diff --git a/contrib/amcheck/expected/check_btree.out b/contrib/amcheck/expected/check_btree.out
index 13848b7449..5a3f1ef737 100644
--- a/contrib/amcheck/expected/check_btree.out
+++ b/contrib/amcheck/expected/check_btree.out
@@ -97,8 +97,8 @@ SELECT bt_index_parent_check('bttest_b_idx');
SELECT * FROM pg_locks
WHERE relation = ANY(ARRAY['bttest_a', 'bttest_a_idx', 'bttest_b', 'bttest_b_idx']::regclass[])
AND pid = pg_backend_pid();
- locktype | database | relation | page | tuple | virtualxid | transactionid | classid | objid | objsubid | virtualtransaction | pid | mode | granted | fastpath
-----------+----------+----------+------+-------+------------+---------------+---------+-------+----------+--------------------+-----+------+---------+----------
+ locktype | database | relation | page | tuple | virtualxid | transactionid | classid | objid | objsubid | virtualtransaction | pid | mode | granted | fastpath | waitstart
+----------+----------+----------+------+-------+------------+---------------+---------+-------+----------+--------------------+-----+------+---------+----------+-----------
(0 rows)
COMMIT;
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index ea222c0464..9085d2e64c 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -10604,6 +10604,19 @@ SCRAM-SHA-256$<iteration count>:&l
lock table
+
+
+
+ waitstart timestamptz
+
+
+ Time when the server process started waiting for this lock,
+ or null if the lock is held.
+ Note that this can be null for a very short period of time after
+ the wait started even though granted
+ is false.
+
+
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index fc18b77832..70d22577ce 100644
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -873,8 +873,15 @@ PGPROC *
TwoPhaseGetDummyProc(TransactionId xid, bool lock_held)
{
GlobalTransaction gxact = TwoPhaseGetGXact(xid, lock_held);
+ PGPROC *dummy = &ProcGlobal->allProcs[gxact->pgprocno];
- return &ProcGlobal->allProcs[gxact->pgprocno];
+ /*
+ * Initialize atomic variable in dummy proc so that GetLockStatusData()
+ * can read it later.
+ */
+ pg_atomic_init_u64(&dummy->waitStart, 0);
+
+ return dummy;
}
/************************************************************************/
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index 39a30c00f7..5877a60715 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -540,12 +540,34 @@ void
ResolveRecoveryConflictWithLock(LOCKTAG locktag, bool logging_conflict)
{
TimestampTz ltime;
+ TimestampTz now;
Assert(InHotStandby);
ltime = GetStandbyLimitTime();
+ now = GetCurrentTimestamp();
- if (GetCurrentTimestamp() >= ltime && ltime != 0)
+ /*
+ * Update waitStart if first time through after the startup process
+ * started waiting for the lock. It should not be updated every time
+ * ResolveRecoveryConflictWithLock() is called during the wait.
+ *
+ * Use the current time obtained for comparison with ltime as waitStart
+ * (i.e., the time when this process started waiting for the lock). Since
+ * getting the current time newly can cause overhead, we reuse the
+ * already-obtained time to avoid that overhead.
+ *
+ * Note that waitStart is updated without holding the lock table's
+ * partition lock, to avoid the overhead by additional lock acquisition.
+ * This can cause "waitstart" in pg_locks to become NULL for a very short
+ * period of time after the wait started even though "granted" is false.
+ * This is OK in practice because we can assume that users are likely to
+ * look at "waitstart" when waiting for the lock for a long time.
+ */
+ if (pg_atomic_read_u64(&MyProc->waitStart) == 0)
+ pg_atomic_write_u64(&MyProc->waitStart, now);
+
+ if (now >= ltime && ltime != 0)
{
/*
* We're already behind, so clear a path as quickly as possible.
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 79c1cf9b8b..108b4d9023 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -3619,6 +3619,12 @@ GetLockStatusData(void)
instance->leaderPid = proc->pid;
instance->fastpath = true;
+ /*
+ * Successfully taking fast path lock means there were no
+ * conflicting locks.
