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Make ExecGetInsertedCols() and friends more robust and improve comments.

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If ExecGetInsertedCols(), ExecGetUpdatedCols() or ExecGetExtraUpdatedCols()
were called with a ResultRelInfo that's not in the range table and isn't a
partition routing target, the functions would dereference a NULL pointer,
relinfo->ri_RootResultRelInfo. Such ResultRelInfos are created when firing
RI triggers in tables that are not modified directly. None of the current
callers of these functions pass such relations, so this isn't a live bug,
but let's make them more robust.

Also update comment in ResultRelInfo; after commit 6214e2b228,
ri_RangeTableIndex is zero for ResultRelInfos created for partition tuple
routing.

Noted by Coverity. Backpatch down to v11, like commit 6214e2b228.

Reviewed-by: Tom Lane, Amit Langote
This commit is contained in:
Heikki Linnakangas 2021-02-15 09:28:08 +02:00
parent a27f3a7f41
commit 2b81444a88
2 changed files with 30 additions and 13 deletions
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28
src/backend/executor/execUtils.c
View File

@ -1182,10 +1182,10 @@ Bitmapset *
ExecGetInsertedCols(ResultRelInfo *relinfo, EState *estate)
{
/*
* The columns are stored in the range table entry. If this ResultRelInfo
* doesn't have an entry in the range table (i.e. if it represents a
* partition routing target), fetch the parent's RTE and map the columns
* to the order they are in the partition.
* The columns are stored in the range table entry. If this ResultRelInfo
* represents a partition routing target, and doesn't have an entry of its
* own in the range table, fetch the parent's RTE and map the columns to
* the order they are in the partition.
*/
if (relinfo->ri_RangeTableIndex != 0)
{
@ -1193,7 +1193,7 @@ ExecGetInsertedCols(ResultRelInfo *relinfo, EState *estate)
return rte->insertedCols;
}
else
else if (relinfo->ri_RootResultRelInfo)
{
ResultRelInfo *rootRelInfo = relinfo->ri_RootResultRelInfo;
RangeTblEntry *rte = exec_rt_fetch(rootRelInfo->ri_RangeTableIndex, estate);
@ -1205,6 +1205,16 @@ ExecGetInsertedCols(ResultRelInfo *relinfo, EState *estate)
else
return rte->insertedCols;
}
else
{
/*
* The relation isn't in the range table and it isn't a partition
* routing target. This ResultRelInfo must've been created only for
* firing triggers and the relation is not being inserted into. (See
* ExecGetTriggerResultRel.)
*/
return NULL;
}
}
/* Return a bitmap representing columns being updated */
@ -1218,7 +1228,7 @@ ExecGetUpdatedCols(ResultRelInfo *relinfo, EState *estate)
return rte->updatedCols;
}
else
else if (relinfo->ri_RootResultRelInfo)
{
ResultRelInfo *rootRelInfo = relinfo->ri_RootResultRelInfo;
RangeTblEntry *rte = exec_rt_fetch(rootRelInfo->ri_RangeTableIndex, estate);
@ -1230,6 +1240,8 @@ ExecGetUpdatedCols(ResultRelInfo *relinfo, EState *estate)
else
return rte->updatedCols;
}
else
return NULL;
}
/* Return a bitmap representing generated columns being updated */
@ -1243,7 +1255,7 @@ ExecGetExtraUpdatedCols(ResultRelInfo *relinfo, EState *estate)
return rte->extraUpdatedCols;
}
else
else if (relinfo->ri_RootResultRelInfo)
{
ResultRelInfo *rootRelInfo = relinfo->ri_RootResultRelInfo;
RangeTblEntry *rte = exec_rt_fetch(rootRelInfo->ri_RangeTableIndex, estate);
@ -1255,6 +1267,8 @@ ExecGetExtraUpdatedCols(ResultRelInfo *relinfo, EState *estate)
else
return rte->extraUpdatedCols;
}
else
return NULL;
}
/* Return columns being updated, including generated columns */

15
src/include/nodes/execnodes.h
View File

@ -392,12 +392,15 @@ typedef struct OnConflictSetState
* relation, and perhaps also fire triggers. ResultRelInfo holds all the
* information needed about a result relation, including indexes.
*
* Normally, a ResultRelInfo refers to a table that is in the query's
* range table; then ri_RangeTableIndex is the RT index and ri_RelationDesc
* is just a copy of the relevant es_relations[] entry. But sometimes,
* in ResultRelInfos used only for triggers, ri_RangeTableIndex is zero
* and ri_RelationDesc is a separately-opened relcache pointer that needs
* to be separately closed. See ExecGetTriggerResultRel.
* Normally, a ResultRelInfo refers to a table that is in the query's range
* table; then ri_RangeTableIndex is the RT index and ri_RelationDesc is
* just a copy of the relevant es_relations[] entry. However, in some
* situations we create ResultRelInfos for relations that are not in the
* range table, namely for targets of tuple routing in a partitioned table,
* and when firing triggers in tables other than the target tables (See
* ExecGetTriggerResultRel). In these situations, ri_RangeTableIndex is 0
* and ri_RelationDesc is a separately-opened relcache pointer that needs to
* be separately closed.
*/
typedef struct ResultRelInfo
{