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Commita40cff8

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Move RecoveryLockList into a hash table.
Standbys frequently need to release all locks held by a given xid.Instead of searching one big list linearly, let's create one listper xid and put them in a hash table, so we can find what we needin O(1) time.Earlier analysis and a prototype were done by David Rowley, thoughthis isn't his patch.Back-patch all the way.Author: Thomas MunroDiagnosed-by: David Rowley, Andres FreundReviewed-by: Andres Freund, Tom Lane, Robert HaasDiscussion:https://postgr.es/m/CAEepm%3D1mL0KiQ2KJ4yuPpLGX94a4Ns_W6TL4EGRouxWibu56pA%40mail.gmail.comDiscussion:https://postgr.es/m/CAKJS1f9vJ841HY%3DwonnLVbfkTWGYWdPN72VMxnArcGCjF3SywA%40mail.gmail.com
1 parentc672d70 commita40cff8

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1 file changed

+92
-83
lines changed

1 file changed

+92
-83
lines changed

‎src/backend/storage/ipc/standby.c

Lines changed: 92 additions & 83 deletions
Original file line numberDiff line numberDiff line change
@@ -29,6 +29,8 @@
2929
#include"storage/procarray.h"
3030
#include"storage/sinvaladt.h"
3131
#include"storage/standby.h"
32+
#include"utils/hsearch.h"
33+
#include"utils/memutils.h"
3234
#include"utils/ps_status.h"
3335
#include"utils/timeout.h"
3436
#include"utils/timestamp.h"
@@ -38,14 +40,22 @@ intvacuum_defer_cleanup_age;
3840
intmax_standby_archive_delay=30*1000;
3941
intmax_standby_streaming_delay=30*1000;
4042

41-
staticList*RecoveryLockList;
43+
staticHTAB*RecoveryLockLists;
4244

4345
staticvoidResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId*waitlist,
4446
ProcSignalReasonreason);
4547
staticvoidSendRecoveryConflictWithBufferPin(ProcSignalReasonreason);
4648
staticXLogRecPtrLogCurrentRunningXacts(RunningTransactionsCurrRunningXacts);
4749
staticvoidLogAccessExclusiveLocks(intnlocks,xl_standby_lock*locks);
4850

51+
/*
52+
* Keep track of all the locks owned by a given transaction.
53+
*/
54+
typedefstructRecoveryLockListsEntry
55+
{
56+
TransactionIdxid;
57+
List*locks;
58+
}RecoveryLockListsEntry;
4959

5060
/*
5161
* InitRecoveryTransactionEnvironment
@@ -63,6 +73,19 @@ void
6373
InitRecoveryTransactionEnvironment(void)
6474
{
6575
VirtualTransactionIdvxid;
76+
HASHCTLhash_ctl;
77+
78+
/*
79+
* Initialize the hash table for tracking the list of locks held by each
80+
* transaction.
81+
*/
82+
memset(&hash_ctl,0,sizeof(hash_ctl));
83+
hash_ctl.keysize=sizeof(TransactionId);
84+
hash_ctl.entrysize=sizeof(RecoveryLockListsEntry);
85+
RecoveryLockLists=hash_create("RecoveryLockLists",
86+
64,
87+
&hash_ctl,
88+
HASH_ELEM |HASH_BLOBS);
6689

6790
/*
6891
* Initialize shared invalidation management for Startup process, being
@@ -107,6 +130,10 @@ ShutdownRecoveryTransactionEnvironment(void)
107130
/* Release all locks the tracked transactions were holding */
108131
StandbyReleaseAllLocks();
109132

133+
/* Destroy the hash table of locks. */
134+
hash_destroy(RecoveryLockLists);
135+
RecoveryLockLists=NULL;
136+
110137
/* Cleanup our VirtualTransaction */
111138
VirtualXactLockTableCleanup();
112139
}
@@ -586,8 +613,8 @@ StandbyLockTimeoutHandler(void)
586613
* We only keep track of AccessExclusiveLocks, which are only ever held by
587614
* one transaction on one relation.
588615
*
589-
* We keep asingle dynamically expandible list of locks in local memory,
590-
*RecoveryLockList, so we can keep track of the various entries made by
616+
* We keep ahash table of lists of locks in local memory keyed by xid,
617+
*RecoveryLockLists, so we can keep track of the various entries made by
591618
* the Startup process's virtual xid in the shared lock table.
592619
*
593620
* List elements use type xl_standby_lock, since the WAL record type exactly
@@ -601,8 +628,10 @@ StandbyLockTimeoutHandler(void)
601628
void
602629
StandbyAcquireAccessExclusiveLock(TransactionIdxid,OiddbOid,OidrelOid)
603630
{
631+
RecoveryLockListsEntry*entry;
604632
xl_standby_lock*newlock;
605633
LOCKTAGlocktag;
634+
boolfound;
606635

