Several bugfixes here:

1. don't enable statement timeout in parallel worker and 2. minor DSM cache fix. 3. don't clear learn_cache in a parallel worker.

Author: danolivo

aqo_shared.c

@@ -77,12 +77,10 @@ reset_dsm_cache(void)
 
 Assert(LWLockHeldByMeInMode(&aqo_state->lock, LW_EXCLUSIVE));
 
-if (aqo_state->dsm_handler == DSM_HANDLE_INVALID)
+if (aqo_state->dsm_handler == DSM_HANDLE_INVALID || !seg)
 /* Fast path. No any cached data exists. */
 return;
 
-Assert(seg);
-
 hdr = (dsm_seg_hdr *) dsm_segment_address(seg);
 start = (char *) hdr + sizeof(dsm_seg_hdr);
 

learn_cache.c

@@ -13,6 +13,7 @@
 */
 
 #include "postgres.h"
+#include "access/parallel.h" /* Just for IsParallelWorker() */
 #include "miscadmin.h"
 
 #include "aqo.h"
@@ -316,20 +317,25 @@ lc_assign_hook(bool newval, void *extra)
 HASH_SEQ_STATUS status;
 htab_entry *entry;
 
-if (!fss_htab || !IsUnderPostmaster)
+if (!fss_htab || !IsUnderPostmaster || IsParallelWorker())
+/* Clean this shared cache only in main backend process. */
 return;
 
 /* Remove all entries, reset memory context. */
 
 elog(DEBUG5, "[AQO] Cleanup local cache of ML data.");
 
-/* Remove all frozen plans from a plancache. */
+/* Remove all entries in the shared hash table. */
 LWLockAcquire(&aqo_state->lock, LW_EXCLUSIVE);
 hash_seq_init(&status, fss_htab);
 while ((entry = (htab_entry *) hash_seq_search(&status)) != NULL)
 {
 if (!hash_search(fss_htab, (void *) &entry->key, HASH_REMOVE, NULL))
 elog(PANIC, "[AQO] The local ML cache is corrupted.");
 }
+
+/* Now, clean additional DSM block */
+reset_dsm_cache();
+
 LWLockRelease(&aqo_state->lock);
 }