database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-08 11:42:09 +03:00
Code Activity

Disallow COPY FREEZE on partitioned tables

Browse Source 
This didn't actually work: COPY would fail to flush the right files, and
instead would try to flush a non-existing file, causing the whole
transaction to fail.

Cope by raising an error as soon as the command is sent instead, to
avoid a nasty later surprise.  Of course, it would be much better to
make it work, but we don't have a patch for that yet, and we don't know
if we'll want to backpatch one when we do.

Reported-by: Tomas Vondra
Author: David Rowley
Reviewed-by: Amit Langote, Steve Singer, Tomas Vondra
This commit is contained in:
Alvaro Herrera
2018-11-19 11:16:28 -03:00
parent fc47e99a15
commit 5c9a5513a3
5 changed files with 44 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
src/backend/commands/copy.c
View File

@ -2416,11 +2416,20 @@ CopyFrom(CopyState cstate)
* go into pages containing tuples from any other transactions --- but this
* must be the case if we have a new table or new relfilenode, so we need
* no additional work to enforce that.
*
* We currently don't support this optimization if the COPY target is a
* partitioned table as we currently only lazily initialize partition
* information when routing the first tuple to the partition. We cannot
* know at this stage if we can perform this optimization. It should be
* possible to improve on this, but it does mean maintaining heap insert
* option flags per partition and setting them when we first open the
* partition.
*----------
*/
/* createSubid is creation check, newRelfilenodeSubid is truncation check */
if (cstate->rel->rd_createSubid != InvalidSubTransactionId ||
cstate->rel->rd_newRelfilenodeSubid != InvalidSubTransactionId)
if (cstate->rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE &&
(cstate->rel->rd_createSubid != InvalidSubTransactionId ||
cstate->rel->rd_newRelfilenodeSubid != InvalidSubTransactionId))
{
hi_options |= HEAP_INSERT_SKIP_FSM;
if (!XLogIsNeeded())
@ -2440,6 +2449,22 @@ CopyFrom(CopyState cstate)
*/
if (cstate->freeze)
{
/*
* We currently disallow COPY FREEZE on partitioned tables. The
* reason for this is that we've simply not yet opened the partitions
* to determine if the optimization can be applied to them. We could
* go and open them all here, but doing so may be quite a costly
* overhead for small copies. In any case, we may just end up routing
* tuples to a small number of partitions. It seems better just to
* raise an ERROR for partitioned tables.
*/
if (cstate->rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot perform FREEZE on a partitioned table")));
}
/*
* Tolerate one registration for the benefit of FirstXactSnapshot.
* Scan-bearing queries generally create at least two registrations,