Hi, On 02/01/14 10:02, Andres Freund wrote: > > Christian's idea of a context line seems plausible to me. I don't > > care for this implementation too much --- a global variable? Ick. > > Yea, the data should be stored in ErrorContextCallback.arg instead.
Fixed. I also palloc() the ErrorContextCallback itself. But it doesn't feel right since I could not find a piece of code doing so. What do you think? > > Make a wrapper function for XactLockTableWait instead, please. > > I don't think that'd work out all too nicely - we do the > XactLockTableWait() inside other functions like MultiXactIdWait(), > passing all the detail along for those would end up being ugly. So using > error context callbacks properly seems like the best way in the end. Wrapping XactLockTableWait()/MultiXactIdWait() at least allows the ErrorContextCallback and ErrorContextCallback.arg to live on the stack. So what we could do is wrap this in a macro instead of a function (like e.g. PG_TRY) or write two different functions. And I don't like the two functions approach since it means duplication of code. While writing the response I really think writing a macro in PG_TRY style for setting up and cleaning the error context callback I begin to think that this would be the best way to go. > > And I'm not real sure that showing the whole tuple contents is a good > > thing; I can see people calling that a security leak, not to mention > > that the performance consequences could be dire. > > I don't think that the security argument has too much merit given > today's PG - we already log the full tuple for various constraint > violations. And we also accept the performance penalty there. I don't > see any easy way to select a sensible subset of columns to print here, > and printing the columns is what would make investigating issues around > this so much easier. At the very least we'd need to print the pkey > columns and the columns of the unique key that might have been violated. I agree. Even printing only the PK values would be much more complex. As far as I can see we would even have to gain another lock for this (see comment for relationHasPrimaryKey() in src/backend/catalog/index.c). Regards, -- Christian Kruse http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index f8545c1..cfa49c2 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -2702,9 +2702,11 @@ l1:
if (infomask & HEAP_XMAX_IS_MULTI)
{
+ XactLockTableWaitSetupErrorContextCallback(relation, &tp);
/* wait for multixact */
MultiXactIdWait((MultiXactId) xwait, MultiXactStatusUpdate,
NULL, infomask);
+ XactLockTableWaitCleanupErrorContextCallback();
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
@@ -2730,7 +2732,10 @@ l1:
else
{
/* wait for regular transaction to end */
+ XactLockTableWaitSetupErrorContextCallback(relation, &tp);
+
XactLockTableWait(xwait);
+ XactLockTableWaitCleanupErrorContextCallback();
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
@@ -3254,9 +3259,11 @@ l2:
TransactionId update_xact;
int remain;
+ XactLockTableWaitSetupErrorContextCallback(relation, &oldtup);
/* wait for multixact */
MultiXactIdWait((MultiXactId) xwait, mxact_status, &remain,
infomask);
+ XactLockTableWaitCleanupErrorContextCallback();
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
@@ -3330,7 +3337,10 @@ l2:
else
{
/* wait for regular transaction to end */
+ XactLockTableWaitSetupErrorContextCallback(relation, &oldtup);
+
XactLockTableWait(xwait);
+ XactLockTableWaitCleanupErrorContextCallback();
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
/*
@@ -4398,7 +4408,11 @@ l3:
RelationGetRelationName(relation))));
}
else
+ {
+ XactLockTableWaitSetupErrorContextCallback(relation, tuple);
MultiXactIdWait((MultiXactId) xwait, status, NULL, infomask);
+ XactLockTableWaitCleanupErrorContextCallback();
+ }
/* if there are updates, follow the update chain */
if (follow_updates &&
@@ -4453,7 +4467,11 @@ l3:
RelationGetRelationName(relation))));
}
else
+ {
+ XactLockTableWaitSetupErrorContextCallback(relation, tuple);
XactLockTableWait(xwait);
+ XactLockTableWaitCleanupErrorContextCallback();
+ }
/* if there are updates, follow the update chain */
if (follow_updates &&
