20130711_1_index_conc_struct.patch

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 2a37cf2..db5917b 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1091,6 +1091,100 @@ index_create(Relation heapRelation,
 }
 
 /*
+ * index_concurrent_build
+ *
+ * Build index for a concurrent operation. Low-level locks are taken when this
+ * operation is performed to prevent only schema changes.
+ */
+void
+index_concurrent_build(Oid heapOid,
+					   Oid indexOid,
+					   bool isprimary)
+{
+	Relation	rel, indexRelation;
+	IndexInfo  *indexInfo;
+
+	/* Open and lock the parent heap relation */
+	rel = heap_open(heapOid, ShareUpdateExclusiveLock);
+
+	/* And the target index relation */
+	indexRelation = index_open(indexOid, RowExclusiveLock);
+
+	/*
+	 * We have to re-build the IndexInfo struct, since it was lost in
+	 * commit of transaction where this concurrent index was created
+	 * at the catalog level.
+	 */
+	indexInfo = BuildIndexInfo(indexRelation);
+	Assert(!indexInfo->ii_ReadyForInserts);
+	indexInfo->ii_Concurrent = true;
+	indexInfo->ii_BrokenHotChain = false;
+
+	/* Now build the index */
+	index_build(rel, indexRelation, indexInfo, isprimary, false);
+
+	/* Close both the relations, but keep the locks */
+	heap_close(rel, NoLock);
+	index_close(indexRelation, NoLock);
+}
+
+/*
+ * index_concurrent_set_dead
+ *
+ * Perform the last invalidation stage of DROP INDEX CONCURRENTLY before
+ * actually dropping the index. After calling this function the index is
+ * seen by all the backends as dead.
+ */
+void
+index_concurrent_set_dead(Oid heapOid, Oid indexOid, LOCKTAG locktag)
+{
+	Relation	heapRelation, indexRelation;
+
+	/*
+	 * Now we must wait until no running transaction could be using the
+	 * index for a query if necessary.
+	 *
+	 * Note: the reason we use actual lock acquisition here, rather than
+	 * just checking the ProcArray and sleeping, is that deadlock is
+	 * possible if one of the transactions in question is blocked trying
+	 * to acquire an exclusive lock on our table. The lock code will
+	 * detect deadlock and error out properly.
+	 */
+	WaitForVirtualLocks(locktag, AccessExclusiveLock);
+
+	/*
+	 * No more predicate locks will be acquired on this index, and we're
+	 * about to stop doing inserts into the index which could show
+	 * conflicts with existing predicate locks, so now is the time to move
+	 * them to the heap relation.
+	 */
+	heapRelation = heap_open(heapOid, ShareUpdateExclusiveLock);
+	indexRelation = index_open(indexOid, ShareUpdateExclusiveLock);
+	TransferPredicateLocksToHeapRelation(indexRelation);
+
+	/*
+	 * Now we are sure that nobody uses the index for queries; they just
+	 * might have it open for updating it.  So now we can unset indisready
+	 * and indislive, then wait till nobody could be using it at all
+	 * anymore.
+	 */
+	index_set_state_flags(indexOid, INDEX_DROP_SET_DEAD);
+
+	/*
+	 * Invalidate the relcache for the table, so that after this commit
+	 * all sessions will refresh the table's index list.  Forgetting just
+	 * the index's relcache entry is not enough.
+	 */
+	CacheInvalidateRelcache(heapRelation);
+
+	/*
+	 * Close the relations again, though still holding session lock.
+	 */
+	heap_close(heapRelation, NoLock);
+	index_close(indexRelation, NoLock);
+}
+
+/*
  * index_constraint_create
  *
  * Set up a constraint associated with an index
@@ -1444,50 +1538,8 @@ index_drop(Oid indexId, bool concurrent)
 		CommitTransactionCommand();
 		StartTransactionCommand();
 