+ */
+ instance->waitStart = 0;
+
el++;
}
@@ -3646,6 +3652,7 @@ GetLockStatusData(void)
instance->pid = proc->pid;
instance->leaderPid = proc->pid;
instance->fastpath = true;
+ instance->waitStart = 0;
el++;
}
@@ -3698,6 +3705,7 @@ GetLockStatusData(void)
instance->pid = proc->pid;
instance->leaderPid = proclock->groupLeader->pid;
instance->fastpath = false;
+ instance->waitStart = (TimestampTz) pg_atomic_read_u64(&proc->waitStart);
el++;
}
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index c87ffc6549..0884909a22 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -402,6 +402,7 @@ InitProcess(void)
MyProc->lwWaitMode = 0;
MyProc->waitLock = NULL;
MyProc->waitProcLock = NULL;
+ pg_atomic_init_u64(&MyProc->waitStart, 0);
#ifdef USE_ASSERT_CHECKING
{
int i;
@@ -580,6 +581,7 @@ InitAuxiliaryProcess(void)
MyProc->lwWaitMode = 0;
MyProc->waitLock = NULL;
MyProc->waitProcLock = NULL;
+ pg_atomic_init_u64(&MyProc->waitStart, 0);
#ifdef USE_ASSERT_CHECKING
{
int i;
@@ -1262,6 +1264,23 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
}
else
enable_timeout_after(DEADLOCK_TIMEOUT, DeadlockTimeout);
+
+ /*
+ * Use the current time obtained for the deadlock timeout timer as
+ * waitStart (i.e., the time when this process started waiting for the
+ * lock). Since getting the current time newly can cause overhead, we
+ * reuse the already-obtained time to avoid that overhead.
+ *
+ * Note that waitStart is updated without holding the lock table's
+ * partition lock, to avoid the overhead by additional lock
+ * acquisition. This can cause "waitstart" in pg_locks to become NULL
+ * for a very short period of time after the wait started even though
+ * "granted" is false. This is OK in practice because we can assume
+ * that users are likely to look at "waitstart" when waiting for the
+ * lock for a long time.
+ */
+ pg_atomic_write_u64(&MyProc->waitStart,
+ get_timeout_start_time(DEADLOCK_TIMEOUT));
}
else if (log_recovery_conflict_waits)
{
@@ -1678,6 +1697,7 @@ ProcWakeup(PGPROC *proc, ProcWaitStatus waitStatus)
proc->waitLock = NULL;
proc->waitProcLock = NULL;
proc->waitStatus = waitStatus;
+ pg_atomic_write_u64(&MyProc->waitStart, 0);
/* And awaken it */
SetLatch(&proc->procLatch);
diff --git a/src/backend/utils/adt/lockfuncs.c b/src/backend/utils/adt/lockfuncs.c
index b1cf5b79a7..97f0265c12 100644
--- a/src/backend/utils/adt/lockfuncs.c
+++ b/src/backend/utils/adt/lockfuncs.c
@@ -63,7 +63,7 @@ typedef struct
} PG_Lock_Status;
/* Number of columns in pg_locks output */
-#define NUM_LOCK_STATUS_COLUMNS 15
+#define NUM_LOCK_STATUS_COLUMNS 16
/*
* VXIDGetDatum - Construct a text representation of a VXID
@@ -142,6 +142,8 @@ pg_lock_status(PG_FUNCTION_ARGS)
BOOLOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 15, "fastpath",
BOOLOID, -1, 0);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 16, "waitstart",
+ TIMESTAMPTZOID, -1, 0);
funcctx->tuple_desc = BlessTupleDesc(tupdesc);
@@ -336,6 +338,10 @@ pg_lock_status(PG_FUNCTION_ARGS)
values[12] = CStringGetTextDatum(GetLockmodeName(instance->locktag.locktag_lockmethodid, mode));
values[13] = BoolGetDatum(granted);
values[14] = BoolGetDatum(instance->fastpath);
+ if (!granted && instance->waitStart != 0)
+ values[15] = TimestampTzGetDatum(instance->waitStart);
+ else
+ nulls[15] = true;
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
result = HeapTupleGetDatum(tuple);
@@ -406,6 +412,7 @@ pg_lock_status(PG_FUNCTION_ARGS)
values[12] = CStringGetTextDatum("SIReadLock");
values[13] = BoolGetDatum(true);
values[14] = BoolGetDatum(false);