@@ -5139,9 +5157,14 @@ l4:
if (needwait)
{
+ XactLockTableWaitSetupErrorContextCallback(rel, &mytup);
+
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
XactLockTableWait(members[i].xid);
pfree(members);
+
+ XactLockTableWaitCleanupErrorContextCallback();
+
goto l4;
}
if (res != HeapTupleMayBeUpdated)
@@ -5199,8 +5222,13 @@ l4:
&needwait);
if (needwait)
{
+ XactLockTableWaitSetupErrorContextCallback(rel, &mytup);
+
LockBuffer(buf, BUFFER_LOCK_UNLOCK);
XactLockTableWait(rawxmax);
+
+ XactLockTableWaitCleanupErrorContextCallback();
+
goto l4;
}
if (res != HeapTupleMayBeUpdated)
diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c
index a452fea..7f79615 100644
--- a/src/backend/access/nbtree/nbtinsert.c
+++ b/src/backend/access/nbtree/nbtinsert.c
@@ -165,7 +165,11 @@ top:
{
/* Have to wait for the other guy ... */
_bt_relbuf(rel, buf);
+
+ XactLockTableWaitSetupErrorContextCallback(rel, NULL);
XactLockTableWait(xwait);
+ XactLockTableWaitCleanupErrorContextCallback();
+
/* start over... */
_bt_freestack(stack);
goto top;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 7ad9720..6e80e37 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -2297,7 +2297,11 @@ IndexBuildHeapScan(Relation heapRelation,
* Must drop the lock on the buffer before we wait
*/
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
+
+ XactLockTableWaitSetupErrorContextCallback(heapRelation, heapTuple);
XactLockTableWait(xwait);
+ XactLockTableWaitCleanupErrorContextCallback();
+
goto recheck;
}
}
@@ -2343,7 +2347,11 @@ IndexBuildHeapScan(Relation heapRelation,
* Must drop the lock on the buffer before we wait
*/
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
+
+ XactLockTableWaitSetupErrorContextCallback(heapRelation, heapTuple);
XactLockTableWait(xwait);
+ XactLockTableWaitCleanupErrorContextCallback();
+
goto recheck;
}
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 6be17a9..2ee6f51 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1981,7 +1981,11 @@ EvalPlanQualFetch(EState *estate, Relation relation, int lockmode,
if (TransactionIdIsValid(SnapshotDirty.xmax))
{
ReleaseBuffer(buffer);
+
+ XactLockTableWaitSetupErrorContextCallback(relation, &tuple);
XactLockTableWait(SnapshotDirty.xmax);
+ XactLockTableWaitCleanupErrorContextCallback();
+
continue; /* loop back to repeat heap_fetch */
}
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 39e3b2e..65aca6e 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -1307,7 +1307,11 @@ retry:
if (TransactionIdIsValid(xwait))
{
index_endscan(index_scan);
+
+ XactLockTableWaitSetupErrorContextCallback(heap, tup);
XactLockTableWait(xwait);
+ XactLockTableWaitCleanupErrorContextCallback();
+
goto retry;
}
diff --git a/src/backend/storage/lmgr/lmgr.c b/src/backend/storage/lmgr/lmgr.c
index a978172..f0b5140 100644
--- a/src/backend/storage/lmgr/lmgr.c
+++ b/src/backend/storage/lmgr/lmgr.c
@@ -18,12 +18,14 @@
#include "access/subtrans.h"
#include "access/transam.h"
#include "access/xact.h"
+#include "access/htup_details.h"
#include "catalog/catalog.h"
#include "miscadmin.h"
#include "storage/lmgr.h"
#include "storage/procarray.h"
#include "utils/inval.h"
-
+#include "utils/lsyscache.h"
+#include "mb/pg_wchar.h"
/*
* RelationInitLockInfo
@@ -533,6 +535,148 @@ ConditionalXactLockTableWait(TransactionId xid)
return true;
}
+struct XactLockTableWaitLockInfo {
+ Relation rel;
+ HeapTuple tuple;
+};
+
+/*
+ * XactLockTableWaitErrorContextCallback
+ * error context callback set up by
+ * XactLockTableWaitSetupErrorContextCallback. It reports some
+ * tuple information and the relation of a lock to aquire
+ *
+ */
+static void
+XactLockTableWaitErrorContextCallback(void *arg)
+{
+ StringInfoData buf;
+ int i;
+ bool write_comma = false;
+ int maxfieldlen = 30;
+ struct XactLockTableWaitLockInfo *info = (struct XactLockTableWaitLockInfo *)arg;
+
+ if (info->rel != NULL)
+ {
+ errcontext("relation name: %s (OID %u)",
+ RelationGetRelationName(info->rel),
+ RelationGetRelid(info->rel));
+ }
+
+ if (info->tuple != NULL)
+ {
+ /*
+ * Can't produce an error message including the tuple if we're in a
+ * possibly aborted transaction state, database access might not be safe.
