Amit Langote <amitlangot...@gmail.com> writes:
> The crash reported here is in the other case where the concurrently
> added partitions cause the execution-time PartitionDesc to have more
> partitions than the one that PartitionedRelPruneInfo is based on.
> I was able to reproduce such a crash as follows:
Yeah, I can repeat the case per these directions. I concur that the
issue is that ExecCreatePartitionPruneState is failing to cope with
zeroes in the relid_map.
> The attached patch should fix that.
I don't like this patch at all though; I do not think it is being nearly
careful enough to ensure that it's matched the surviving relation OIDs
correctly. In particular it blithely assumes that a zero in relid_map
*must* match the immediately next entry in partdesc->oids, which is easy
to break if the new partition is adjacent to the one the planner managed
to prune. So I think we should do it more like the attached.
I'm strongly tempted to convert the trailing Assert to an actual
test-and-elog, too, but didn't do so here.
regards, tom lane
diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c
index fb6ce49056..221a34e738 100644
--- a/src/backend/executor/execPartition.c
+++ b/src/backend/executor/execPartition.c
@@ -1673,7 +1673,19 @@ ExecCreatePartitionPruneState(PlanState *planstate,
pprune->subpart_map = palloc(sizeof(int) * partdesc->nparts);
for (pp_idx = 0; pp_idx < partdesc->nparts; ++pp_idx)
{
- if (pinfo->relid_map[pd_idx] != partdesc->oids[pp_idx])
+ /*
+ * pinfo->relid_map can contain InvalidOid entries for
+ * partitions pruned by the planner. We cannot tell
+ * exactly which of the partdesc entries these correspond
+ * to, but we don't have to; just skip over them. The
+ * non-pruned relid_map entries, however, had better be a
+ * subset of the partdesc entries and in the same order.
+ */
+ while (pd_idx < pinfo->nparts &&
+ !OidIsValid(pinfo->relid_map[pd_idx]))
+ pd_idx++;
+ if (pd_idx >= pinfo->nparts ||
+ pinfo->relid_map[pd_idx] != partdesc->oids[pp_idx])
{
pprune->subplan_map[pp_idx] = -1;
pprune->subpart_map[pp_idx] = -1;
@@ -1686,6 +1698,14 @@ ExecCreatePartitionPruneState(PlanState *planstate,
pinfo->subpart_map[pd_idx++];
}
}
+
+ /*
+ * It might seem that we need to skip any trailing InvalidOid
+ * entries in pinfo->relid_map before asserting that we
+ * scanned all of the relid_map. But we will have skipped
+ * them above, because they must correspond to some
+ * partdesc->oids entries; we just couldn't tell which.
+ */
Assert(pd_idx == pinfo->nparts);
}
