Hi, On 27/01/14 11:44, Rajeev rastogi wrote: > I have checked the revised patch. It looks fine to me except one minor code > formatting issue. > In elog.c, two tabs are missing in the definition of function > "errdetail_log_plural". > Please run pgindent tool to check the same.
I did, but this reformats various other locations in the file, too. Nevertheless I now ran pg_indent against it and removed the other parts. Attached you will find the corrected patch version. > Also I would like to highlight one behavior here is that process ID of > process trying to > acquire lock is also listed in the list of "Request queue". E.g. > > session 1 with process id X: BEGIN; LOCK TABLE foo IN SHARE MODE; > session 2 with process id Y: BEGIN; LOCK TABLE foo IN EXCLUSIVE MODE; > > On execution of LOCK in session-2, as part of log it will display as: > DETAIL: Process holding the lock: X. Request queue: Y. > > Where Y is the process ID of same process, which was trying to acquire > lock. This is on purpose due to the rewording of the Message. In the first version the PID of the backend was missing. Thanks for the review! Best regards, -- Christian Kruse http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index ee6c24c..6c648cf 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1195,13 +1195,23 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
*/
if (log_lock_waits && deadlock_state != DS_NOT_YET_CHECKED)
{
- StringInfoData buf;
+ StringInfoData buf,
+ lock_waiters_sbuf,
+ lock_holders_sbuf;
const char *modename;
long secs;
int usecs;
long msecs;
+ SHM_QUEUE *procLocks;
+ PROCLOCK *proclock;
+ bool first_holder = true,
+ first_waiter = true;
+ int lockHoldersNum = 0;
initStringInfo(&buf);
+ initStringInfo(&lock_waiters_sbuf);
+ initStringInfo(&lock_holders_sbuf);
+
DescribeLockTag(&buf, &locallock->tag.lock);
modename = GetLockmodeName(locallock->tag.lock.locktag_lockmethodid,
lockmode);
@@ -1211,10 +1221,67 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
msecs = secs * 1000 + usecs / 1000;
usecs = usecs % 1000;
+ /*
+ * we loop over the lock's procLocks to gather a list of all
+ * holders and waiters. Thus we will be able to provide more
+ * detailed information for lock debugging purposes.
+ *
+ * lock->procLocks contains all processes which hold or wait for
+ * this lock.
+ */
+
+ LWLockAcquire(partitionLock, LW_SHARED);
+
+ procLocks = &(lock->procLocks);
+ proclock = (PROCLOCK *) SHMQueueNext(procLocks, procLocks,
+ offsetof(PROCLOCK, lockLink));
+
+ while (proclock)
+ {
+ /*
+ * we are a waiter if myProc->waitProcLock == proclock; we are
+ * a holder if it is NULL or something different
+ */
+ if (proclock->tag.myProc->waitProcLock == proclock)
+ {
+ if (first_waiter)
+ {
+ appendStringInfo(&lock_waiters_sbuf, "%d",
+ proclock->tag.myProc->pid);
+ first_waiter = false;
+ }
+ else
+ appendStringInfo(&lock_waiters_sbuf, ", %d",
+ proclock->tag.myProc->pid);
+ }
+ else
+ {
+ if (first_holder)
+ {
+ appendStringInfo(&lock_holders_sbuf, "%d",
+ proclock->tag.myProc->pid);
+ first_holder = false;
+ }
+ else
+ appendStringInfo(&lock_holders_sbuf, ", %d",
+ proclock->tag.myProc->pid);
+
+ lockHoldersNum++;
+ }
+
+ proclock = (PROCLOCK *) SHMQueueNext(procLocks, &proclock->lockLink,
+ offsetof(PROCLOCK, lockLink));
+ }
+
+ LWLockRelease(partitionLock);
+
if (deadlock_state == DS_SOFT_DEADLOCK)
ereport(LOG,
(errmsg("process %d avoided deadlock for %s on %s by rearranging queue order after %ld.%03d ms",
- MyProcPid, modename, buf.data, msecs, usecs)));
+ MyProcPid, modename, buf.data, msecs, usecs),
+ (errdetail_log_plural("Process holding the lock: %s. Request queue: %s.",
