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author | Robert Haas <rhaas@postgresql.org> | 2016-06-17 13:01:14 -0400 |
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committer | Robert Haas <rhaas@postgresql.org> | 2016-06-17 13:02:22 -0400 |
commit | 177c56d608d834ee1b0869e4e6a5b73de4227ea4 (patch) | |
tree | 0559984ba5f0aeeee525e6df1eefeec38a9c49bb /contrib/postgres_fdw/postgres_fdw.c | |
parent | 9c188a8454e514e43614e47d69f5eaea820af8c4 (diff) | |
download | postgresql-177c56d608d834ee1b0869e4e6a5b73de4227ea4.tar.gz postgresql-177c56d608d834ee1b0869e4e6a5b73de4227ea4.zip |
postgres_fdw: Rephrase comment.
Per gripe from Thomas Munro, who only complained about a more
localized problem, but I couldn't resist a bit more wordsmithing.
Diffstat (limited to 'contrib/postgres_fdw/postgres_fdw.c')
-rw-r--r-- | contrib/postgres_fdw/postgres_fdw.c | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c index 4b6ec14c65b..ccfad1b82a3 100644 --- a/contrib/postgres_fdw/postgres_fdw.c +++ b/contrib/postgres_fdw/postgres_fdw.c @@ -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 || |