular (read only)
* backends to die off; once they do, we'll kill the startup
* and walreceiver processes.
*/
pmState = (pmState == PM_RUN) ?
PM_WAIT_BACKUP : PM_WAIT_READONLY;
}
/*
@ -2209,6 +2220,7 @@ pmdie(SIGNAL_ARGS)
}
if (pmState == PM_RUN ||
pmState == PM_WAIT_BACKUP ||
pmState == PM_WAIT_READONLY ||
pmState == PM_WAIT_BACKENDS ||
pmState == PM_RECOVERY_CONSISTENT)
{
@ -2771,6 +2783,7 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
pmState == PM_RECOVERY_CONSISTENT ||
pmState == PM_RUN ||
pmState == PM_WAIT_BACKUP ||
pmState == PM_WAIT_READONLY ||
pmState == PM_SHUTDOWN)
pmState = PM_WAIT_BACKENDS;
}
@ -2846,6 +2859,26 @@ PostmasterStateMachine(void)
pmState = PM_WAIT_BACKENDS;
}
if (pmState == PM_WAIT_READONLY)
{
/*
* PM_WAIT_READONLY state ends when we have no regular backends that
* have been started during recovery. We kill the startup and
* walreceiver processes and transition to PM_WAIT_BACKENDS. Ideally,
* we might like to kill these processes first and then wait for
* backends to die off, but that doesn't work at present because
* killing the startup process doesn't release its locks.
*/
if (CountChildren(BACKEND_TYPE_NORMAL) == 0)
{
if (StartupPID != 0)
signal_child(StartupPID, SIGTERM);
if (WalReceiverPID != 0)
signal_child(WalReceiverPID, SIGTERM);
pmState = PM_WAIT_BACKENDS;
}
}
/*
* If we are in a state-machine state that implies waiting for backends to
* exit, see if they're all gone, and change state if so.