+ nulls[15] = true;
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
result = HeapTupleGetDatum(tuple);
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 638830aaac..c1a5dd4ee7 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -53,6 +53,6 @@
*/
/* yyyymmddN */
-#define CATALOG_VERSION_NO 202102021
+#define CATALOG_VERSION_NO 202102091
#endif
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 4e0c9be58c..1487710d59 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5994,9 +5994,9 @@
{ oid => '1371', descr => 'view system lock information',
proname => 'pg_lock_status', prorows => '1000', proretset => 't',
provolatile => 'v', prorettype => 'record', proargtypes => '',
- proallargtypes => '{text,oid,oid,int4,int2,text,xid,oid,oid,int2,text,int4,text,bool,bool}',
- proargmodes => '{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
- proargnames => '{locktype,database,relation,page,tuple,virtualxid,transactionid,classid,objid,objsubid,virtualtransaction,pid,mode,granted,fastpath}',
+ proallargtypes => '{text,oid,oid,int4,int2,text,xid,oid,oid,int2,text,int4,text,bool,bool,timestamptz}',
+ proargmodes => '{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
+ proargnames => '{locktype,database,relation,page,tuple,virtualxid,transactionid,classid,objid,objsubid,virtualtransaction,pid,mode,granted,fastpath,waitstart}',
prosrc => 'pg_lock_status' },
{ oid => '2561',
descr => 'get array of PIDs of sessions blocking specified backend PID from acquiring a heavyweight lock',
diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h
index 68a3487d49..9b2a421c32 100644
--- a/src/include/storage/lock.h
+++ b/src/include/storage/lock.h
@@ -22,6 +22,7 @@
#include "storage/lockdefs.h"
#include "storage/lwlock.h"
#include "storage/shmem.h"
+#include "utils/timestamp.h"
/* struct PGPROC is declared in proc.h, but must forward-reference it */
typedef struct PGPROC PGPROC;
@@ -446,6 +447,8 @@ typedef struct LockInstanceData
LOCKMODE waitLockMode; /* lock awaited by this PGPROC, if any */
BackendId backend; /* backend ID of this PGPROC */
LocalTransactionId lxid; /* local transaction ID of this PGPROC */
+ TimestampTz waitStart; /* time at which this PGPROC started waiting
+ * for lock */
int pid; /* pid of this PGPROC */
int leaderPid; /* pid of group leader; = pid if no group */
bool fastpath; /* taken via fastpath? */
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 683ab64f76..a777cb64a1 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -181,6 +181,8 @@ struct PGPROC
LOCKMODE waitLockMode; /* type of lock we're waiting for */
LOCKMASK heldLocks; /* bitmask for lock types already held on this
* lock object by this backend */
+ pg_atomic_uint64 waitStart; /* time at which wait for lock acquisition
+ * started */
bool delayChkpt; /* true if this proc delays checkpoint start */
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index b632d9f2ea..10a1f34ebc 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1394,8 +1394,9 @@ pg_locks| SELECT l.locktype,
l.pid,
l.mode,
l.granted,
- l.fastpath
- FROM pg_lock_status() l(locktype, database, relation, page, tuple, virtualxid, transactionid, classid, objid, objsubid, virtualtransaction, pid, mode, granted, fastpath);
+ l.fastpath,
+ l.waitstart
+ FROM pg_lock_status() l(locktype, database, relation, page, tuple, virtualxid, transactionid, classid, objid, objsubid, virtualtransaction, pid, mode, granted, fastpath, waitstart);
pg_matviews| SELECT n.nspname AS schemaname,
c.relname AS matviewname,
pg_get_userbyid(c.relowner) AS matviewowner,