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Setup error context callback for transaction lock waits 

With this in place, a session blocking behind another one because of
tuple locks will get a context line mentioning the relation name, tuple
TID, and operation being done on tuple.  For example:

LOG:  process 11367 still waiting for ShareLock on transaction 717 after 1000.108 ms
DETAIL:  Process holding the lock: 11366. Wait queue: 11367.
CONTEXT:  while updating tuple (0,2) in relation "foo"
STATEMENT:  UPDATE foo SET value = 3;

Most usefully, the new line is displayed by log entries due to
log_lock_waits, although of course it will be printed by any other log
message as well.

Author: Christian Kruse, some tweaks by Álvaro Herrera
Reviewed-by: Amit Kapila, Andres Freund, Tom Lane, Robert Haas
This commit is contained in:
Alvaro Herrera 2014-03-19 15:10:36 -03:00
parent ea8c7e9054
commit f88d4cfc9d
9 changed files with 189 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

80
src/backend/access/heap/heapam.c
View File

@ -105,11 +105,12 @@ static void GetMultiXactIdHintBits(MultiXactId multi, uint16 *new_infomask,
uint16 *new_infomask2);
static TransactionId MultiXactIdGetUpdateXid(TransactionId xmax,
uint16 t_infomask);
static void MultiXactIdWait(MultiXactId multi, MultiXactStatus status,
int *remaining, uint16 infomask);
static bool ConditionalMultiXactIdWait(MultiXactId multi,
MultiXactStatus status, int *remaining,
uint16 infomask);
static void MultiXactIdWait(MultiXactId multi, MultiXactStatus status, uint16 infomask,
Relation rel, ItemPointer ctid, XLTW_Oper oper,
int *remaining);
static bool ConditionalMultiXactIdWait(MultiXactId multi, MultiXactStatus status,
uint16 infomask, Relation rel, ItemPointer ctid,
XLTW_Oper oper, int *remaining);
static XLogRecPtr log_heap_new_cid(Relation relation, HeapTuple tup);
static HeapTuple ExtractReplicaIdentity(Relation rel, HeapTuple tup, bool key_modified,
bool *copy);
@ -2714,8 +2715,9 @@ l1:
if (infomask & HEAP_XMAX_IS_MULTI)
{
/* wait for multixact */
MultiXactIdWait((MultiXactId) xwait, MultiXactStatusUpdate,
NULL, infomask);
MultiXactIdWait((MultiXactId) xwait, MultiXactStatusUpdate, infomask,
relation, &tp.t_data->t_ctid, XLTW_Delete,
NULL);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
@ -2741,7 +2743,7 @@ l1:
else
{
/* wait for regular transaction to end */
XactLockTableWait(xwait);
XactLockTableWait(xwait, relation, &tp.t_data->t_ctid, XLTW_Delete);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
@ -3266,8 +3268,9 @@ l2:
int remain;
/* wait for multixact */
MultiXactIdWait((MultiXactId) xwait, mxact_status, &remain,
infomask);
MultiXactIdWait((MultiXactId) xwait, mxact_status, infomask,
relation, &oldtup.t_data->t_ctid, XLTW_Update,
&remain);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
@ -3341,7 +3344,8 @@ l2:
else
{
/* wait for regular transaction to end */
XactLockTableWait(xwait);
XactLockTableWait(xwait, relation, &oldtup.t_data->t_ctid,
XLTW_Update);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
@ -4402,14 +4406,18 @@ l3:
if (nowait)
{
if (!ConditionalMultiXactIdWait((MultiXactId) xwait,
status, NULL, infomask))
status, infomask, relation,
&tuple->t_data->t_ctid,
XLTW_Lock, NULL))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on row in relation \"%s\"",
RelationGetRelationName(relation))));
}
else
MultiXactIdWait((MultiXactId) xwait, status, NULL, infomask);
MultiXactIdWait((MultiXactId) xwait, status, infomask,
relation, &tuple->t_data->t_ctid,
XLTW_Lock, NULL);
/* if there are updates, follow the update chain */
if (follow_updates &&
@ -4464,7 +4472,8 @@ l3:
RelationGetRelationName(relation))));
}
else
XactLockTableWait(xwait);