607636
/* Already processed? */
608637
if (!TransactionIdIsValid(xid)||
@@ -616,58 +645,68 @@ StandbyAcquireAccessExclusiveLock(TransactionId xid, Oid dbOid, Oid relOid)
616645
/* dbOid is InvalidOid when we are locking a shared relation. */
617646
Assert(OidIsValid(relOid));
618647

648+
/* Create a new list for this xid, if we don't have one already. */
649+
entry=hash_search(RecoveryLockLists,&xid,HASH_ENTER,&found);
650+
if (!found)
651+
{
652+
entry->xid=xid;
653+
entry->locks=NIL;
654+
}
655+
619656
newlock=palloc(sizeof(xl_standby_lock));
620657
newlock->xid=xid;
621658
newlock->dbOid=dbOid;
622659
newlock->relOid=relOid;
623-
RecoveryLockList=lappend(RecoveryLockList,newlock);
660+
entry->locks=lappend(entry->locks,newlock);
624661

625662
SET_LOCKTAG_RELATION(locktag,newlock->dbOid,newlock->relOid);
626663

627664
LockAcquireExtended(&locktag,AccessExclusiveLock, true, false, false);
628665
}
629666

630667
staticvoid
631-
StandbyReleaseLocks(TransactionIdxid)
668+
StandbyReleaseLockList(List*locks)
632669
{
633-
ListCell*cell,
634-
*prev,
635-
*next;
636-
637-
/*
638-
* Release all matching locks and remove them from list
639-
*/
640-
prev=NULL;
641-
for (cell=list_head(RecoveryLockList);cell;cell=next)
670+
while (locks)
642671
{
643-
xl_standby_lock*lock= (xl_standby_lock*)lfirst(cell);
672+
xl_standby_lock*lock= (xl_standby_lock*)linitial(locks);
673+
LOCKTAGlocktag;
674+
elog(trace_recovery(DEBUG4),
675+
"releasing recovery lock: xid %u db %u rel %u",
676+
lock->xid,lock->dbOid,lock->relOid);
677+
SET_LOCKTAG_RELATION(locktag,lock->dbOid,lock->relOid);
678+
if (!LockRelease(&locktag,AccessExclusiveLock, true))
679+
{
680+
elog(LOG,
681+
"RecoveryLockLists contains entry for lock no longer recorded by lock manager: xid %u database %u relation %u",
682+
lock->xid,lock->dbOid,lock->relOid);
683+
Assert(false);
684+
}
685+
pfree(lock);
686+
locks=list_delete_first(locks);
687+
}
688+
}
644689

645-
next=lnext(cell);
690+
staticvoid
691+
StandbyReleaseLocks(TransactionIdxid)
692+
{
693+
RecoveryLockListsEntry*entry;
646694

647-
if (!TransactionIdIsValid(xid)||lock->xid==xid)
695+
if (TransactionIdIsValid(xid))
696+
{
697+
if ((entry=hash_search(RecoveryLockLists,&xid,HASH_FIND,NULL)))
648698
{
649-
LOCKTAGlocktag;
650-
651-
elog(trace_recovery(DEBUG4),
652-
"releasing recovery lock: xid %u db %u rel %u",
653-
lock->xid,lock->dbOid,lock->relOid);
654-
SET_LOCKTAG_RELATION(locktag,lock->dbOid,lock->relOid);
655-
if (!LockRelease(&locktag,AccessExclusiveLock, true))
656-
elog(LOG,
657-
"RecoveryLockList contains entry for lock no longer recorded by lock manager: xid %u database %u relation %u",
658-
lock->xid,lock->dbOid,lock->relOid);
659-
660-
RecoveryLockList=list_delete_cell(RecoveryLockList,cell,prev);
661-
pfree(lock);
699+
StandbyReleaseLockList(entry->locks);
700+
hash_search(RecoveryLockLists,entry,HASH_REMOVE,NULL);
662701
}
663-
else
664-
prev=cell;
665702
}
703+
else
704+
StandbyReleaseAllLocks();
666705
}
667706

