mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-08-26 20:17:18 +02:00
Defer restoration of libraries in parallel workers.
Several users of extensions complained of crashes in parallel workers that turned out to be due to syscache access from their _PG_init() functions. Reorder the initialization of parallel workers so that libraries are restored after the caches are initialized, and inside a transaction. This was reported in bug #15350 and elsewhere. We don't consider it to be a bug: extensions shouldn't do that, because then they can't be used in shared_preload_libraries. However, it's a fairly obscure hazard and these extensions worked in practice before parallel query came along. So let's make it work. Later commits might add a warning message and eventually an error. Back-patch to 9.6, where parallel query landed. Author: Thomas Munro Reviewed-by: Amit Kapila Reported-by: Kieran McCusker, Jimmy Discussion: https://postgr.es/m/153512195228.1489.8545997741965926448%40wrigleys.postgresql.org
This commit is contained in:
parent
265ac02457
commit
de4fe83c7e
@ -1148,15 +1148,6 @@ ParallelWorkerMain(Datum main_arg)
|
||||
fps->parallel_master_pid))
|
||||
return;
|
||||
|
||||
/*
|
||||
* Load libraries that were loaded by original backend. We want to do
|
||||
* this before restoring GUCs, because the libraries might define custom
|
||||
* variables.
|
||||
*/
|
||||
libraryspace = shm_toc_lookup(toc, PARALLEL_KEY_LIBRARY);
|
||||
Assert(libraryspace != NULL);
|
||||
RestoreLibraryState(libraryspace);
|
||||
|
||||
/*
|
||||
* Identify the entry point to be called. In theory this could result in
|
||||
* loading an additional library, though most likely the entry point is in
|
||||
@ -1186,10 +1177,19 @@ ParallelWorkerMain(Datum main_arg)
|
||||
*/
|
||||
SetClientEncoding(GetDatabaseEncoding());
|
||||
|
||||
/*
|
||||
* Load libraries that were loaded by original backend. We want to do
|
||||
* this before restoring GUCs, because the libraries might define custom
|
||||
* variables.
|
||||
*/
|
||||
libraryspace = shm_toc_lookup(toc, PARALLEL_KEY_LIBRARY);
|
||||
Assert(libraryspace != NULL);
|
||||
StartTransactionCommand();
|
||||
RestoreLibraryState(libraryspace);
|
||||
|
||||
/* Restore GUC values from launching backend. */
|
||||
gucspace = shm_toc_lookup(toc, PARALLEL_KEY_GUC);
|
||||
Assert(gucspace != NULL);
|
||||
StartTransactionCommand();
|
||||
RestoreGUCState(gucspace);
|
||||
CommitTransactionCommand();
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user