XactLockTableWait(xwait, relation, &tuple->t_data->t_ctid,
XLTW_Lock);
/* if there are updates, follow the update chain */
if (follow_updates &&
@ -5151,7 +5160,9 @@ l4:
if (needwait)
{
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
XactLockTableWait(members[i].xid);
XactLockTableWait(members[i].xid, rel,
&mytup.t_data->t_ctid,
XLTW_LockUpdated);
pfree(members);
goto l4;
}
@ -5211,7 +5222,8 @@ l4:
if (needwait)
{
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
XactLockTableWait(rawxmax);
XactLockTableWait(rawxmax, rel, &mytup.t_data->t_ctid,
XLTW_LockUpdated);
goto l4;
}
if (res != HeapTupleMayBeUpdated)
@ -6076,6 +6088,15 @@ HeapTupleGetUpdateXid(HeapTupleHeader tuple)
* Do_MultiXactIdWait
* Actual implementation for the two functions below.
*
* 'multi', 'status' and 'infomask' indicate what to sleep on (the status is
* needed to ensure we only sleep on conflicting members, and the infomask is
* used to optimize multixact access in case it's a lock-only multi); 'nowait'
* indicates whether to use conditional lock acquisition, to allow callers to
* fail if lock is unavailable. 'rel', 'ctid' and 'oper' are used to set up
* context information for error messages. 'remaining', if not NULL, receives
* the number of members that are still running, including any (non-aborted)
* subtransactions of our own transaction.
*
* We do this by sleeping on each member using XactLockTableWait. Any
* members that belong to the current backend are *not* waited for, however;
* this would not merely be useless but would lead to Assert failure inside
@ -6093,7 +6114,9 @@ HeapTupleGetUpdateXid(HeapTupleHeader tuple)
*/
static bool
Do_MultiXactIdWait(MultiXactId multi, MultiXactStatus status,
int *remaining, uint16 infomask, bool nowait)
uint16 infomask, bool nowait,
Relation rel, ItemPointer ctid, XLTW_Oper oper,
int *remaining)
{
bool allow_old;
bool result = true;
@ -6130,6 +6153,12 @@ Do_MultiXactIdWait(MultiXactId multi, MultiXactStatus status,
/*
* This member conflicts with our multi, so we have to sleep (or
* return failure, if asked to avoid waiting.)
*
* Note that we don't set up an error context callback ourselves,
* but instead we pass the info down to XactLockTableWait. This
* might seem a bit wasteful because the context is set up and
* tore down for each member of the multixact, but in reality it
* should be barely noticeable, and it avoids duplicate code.
*/
if (nowait)
{
@ -6138,7 +6167,7 @@ Do_MultiXactIdWait(MultiXactId multi, MultiXactStatus status,
break;
}
else
XactLockTableWait(memxid);
XactLockTableWait(memxid, rel, ctid, oper);
}
pfree(members);
@ -6159,13 +6188,14 @@ Do_MultiXactIdWait(MultiXactId multi, MultiXactStatus status,
*
* We return (in *remaining, if not NULL) the number of members that are still
* running, including any (non-aborted) subtransactions of our own transaction.
*
*/
static void
MultiXactIdWait(MultiXactId multi, MultiXactStatus status,
int *remaining, uint16 infomask)
MultiXactIdWait(MultiXactId multi, MultiXactStatus status, uint16 infomask,
Relation rel, ItemPointer ctid, XLTW_Oper oper,
int *remaining)
{
Do_MultiXactIdWait(multi, status, remaining, infomask, false);
(void) Do_MultiXactIdWait(multi, status, infomask, false,
rel, ctid, oper, remaining);
}
/*
@ -6183,9 +6213,11 @@ MultiXactIdWait(MultiXactId multi, MultiXactStatus status,
*/
static bool
ConditionalMultiXactIdWait(MultiXactId multi, MultiXactStatus status,
int *remaining, uint16 infomask)
uint16 infomask, Relation rel, ItemPointer ctid,
XLTW_Oper oper, int *remaining)
{
return Do_MultiXactIdWait(multi, status, remaining, infomask, true);
return Do_MultiXactIdWait(multi, status, infomask, true,
rel, ctid, oper, remaining);
}
/*