668707
/*
669708
* Release locks for a transaction tree, starting at xid down, from
670-
*RecoveryLockList.
709+
*RecoveryLockLists.
671710
*
672711
* Called during WAL replay of COMMIT/ROLLBACK when in hot standby mode,
673712
* to remove any AccessExclusiveLocks requested by a transaction.
@@ -689,30 +728,16 @@ StandbyReleaseLockTree(TransactionId xid, int nsubxids, TransactionId *subxids)
689728
void
690729
StandbyReleaseAllLocks(void)
691730
{
692-
ListCell*cell,
693-
*prev,
694-
*next;
695-
LOCKTAGlocktag;
731+
HASH_SEQ_STATUSstatus;
732+
RecoveryLockListsEntry*entry;
696733

697734
elog(trace_recovery(DEBUG2),"release all standby locks");
698735

699-
prev=NULL;
700-
for (cell=list_head(RecoveryLockList);cell;cell=next)
736+
hash_seq_init(&status,RecoveryLockLists);
737+
while ((entry=hash_seq_search(&status)))
701738
{
702-
xl_standby_lock*lock= (xl_standby_lock*)lfirst(cell);
703-
704-
next=lnext(cell);
705-
706-
elog(trace_recovery(DEBUG4),
707-
"releasing recovery lock: xid %u db %u rel %u",
708-
lock->xid,lock->dbOid,lock->relOid);
709-
SET_LOCKTAG_RELATION(locktag,lock->dbOid,lock->relOid);
710-
if (!LockRelease(&locktag,AccessExclusiveLock, true))
711-
elog(LOG,
712-
"RecoveryLockList contains entry for lock no longer recorded by lock manager: xid %u database %u relation %u",
713-
lock->xid,lock->dbOid,lock->relOid);
714-
RecoveryLockList=list_delete_cell(RecoveryLockList,cell,prev);
715-
pfree(lock);
739+
StandbyReleaseLockList(entry->locks);
740+
hash_search(RecoveryLockLists,entry,HASH_REMOVE,NULL);
716741
}
717742
}
718743

@@ -724,41 +749,25 @@ StandbyReleaseAllLocks(void)
724749
void
725750
StandbyReleaseOldLocks(TransactionIdoldxid)
726751
{
727-
ListCell*cell,
728-
*prev,
729-
*next;
730-
LOCKTAGlocktag;
752+
HASH_SEQ_STATUSstatus;
753+
RecoveryLockListsEntry*entry;
731754

732-
prev=NULL;
733-
for (cell=list_head(RecoveryLockList);cell;cell=next)
755+
hash_seq_init(&status,RecoveryLockLists);
756+
while ((entry=hash_seq_search(&status)))
734757
{
735-
xl_standby_lock*lock= (xl_standby_lock*)lfirst(cell);
736-
boolremove= false;
737-
738-
next=lnext(cell);
758+
Assert(TransactionIdIsValid(entry->xid));
739759

740-
Assert(TransactionIdIsValid(lock->xid));
760+
/* Skip if prepared transaction. */
761+
if (StandbyTransactionIdIsPrepared(entry->xid))
762+
continue;
741763

742-
if (StandbyTransactionIdIsPrepared(lock->xid))
743-
remove= false;
744-
elseif (TransactionIdPrecedes(lock->xid,oldxid))
745-
remove= true;
764+
/* Skip if >= oldxid. */
765+
if (!TransactionIdPrecedes(entry->xid,oldxid))
766+
continue;
746767

747-
if (remove)
748-
{
749-
elog(trace_recovery(DEBUG4),
750-
"releasing recovery lock: xid %u db %u rel %u",
751-
lock->xid,lock->dbOid,lock->relOid);
752-
SET_LOCKTAG_RELATION(locktag,lock->dbOid,lock->relOid);
753-
if (!LockRelease(&locktag,AccessExclusiveLock, true))
754-
elog(LOG,
755-
"RecoveryLockList contains entry for lock no longer recorded by lock manager: xid %u database %u relation %u",
756-
lock->xid,lock->dbOid,lock->relOid);
757-
RecoveryLockList=list_delete_cell(RecoveryLockList,cell,prev);
758-
pfree(lock);
759-
}
760-
else
761-
prev=cell;
768+
/* Remove all locks and hash table entry. */
769+
StandbyReleaseLockList(entry->locks);
770+
hash_search(RecoveryLockLists,entry,HASH_REMOVE,NULL);
762771
}
763772
}
764773

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