use AV worker items infrastructure for GIN pending list's cleanup

[Jaime Casanova]

Hi,

When AV worker items where introduced 4 years ago, i was suggested that
it could be used for other things like cleaning the pending list of GIN
index when it reaches gin_pending_list_limit instead of making user
visible operation pay the price.

That never happened though. So, here is a little patch for that.

Should I add an entry for this on next commitfest?

-- 
Jaime Casanova
Director de Servicios Profesionales
SystemGuards - Consultores de PostgreSQL

diff --git a/src/backend/access/gin/ginfast.c b/src/backend/access/gin/ginfast.c
index e0d9940946..305326119c 100644
--- a/src/backend/access/gin/ginfast.c
+++ b/src/backend/access/gin/ginfast.c
@@ -459,7 +459,17 @@ ginHeapTupleFastInsert(GinState *ginstate, GinTupleCollector *collector)
 	 * pending list not forcibly.
 	 */
 	if (needCleanup)
-		ginInsertCleanup(ginstate, false, true, false, NULL);
+	{
+		bool		recorded;
+
+		recorded = AutoVacuumRequestWork(AVW_GINCleanPendingList, 
+					RelationGetRelid(ginstate->index), InvalidBlockNumber);
+		if (!recorded)
+			ereport(LOG,
+					(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+					 errmsg("request for GIN clean pending list for index \"%s\" was not recorded",
+							RelationGetRelationName(ginstate->index))));
+	}
 }
 
 /*
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 23ef23c13e..ee981640e3 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2680,6 +2680,10 @@ perform_work_item(AutoVacuumWorkItem *workitem)
 									ObjectIdGetDatum(workitem->avw_relation),
 									Int64GetDatum((int64) workitem->avw_blockNumber));
 				break;
+			case AVW_GINCleanPendingList:
+				DirectFunctionCall1(gin_clean_pending_list,
+									ObjectIdGetDatum(workitem->avw_relation));
+				break;
 			default:
 				elog(WARNING, "unrecognized work item found: type %d",
 					 workitem->avw_type);
@@ -3291,6 +3295,10 @@ autovac_report_workitem(AutoVacuumWorkItem *workitem,
 			snprintf(activity, MAX_AUTOVAC_ACTIV_LEN,
 					 "autovacuum: BRIN summarize");
 			break;
+		case AVW_GINCleanPendingList:
+			snprintf(activity, MAX_AUTOVAC_ACTIV_LEN,
+					 "autovacuum: GIN pending list cleanup");
+			break;
 	}
 
 	/*
diff --git a/src/include/postmaster/autovacuum.h b/src/include/postmaster/autovacuum.h
index aacdd0f575..2cbdde41c4 100644
--- a/src/include/postmaster/autovacuum.h
+++ b/src/include/postmaster/autovacuum.h
@@ -22,7 +22,8 @@
  */
 typedef enum
 {
-	AVW_BRINSummarizeRange
+	AVW_BRINSummarizeRange,
+	AVW_GINCleanPendingList
 } AutoVacuumWorkItemType;