2
src/backend/access/nbtree/nbtinsert.c
View File

@ -168,7 +168,7 @@ top:
{
/* Have to wait for the other guy ... */
_bt_relbuf(rel, buf);
XactLockTableWait(xwait);
XactLockTableWait(xwait, rel, &itup->t_tid, XLTW_InsertIndex);
/* start over... */
_bt_freestack(stack);
goto top;

8
src/backend/catalog/index.c
View File

@ -2295,7 +2295,9 @@ IndexBuildHeapScan(Relation heapRelation,
* Must drop the lock on the buffer before we wait
*/
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
XactLockTableWait(xwait);
XactLockTableWait(xwait, heapRelation,
&heapTuple->t_data->t_ctid,
XLTW_InsertIndexUnique);
goto recheck;
}
}
@ -2341,7 +2343,9 @@ IndexBuildHeapScan(Relation heapRelation,
* Must drop the lock on the buffer before we wait
*/
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
XactLockTableWait(xwait);
XactLockTableWait(xwait, heapRelation,
&heapTuple->t_data->t_ctid,
XLTW_InsertIndexUnique);
goto recheck;
}

4
src/backend/executor/execMain.c
View File

@ -1982,7 +1982,9 @@ EvalPlanQualFetch(EState *estate, Relation relation, int lockmode,
if (TransactionIdIsValid(SnapshotDirty.xmax))
{
ReleaseBuffer(buffer);
XactLockTableWait(SnapshotDirty.xmax);
XactLockTableWait(SnapshotDirty.xmax,
relation, &tuple.t_data->t_ctid,
XLTW_FetchUpdated);
continue; /* loop back to repeat heap_fetch */
}

3
src/backend/executor/execUtils.c
View File

@ -1307,7 +1307,8 @@ retry:
if (TransactionIdIsValid(xwait))
{
index_endscan(index_scan);
XactLockTableWait(xwait);
XactLockTableWait(xwait, heap, &tup->t_data->t_ctid,
XLTW_RecheckExclusionConstr);
goto retry;
}

2
src/backend/replication/logical/snapbuild.c
View File

@ -1343,7 +1343,7 @@ SnapBuildFindSnapshot(SnapBuild *builder, XLogRecPtr lsn, xl_running_xacts *runn
if (TransactionIdIsCurrentTransactionId(xid))
elog(ERROR, "waiting for ourselves");
XactLockTableWait(xid);
XactLockTableWait(xid, NULL, NULL, XLTW_None);
}
/* nothing could have built up so far, so don't perform cleanup */

