diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index eb25c2f4707..5da05283822 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -322,14 +322,11 @@ standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams) * functions are present in the query tree. * * (Note that we do allow CREATE TABLE AS, SELECT INTO, and CREATE - * MATERIALIZED VIEW to use parallel plans, but this is safe only because - * the command is writing into a completely new table which workers won't - * be able to see. If the workers could see the table, the fact that - * group locking would cause them to ignore the leader's heavyweight - * relation extension lock and GIN page locks would make this unsafe. - * We'll have to fix that somehow if we want to allow parallel inserts in - * general; updates and deletes have additional problems especially around - * combo CIDs.) + * MATERIALIZED VIEW to use parallel plans, but as of now, only the leader + * backend writes into a completely new table. In the future, we can + * extend it to allow workers to write into the table. However, to allow + * parallel updates and deletes, we have to solve other problems, + * especially around combo CIDs.) * * For now, we don't try to use parallel mode if we're running inside a * parallel worker. We might eventually be able to relax this |