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postgres_fdw: Rephrase comment.

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Per gripe from Thomas Munro, who only complained about a more
localized problem, but I couldn't resist a bit more wordsmithing.
This commit is contained in:
Robert Haas 2016-06-17 13:01:14 -04:00
parent 9c188a8454
commit 177c56d608
1 changed files with 8 additions and 9 deletions
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17
contrib/postgres_fdw/postgres_fdw.c
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@ -4264,16 +4264,15 @@ postgresGetForeignJoinPaths(PlannerInfo *root,
fpinfo->attrs_used = NULL;
/*
* In case there is a possibility that EvalPlanQual will be executed, we
* should be able to reconstruct the row, from base relations applying all
* the conditions. We create a local plan from a suitable local path
* available in the path list. In case such a path doesn't exist, we can
* not push the join to the foreign server since we won't be able to
* If there is a possibility that EvalPlanQual will be executed, we need
* to be able to reconstruct the row using scans of the base relations.
* GetExistingLocalJoinPath will find a suitable path for this purpose in
* the path list of the joinrel, if one exists. We must be careful to
* call it before adding any ForeignPath, since the ForeignPath might
* dominate the only suitable local path available. We also do it before
* reconstruct the row for EvalPlanQual(). Find an alternative local path
* before we add ForeignPath, lest the new path would kick possibly the
* only local path. Do this before calling foreign_join_ok(), since that
* function updates fpinfo and marks it as pushable if the join is found
* to be pushable.
* calling foreign_join_ok(), since that function updates fpinfo and marks
* it as pushable if the join is found to be pushable.
*/
if (root->parse->commandType == CMD_DELETE ||
root->parse->commandType == CMD_UPDATE ||