diff options
Diffstat (limited to 'src/backend/optimizer/path/allpaths.c')
| -rw-r--r-- | src/backend/optimizer/path/allpaths.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c index bcb668fac5f..870a46ce74e 100644 --- a/src/backend/optimizer/path/allpaths.c +++ b/src/backend/optimizer/path/allpaths.c @@ -527,6 +527,23 @@ set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel, return; return; } + + /* + * Ask FDWs whether they can support performing a ForeignScan + * within a worker. Most often, the answer will be no. For + * example, if the nature of the FDW is such that it opens a TCP + * connection with a remote server, each parallel worker would end + * up with a separate connection, and these connections might not + * be appropriately coordinated between workers and the leader. + */ + if (rte->relkind == RELKIND_FOREIGN_TABLE) + { + Assert(rel->fdwroutine); + if (!rel->fdwroutine->IsForeignScanParallelSafe) + return; + if (!rel->fdwroutine->IsForeignScanParallelSafe(root, rel, rte)) + return; + } break; case RTE_SUBQUERY: |