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Revise child-to-root tuple conversion map management.

Store the tuple conversion map to convert a tuple from a child table's
format to the root format in a new ri_ChildToRootMap field in
ResultRelInfo. It is initialized if transition tuple capture for FOR
STATEMENT triggers or INSERT tuple routing on a partitioned table is
needed. Previously, ModifyTable kept the maps in the per-subplan
ModifyTableState->mt_per_subplan_tupconv_maps array, or when tuple
routing was used, in
ResultRelInfo->ri_Partitioninfo->pi_PartitionToRootMap. The new field
replaces both of those.

Now that the child-to-root tuple conversion map is always available in
ResultRelInfo (when needed), remove the TransitionCaptureState.tcs_map
field. The callers of Exec*Trigger() functions no longer need to set or
save it, which is much less confusing and bug-prone. Also, as a future
optimization, this will allow us to delay creating the map for a given
result relation until the relation is actually processed during
execution.

Author: Amit Langote
Discussion: https://www.postgresql.org/message-id/CA%2BHiwqHtCWLdK-LO%3DNEsvOdHx%2B7yv4mE_zYK0i3BH7dXb-wxog%40mail.gmail.com
This commit is contained in:
Heikki Linnakangas
2020-10-19 14:11:54 +03:00
parent f49b85d783
commit 6973533650
8 changed files with 84 additions and 215 deletions

View File

@ -3106,31 +3106,14 @@ CopyFrom(CopyState cstate)
/*
* If we're capturing transition tuples, we might need to convert
* from the partition rowtype to root rowtype.
* from the partition rowtype to root rowtype. But if there are no
* BEFORE triggers on the partition that could change the tuple,
* we can just remember the original unconverted tuple to avoid a
* needless round trip conversion.
*/
if (cstate->transition_capture != NULL)
{
if (has_before_insert_row_trig)
{
/*
* If there are any BEFORE triggers on the partition,
* we'll have to be ready to convert their result back to
* tuplestore format.
*/
cstate->transition_capture->tcs_original_insert_tuple = NULL;
cstate->transition_capture->tcs_map =
resultRelInfo->ri_PartitionInfo->pi_PartitionToRootMap;
}
else
{
/*
* Otherwise, just remember the original unconverted
* tuple, to avoid a needless round trip conversion.
*/
cstate->transition_capture->tcs_original_insert_tuple = myslot;
cstate->transition_capture->tcs_map = NULL;
}
}
cstate->transition_capture->tcs_original_insert_tuple =
!has_before_insert_row_trig ? myslot : NULL;
/*
* We might need to convert from the root rowtype to the partition