+ "Processes holding the lock: %s. Request queue: %s.",
+ lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
else if (deadlock_state == DS_HARD_DEADLOCK)
{
/*
@@ -1226,13 +1293,19 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
*/
ereport(LOG,
(errmsg("process %d detected deadlock while waiting for %s on %s after %ld.%03d ms",
- MyProcPid, modename, buf.data, msecs, usecs)));
+ MyProcPid, modename, buf.data, msecs, usecs),
+ (errdetail_log_plural("Process holding the lock: %s. Request queue: %s.",
+ "Processes holding lock: %s. Request queue: %s.",
+ lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
}
if (myWaitStatus == STATUS_WAITING)
ereport(LOG,
(errmsg("process %d still waiting for %s on %s after %ld.%03d ms",
- MyProcPid, modename, buf.data, msecs, usecs)));
+ MyProcPid, modename, buf.data, msecs, usecs),
+ (errdetail_log_plural("Process holding the lock: %s. Request queue: %s.",
+ "Processes holding the lock: %s. Request queue: %s.",
+ lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
else if (myWaitStatus == STATUS_OK)
ereport(LOG,
(errmsg("process %d acquired %s on %s after %ld.%03d ms",
@@ -1252,7 +1325,10 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
if (deadlock_state != DS_HARD_DEADLOCK)
ereport(LOG,
(errmsg("process %d failed to acquire %s on %s after %ld.%03d ms",
- MyProcPid, modename, buf.data, msecs, usecs)));
+ MyProcPid, modename, buf.data, msecs, usecs),
+ (errdetail_log_plural("Process holding the lock: %s. Request queue: %s.",
+ "Processes holding the lock: %s. Request queue: %s.",
+ lockHoldersNum, lock_holders_sbuf.data, lock_waiters_sbuf.data))));
}
/*
@@ -1262,6 +1338,8 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
deadlock_state = DS_NO_DEADLOCK;
pfree(buf.data);
+ pfree(lock_holders_sbuf.data);
+ pfree(lock_waiters_sbuf.data);
}
} while (myWaitStatus == STATUS_WAITING);
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 8705586..d28b749 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -937,6 +937,28 @@ errdetail_log(const char *fmt,...)
return 0; /* return value does not matter */
}
+/*
+ * errdetail_log_plural --- add a detail_log error message text to the current error
+ * with support for pluralization of the message text
+ */
+int
+errdetail_log_plural(const char *fmt_singular, const char *fmt_plural,
+ unsigned long n,...)
+{
+ ErrorData *edata = &errordata[errordata_stack_depth];
+ MemoryContext oldcontext;
+
+ recursion_depth++;
+ CHECK_STACK_DEPTH();
+ oldcontext = MemoryContextSwitchTo(edata->assoc_context);
+
+ EVALUATE_MESSAGE_PLURAL(edata->domain, detail_log, false);
+
+ MemoryContextSwitchTo(oldcontext);
+ recursion_depth--;
+ return 0; /* return value does not matter */
+}
+
/*
* errdetail_plural --- add a detail error message text to the current error,
diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index d7916c2..427d52d 100644
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -182,6 +182,14 @@ errdetail_log(const char *fmt,...)
__attribute__((format(PG_PRINTF_ATTRIBUTE, 1, 2)));
extern int
+errdetail_log_plural(const char *fmt_singular, const char *fmt_plural,
+ unsigned long n,...)
+/* This extension allows gcc to check the format string for consistency with
+ the supplied arguments. */
+__attribute__((format(PG_PRINTF_ATTRIBUTE, 1, 4)))
+__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 4)));
+
+extern int
errdetail_plural(const char *fmt_singular, const char *fmt_plural,
unsigned long n,...)
/* This extension allows gcc to check the format string for consistency with
pgpiZzW1fJ_qs.pgp
Description: PGP signature
