rdelaage
/
postgresql
mirror of https://git.postgresql.org/git/postgresql.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Revert "Fix partition pruning setup during DETACH CONCURRENTLY" 

This reverts commit 27162a64b386; this branch is in code freeze due to a
nearing release.  We can commit again after the release is out.

Discussion: https://postgr.es/m/1158256.1719239648@sss.pgh.pa.us
This commit is contained in:
Alvaro Herrera 2024-06-24 17:20:21 +02:00
parent 27162a64b3
commit b0ea16528c
No known key found for this signature in database
GPG Key ID: 1C20ACB9D5C564AE
1 changed files with 50 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

110
src/backend/executor/execPartition.c
View File

@ -1942,31 +1942,37 @@ CreatePartitionPruneState(PlanState *planstate, PartitionPruneInfo *pruneinfo)
/*
* Initialize the subplan_map and subpart_map.
*
* The set of partitions that exist now might not be the same that
* existed when the plan was made. The normal case is that it is;
* optimize for that case with a quick comparison, and just copy
* the subplan_map and make subpart_map point to the one in
* PruneInfo.
* Because we request detached partitions to be included, and
* detaching waits for old transactions, it is safe to assume that
* no partitions have disappeared since this query was planned.
*
* For the case where they aren't identical, we could have more
* partitions on either side; or even exactly the same number of
* them on both but the set of OIDs doesn't match fully. Handle
* this by creating new subplan_map and subpart_map arrays that
* corresponds to the ones in the PruneInfo where the new
* partition descriptor's OIDs match. Any that don't match can be
* set to -1, as if they were pruned. Both arrays must be in
* numerical OID order.
* However, new partitions may have been added.
*/
Assert(partdesc->nparts >= pinfo->nparts);
pprune->nparts = partdesc->nparts;
pprune->subplan_map = palloc(sizeof(int) * partdesc->nparts);
if (partdesc->nparts == pinfo->nparts &&
memcmp(partdesc->oids, pinfo->relid_map,
sizeof(int) * partdesc->nparts) == 0)
if (partdesc->nparts == pinfo->nparts)
{
/*
* There are no new partitions, so this is simple. We can
* simply point to the subpart_map from the plan, but we must
* copy the subplan_map since we may change it later.
*/
pprune->subpart_map = pinfo->subpart_map;
memcpy(pprune->subplan_map, pinfo->subplan_map,
sizeof(int) * pinfo->nparts);
/*
* Double-check that the list of unpruned relations has not
* changed. (Pruned partitions are not in relid_map[].)
*/
#ifdef USE_ASSERT_CHECKING
for (int k = 0; k < pinfo->nparts; k++)
{
Assert(partdesc->oids[k] == pinfo->relid_map[k] ||
pinfo->subplan_map[k] == -1);
}
#endif
}
else
{
@ -1974,18 +1980,22 @@ CreatePartitionPruneState(PlanState *planstate, PartitionPruneInfo *pruneinfo)
int pp_idx;
/*
* When the partition arrays are not identical, there could be
* some new ones but it's also possible that one was removed;
* we cope with both situations by walking the arrays and
* discarding those that don't match.
* Some new partitions have appeared since plan time, and
* those are reflected in our PartitionDesc but were not
* present in the one used to construct subplan_map and
* subpart_map. So we must construct new and longer arrays
* where the partitions that were originally present map to
* the same sub-structures, and any added partitions map to
* -1, as if the new partitions had been pruned.
*
* If the number of partitions on both sides match, it's still
* possible that one partition has been detached and another
* attached. Cope with that by creating a map that skips any
* mismatches.
* Note: pinfo->relid_map[] may 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.
*/
pprune->subpart_map = palloc(sizeof(int) * partdesc->nparts);
for (pp_idx = 0; pp_idx < partdesc->nparts; pp_idx++)
{
/* Skip any InvalidOid relid_map entries */
@ -1993,7 +2003,6 @@ CreatePartitionPruneState(PlanState *planstate, PartitionPruneInfo *pruneinfo)
!OidIsValid(pinfo->relid_map[pd_idx]))
pd_idx++;
recheck:
if (pd_idx < pinfo->nparts &&
pinfo->relid_map[pd_idx] == partdesc->oids[pp_idx])
{
@ -2003,43 +2012,24 @@ CreatePartitionPruneState(PlanState *planstate, PartitionPruneInfo *pruneinfo)
pprune->subpart_map[pp_idx] =
pinfo->subpart_map[pd_idx];
pd_idx++;
continue;
}
/*
* There isn't an exact match in the corresponding
* positions of both arrays. Peek ahead in
* pinfo->relid_map to see if we have a match for the
* current partition in partdesc. Normally if a match
* exists it's just one element ahead, and it means the
* planner saw one extra partition that we no longer see
* now (its concurrent detach finished just in between);
* so we skip that one by updating pd_idx to the new
* location and jumping above. We can then continue to
* match the rest of the elements after skipping the OID
* with no match; no future matches are tried for the
* element that was skipped, because we know the arrays to
* be in the same order.
*
* If we don't see a match anywhere in the rest of the
* pinfo->relid_map array, that means we see an element
* now that the planner didn't see, so mark that one as
* pruned and move on.
*/
for (int pd_idx2 = pd_idx + 1; pd_idx2 < pinfo->nparts; pd_idx2++)
else
{
if (pd_idx2 >= pinfo->nparts)
break;
if (pinfo->relid_map[pd_idx2] == partdesc->oids[pp_idx])
{
pd_idx = pd_idx2;
goto recheck;
}
/* this partdesc entry is not in the plan */
pprune->subplan_map[pp_idx] = -1;
pprune->subpart_map[pp_idx] = -1;
}
pprune->subpart_map[pp_idx] = -1;
pprune->subplan_map[pp_idx] = -1;
}
/*
* It might seem that we need to skip any trailing InvalidOid
* entries in pinfo->relid_map before checking 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.
*/
if (pd_idx != pinfo->nparts)
elog(ERROR, "could not match partition child tables to plan elements");
}
/* present_parts is also subject to later modification */