+ */
+ if (geterrlevel() >= ERROR)
+ {
+ errcontext("tuple ctid (%u,%u)",
+ BlockIdGetBlockNumber(&(info->tuple->t_self.ip_blkid)),
+ info->tuple->t_self.ip_posid);
+ }
+ else
+ {
+ TupleDesc desc = RelationGetDescr(info->rel);
+ Datum *values = palloc(desc->natts * sizeof(*values));
+ bool *nulls = palloc(desc->natts * sizeof(*values));
+
+ heap_deform_tuple(info->tuple, desc, values, nulls);
+
+ initStringInfo(&buf);
+ appendStringInfoChar(&buf, '(');
+
+ for (i = 0; i < desc->natts; i++)
+ {
+ char *val;
+ int vallen;
+
+ if (nulls[i])
+ val = "null";
+ else
+ {
+ Oid foutoid;
+ bool typisvarlena;
+
+ getTypeOutputInfo(desc->attrs[i]->atttypid,
+ &foutoid, &typisvarlena);
+
+ val = OidOutputFunctionCall(foutoid, values[i]);
+ }
+
+ if (write_comma)
+ appendStringInfoString(&buf, ", ");
+ else
+ write_comma = true;
+
+ vallen = strlen(val);
+ if (vallen <= maxfieldlen)
+ appendStringInfoString(&buf, val);
+ else
+ {
+ vallen = pg_mbcliplen(val, vallen, maxfieldlen);
+ appendBinaryStringInfo(&buf, val, vallen);
+ appendStringInfoString(&buf, "...");
+ }
+ }
+
+ appendStringInfoChar(&buf, ')');
+
+ errcontext("tuple (ctid (%u,%u)): %s",
+ BlockIdGetBlockNumber(&(info->tuple->t_self.ip_blkid)),
+ info->tuple->t_self.ip_posid, buf.data);
+
+ pfree(buf.data);
+ pfree(values);
+ pfree(nulls);
+ }
+ }
+}
+
+/*
+ * XactLockTableWaitSetupErrorContextCallback
+ * Sets up the error context callback for reporting tuple
+ * information and relation for a lock to aquire
+ *
+ * Use this before calling XactTableLockWait() or MultiXactIdWait()
+ */
+void
+XactLockTableWaitSetupErrorContextCallback(Relation rel, HeapTuple tuple)
+{
+ struct XactLockTableWaitLockInfo *info = palloc(sizeof(*info));
+ ErrorContextCallback *callback = palloc(sizeof(*callback));
+
+ info->rel = rel;
+ info->tuple = tuple;
+
+ callback->callback = XactLockTableWaitErrorContextCallback;
+ callback->arg = info;
+ callback->previous = error_context_stack;
+ error_context_stack = callback;
+}
+
+/*
+ * XactLockTableWaitCleanupErrorContextCallback
+ * Removes the error callback context
+ *
+ * Use this after calling XactTableLockWait() or MultiXactIdWait()
+ */
+void
+XactLockTableWaitCleanupErrorContextCallback(void)
+{
+ ErrorContextCallback *callback = error_context_stack;
+
+ /*
+ * ensure that error context is set
+ */
+ Assert(callback->arg != NULL);
+
+ error_context_stack = callback->previous;
+
+ pfree(callback->arg);
+ pfree(callback);
+}
+
/*
* WaitForLockersMultiple
* Wait until no transaction holds locks that conflict with the given
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 65eb3bd..16e0410 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -1204,6 +1204,23 @@ geterrposition(void)
}
/*
+ * geterrlevel --- return the currently set error level
+ *
+ * This is only intended for use in error callback subroutines, since there
+ * is no other place outside elog.c where the concept is meaningful.
+ */
+int
+geterrlevel(void)
+{
+ ErrorData *edata = &errordata[errordata_stack_depth];
+
+ /* we don't bother incrementing recursion_depth */
+ CHECK_STACK_DEPTH();
+
+ return edata->elevel;
+}
+
+/*
* getinternalerrposition --- same for internal error position
*
* This is only intended for use in error callback subroutines, since there
diff --git a/src/include/storage/lmgr.h b/src/include/storage/lmgr.h
index 1a8c018..ff97888 100644
--- a/src/include/storage/lmgr.h
+++ b/src/include/storage/lmgr.h
@@ -18,6 +18,7 @@
#include "storage/itemptr.h"
#include "storage/lock.h"
#include "utils/rel.h"
+#include "access/htup.h"
extern void RelationInitLockInfo(Relation relation);
@@ -57,6 +58,9 @@ extern void XactLockTableDelete(TransactionId xid);
extern void XactLockTableWait(TransactionId xid);
extern bool ConditionalXactLockTableWait(TransactionId xid);
+extern void XactLockTableWaitSetupErrorContextCallback(Relation rel, HeapTuple tuple);
+extern void XactLockTableWaitCleanupErrorContextCallback(void);
+
/* Lock VXIDs, specified by conflicting locktags */
extern void WaitForLockers(LOCKTAG heaplocktag, LOCKMODE lockmode);
extern void WaitForLockersMultiple(List *locktags, LOCKMODE lockmode);
diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index 59d6f5e..71ebadc 100644
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -224,6 +224,7 @@ extern int err_generic_string(int field, const char *str);
extern int geterrcode(void);
extern int geterrposition(void);
+extern int geterrlevel(void);
extern int getinternalerrposition(void);
pgpdYe8fTkrQA.pgp
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