-		/*
-		 * Now we must wait until no running transaction could be using the
-		 * index for a query. Note we do not need to worry about xacts that
-		 * open the table for reading after this point; they will see the
-		 * index as invalid when they open the relation.
-		 *
-		 * Note: the reason we use actual lock acquisition here, rather than
-		 * just checking the ProcArray and sleeping, is that deadlock is
-		 * possible if one of the transactions in question is blocked trying
-		 * to acquire an exclusive lock on our table.  The lock code will
-		 * detect deadlock and error out properly.
-		 */
-		WaitForVirtualLocks(heaplocktag, AccessExclusiveLock);
-
-		/*
-		 * No more predicate locks will be acquired on this index, and we're
-		 * about to stop doing inserts into the index which could show
-		 * conflicts with existing predicate locks, so now is the time to move
-		 * them to the heap relation.
-		 */
-		userHeapRelation = heap_open(heapId, ShareUpdateExclusiveLock);
-		userIndexRelation = index_open(indexId, ShareUpdateExclusiveLock);
-		TransferPredicateLocksToHeapRelation(userIndexRelation);
-
-		/*
-		 * Now we are sure that nobody uses the index for queries; they just
-		 * might have it open for updating it.	So now we can unset indisready
-		 * and indislive, then wait till nobody could be using it at all
-		 * anymore.
-		 */
-		index_set_state_flags(indexId, INDEX_DROP_SET_DEAD);
-
-		/*
-		 * Invalidate the relcache for the table, so that after this commit
-		 * all sessions will refresh the table's index list.  Forgetting just
-		 * the index's relcache entry is not enough.
-		 */
-		CacheInvalidateRelcache(userHeapRelation);
-
-		/*
-		 * Close the relations again, though still holding session lock.
-		 */
-		heap_close(userHeapRelation, NoLock);
-		index_close(userIndexRelation, NoLock);
+		/* Finish invalidation of index and mark it as dead */
+		index_concurrent_set_dead(heapId, indexId, heaplocktag);
 
 		/*
 		 * Again, commit the transaction to make the pg_index update visible
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index e913475..4ed9812 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -311,7 +311,6 @@ DefineIndex(IndexStmt *stmt,
 	Oid			tablespaceId;
 	List	   *indexColNames;
 	Relation	rel;
-	Relation	indexRelation;
 	HeapTuple	tuple;
 	Form_pg_am	accessMethodForm;
 	bool		amcanorder;
@@ -678,27 +677,13 @@ DefineIndex(IndexStmt *stmt,
 	 * HOT-chain or the extension of the chain is HOT-safe for this index.
 	 */
 
-	/* Open and lock the parent heap relation */
-	rel = heap_openrv(stmt->relation, ShareUpdateExclusiveLock);
-
-	/* And the target index relation */
-	indexRelation = index_open(indexRelationId, RowExclusiveLock);
-
 	/* Set ActiveSnapshot since functions in the indexes may need it */
 	PushActiveSnapshot(GetTransactionSnapshot());
 
-	/* We have to re-build the IndexInfo struct, since it was lost in commit */
-	indexInfo = BuildIndexInfo(indexRelation);
-	Assert(!indexInfo->ii_ReadyForInserts);
-	indexInfo->ii_Concurrent = true;
-	indexInfo->ii_BrokenHotChain = false;
-
-	/* Now build the index */
-	index_build(rel, indexRelation, indexInfo, stmt->primary, false);
-
-	/* Close both the relations, but keep the locks */
-	heap_close(rel, NoLock);
-	index_close(indexRelation, NoLock);
+	/* Perform concurrent build of index */
+	index_concurrent_build(RangeVarGetRelid(stmt->relation, NoLock, false),
+						   indexRelationId,
+						   stmt->primary);
 
 	/*
 	 * Update the pg_index row to mark the index as ready for inserts. Once we
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index e697275..9f29003 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -62,6 +62,14 @@ extern Oid index_create(Relation heapRelation,
 			 bool concurrent,
 			 bool is_internal);
 
+extern void index_concurrent_build(Oid heapOid,
+								   Oid indexOid,
+								   bool isprimary);
+
+extern void index_concurrent_set_dead(Oid heapOid,
+									  Oid indexOid,
+									  LOCKTAG locktag);
+
 extern void index_constraint_create(Relation heapRelation,
 						Oid indexRelationId,
 						IndexInfo *indexInfo,