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Revert addition of pg_terminate_backend() because of race conditions.

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This commit is contained in:
Bruce Momjian
2008-04-15 20:28:47 +00:00
parent 2b8a795738
commit 76365960d2
9 changed files with 43 additions and 92 deletions
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63
src/backend/utils/adt/misc.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/misc.c,v 1.60 2008/04/15 13:55:11 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/misc.c,v 1.61 2008/04/15 20:28:46 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -27,7 +27,6 @@
#include "postmaster/syslogger.h"
#include "storage/fd.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "utils/builtins.h"
#include "tcop/tcopprot.h"
@ -90,7 +89,7 @@ current_query(PG_FUNCTION_ARGS)
* Functions to send signals to other backends.
*/
static bool
pg_signal_check(int pid)
pg_signal_backend(int pid, int sig)
{
if (!superuser())
ereport(ERROR,
@ -107,16 +106,7 @@ pg_signal_check(int pid)
(errmsg("PID %d is not a PostgreSQL server process", pid)));
return false;
}
else
return true;
}
/*
* Functions to send signals to other backends.
*/
static bool
pg_signal_backend(int pid, int sig)
{
/* If we have setsid(), signal the backend's whole process group */
#ifdef HAVE_SETSID
if (kill(-pid, sig))
@ -135,43 +125,7 @@ pg_signal_backend(int pid, int sig)
Datum
pg_cancel_backend(PG_FUNCTION_ARGS)
{
int pid = PG_GETARG_INT32(0);
if (pg_signal_check(pid))
PG_RETURN_BOOL(pg_signal_backend(pid, SIGINT));
else
PG_RETURN_BOOL(false);
}
/*
* To cleanly terminate a backend, we set PGPROC(pid)->terminate
* then send a cancel signal. We get ProcArrayLock only when
* setting PGPROC->terminate so the function might fail in
* several places, but that is fine because in those cases the
* backend is already gone.
*/
Datum
pg_terminate_backend(PG_FUNCTION_ARGS)
{
int pid = PG_GETARG_INT32(0);
volatile PGPROC *term_proc;
/* Is this the super-user, and can we find the PGPROC entry for the pid? */
if (pg_signal_check(pid) && (term_proc = BackendPidGetProc(pid)) != NULL)
{
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
/* Recheck now that we have the ProcArray lock. */
if (term_proc->pid == pid)
{
term_proc->terminate = true;
LWLockRelease(ProcArrayLock);
PG_RETURN_BOOL(pg_signal_backend(pid, SIGINT));
}
else
LWLockRelease(ProcArrayLock);
}
PG_RETURN_BOOL(false);
PG_RETURN_BOOL(pg_signal_backend(PG_GETARG_INT32(0), SIGINT));
}
Datum
@ -215,6 +169,17 @@ pg_rotate_logfile(PG_FUNCTION_ARGS)
PG_RETURN_BOOL(true);
}
#ifdef NOT_USED
/* Disabled in 8.0 due to reliability concerns; FIXME someday */
Datum
pg_terminate_backend(PG_FUNCTION_ARGS)
{
PG_RETURN_INT32(pg_signal_backend(PG_GETARG_INT32(0), SIGTERM));
}
#endif
/* Function to find out which databases make use of a tablespace */
typedef struct