102
src/backend/storage/lmgr/lmgr.c
View File

@ -25,6 +25,21 @@
#include "utils/inval.h"
/*
* Struct to hold context info for transaction lock waits.
*
* 'oper' is the operation that needs to wait for the other transaction; 'rel'
* and 'ctid' specify the address of the tuple being waited for.
*/
typedef struct XactLockTableWaitInfo
{
XLTW_Oper oper;
Relation rel;
ItemPointer ctid;
} XactLockTableWaitInfo;
static void XactLockTableWaitErrorCb(void *arg);
/*
* RelationInitLockInfo
* Initializes the lock information in a relation descriptor.
@ -471,7 +486,9 @@ XactLockTableDelete(TransactionId xid)
/*
* XactLockTableWait
*
* Wait for the specified transaction to commit or abort.
* Wait for the specified transaction to commit or abort. If an operation
* is specified, an error context callback is set up. If 'oper' is passed as
* None, no error context callback is set up.
*
* Note that this does the right thing for subtransactions: if we wait on a
* subtransaction, we will exit as soon as it aborts or its top parent commits.
@ -481,9 +498,31 @@ XactLockTableDelete(TransactionId xid)
* and if so wait for its parent.
*/
void
XactLockTableWait(TransactionId xid)
XactLockTableWait(TransactionId xid, Relation rel, ItemPointer ctid,
XLTW_Oper oper)
{
LOCKTAG tag;
XactLockTableWaitInfo info;
ErrorContextCallback callback;
/*
* If an operation is specified, set up our verbose error context
* callback.
*/
if (oper != XLTW_None)
{
Assert(RelationIsValid(rel));
Assert(ItemPointerIsValid(ctid));
info.rel = rel;
info.ctid = ctid;
info.oper = oper;
callback.callback = XactLockTableWaitErrorCb;
callback.arg = &info;
callback.previous = error_context_stack;
error_context_stack = &callback;
}
for (;;)
{
@ -500,6 +539,9 @@ XactLockTableWait(TransactionId xid)
break;
xid = SubTransGetParent(xid);
}
if (oper != XLTW_None)
error_context_stack = callback.previous;
}
/*
@ -533,6 +575,62 @@ ConditionalXactLockTableWait(TransactionId xid)
return true;
}
/*
* XactLockTableWaitErrorContextCb
* Error context callback for transaction lock waits.
*/
static void
XactLockTableWaitErrorCb(void *arg)
{
XactLockTableWaitInfo *info = (XactLockTableWaitInfo *) arg;
/*
* We would like to print schema name too, but that would require a
* syscache lookup.
*/
if (info->oper != XLTW_None &&
ItemPointerIsValid(info->ctid) && RelationIsValid(info->rel))
{
const char *cxt;
switch (info->oper)
{
case XLTW_Update:
cxt = gettext_noop("while updating tuple (%u,%u) in relation \"%s\"");
break;
case XLTW_Delete:
cxt = gettext_noop("while deleting tuple (%u,%u) in relation \"%s\"");
break;
case XLTW_Lock:
cxt = gettext_noop("while locking tuple (%u,%u) in relation \"%s\"");
break;
case XLTW_LockUpdated:
cxt = gettext_noop("while locking updated version (%u,%u) of tuple in relation \"%s\"");
break;
case XLTW_InsertIndex:
cxt = gettext_noop("while inserting index tuple (%u,%u) in relation \"%s\"");
break;
case XLTW_InsertIndexUnique:
cxt = gettext_noop("while checking uniqueness of tuple (%u,%u) in relation \"%s\"");
break;
case XLTW_FetchUpdated:
cxt = gettext_noop("while rechecking updated tuple (%u,%u) in relation \"%s\"");
break;
case XLTW_RecheckExclusionConstr:
cxt = gettext_noop("while checking exclusion constraint on tuple (%u,%u) in relation \"%s\"");
break;
default:
return;
}
errcontext(cxt,
ItemPointerGetBlockNumber(info->ctid),
ItemPointerGetOffsetNumber(info->ctid),
RelationGetRelationName(info->rel));
}
}
/*
* WaitForLockersMultiple
* Wait until no transaction holds locks that conflict with the given

17
src/include/storage/lmgr.h
View File

@ -20,6 +20,20 @@
#include "utils/rel.h"
/* XactLockTableWait operations */
typedef enum XLTW_Oper
{
XLTW_None,
XLTW_Update,
XLTW_Delete,
XLTW_Lock,
XLTW_LockUpdated,
XLTW_InsertIndex,
XLTW_InsertIndexUnique,
XLTW_FetchUpdated,
XLTW_RecheckExclusionConstr
} XLTW_Oper;
extern void RelationInitLockInfo(Relation relation);
/* Lock a relation */
@ -54,7 +68,8 @@ extern void UnlockTuple(Relation relation, ItemPointer tid, LOCKMODE lockmode);
/* Lock an XID (used to wait for a transaction to finish) */
extern void XactLockTableInsert(TransactionId xid);
extern void XactLockTableDelete(TransactionId xid);
extern void XactLockTableWait(TransactionId xid);
extern void XactLockTableWait(TransactionId xid, Relation rel,
ItemPointer ctid, XLTW_Oper oper);
extern bool ConditionalXactLockTableWait(TransactionId xid);
/* Lock VXIDs, specified by conflicting locktags */

5
src/nls-global.mk
View File

@ -57,7 +57,10 @@ BACKEND_COMMON_GETTEXT_TRIGGERS = \
errmsg errmsg_plural:1,2 \
errdetail errdetail_log errdetail_plural:1,2 \
errhint \
errcontext
errcontext \
XactLockTableWait:4 \
MultiXactIdWait:6 \
ConditionalMultiXactIdWait:6
BACKEND_COMMON_GETTEXT_FLAGS = \
errmsg:1:c-format errmsg_plural:1:c-format errmsg_plural:2:c-format \
errdetail:1:c-format errdetail_log:1:c-format errdetail_plural:1:c-format errdetail_plural:2:c-format \