From 3ce4df22c2dfd8baa8bf0ef186af072364524a9c Mon Sep 17 00:00:00 2001
From: Teodor Sigaev <teodor@sigaev.ru>
Date: Wed, 10 May 2017 19:09:55 +0300
Subject: [PATCH] cleanup local hash  on drop table command

---
 online_analyze.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/online_analyze.c b/online_analyze.c
index 90755e2..9c7fe20 100644
--- a/online_analyze.c
+++ b/online_analyze.c
@@ -31,6 +31,7 @@
 
 #include "pgstat.h"
 #include "access/transam.h"
+#include "access/xact.h"
 #include "catalog/namespace.h"
 #include "commands/vacuum.h"
 #include "executor/executor.h"
@@ -752,6 +753,24 @@ onlineAnalyzeHooker(QueryDesc *queryDesc)
 		standard_ExecutorEnd(queryDesc);
 }
 
+static void
+removeTable(XactEvent event, void *arg)
+{
+	List		*toremove = arg;
+	ListCell	*cell;
+
+	if (event != XACT_EVENT_COMMIT)
+		return;
+
+	foreach(cell, toremove)
+	{
+		Oid	relOid = lfirst_oid(cell);
+
+		hash_search(relstats, &relOid, HASH_REMOVE, NULL);
+	}
+}
+
+
 #if PG_VERSION_NUM >= 90200
 static void
 onlineAnalyzeHookerUtility(
@@ -793,6 +812,31 @@ onlineAnalyzeHookerUtility(
 			tblnames = list_copy(((TruncateStmt*)parsetree)->relations);
 			op = CK_TRUNCATE;
 		}
+		else if (IsA(parsetree, DropStmt) &&
+				 ((DropStmt*)parsetree)->removeType == OBJECT_TABLE)
+		{
+			ListCell	*cell;
+			List		*toremove = NIL;
+
+			foreach(cell, ((DropStmt*)parsetree)->objects)
+			{
+				List		*relname = (List *) lfirst(cell);
+				RangeVar	*rel = makeRangeVarFromNameList(relname);
+				Oid			relOid = RangeVarGetRelid(rel, NoLock, true);
+
+				if (OidIsValid(relOid))
+				{
+					MemoryContext	ctx;
+
+					ctx = MemoryContextSwitchTo(TopTransactionContext);
+					toremove = lappend_oid(toremove, relOid);
+					MemoryContextSwitchTo(ctx);
+				}
+			}
+
+			if (list_length(toremove) > 0)
+				RegisterXactCallback(removeTable, toremove);
+		}
 		else if (IsA(parsetree, VacuumStmt))
 		{
 			VacuumStmt	*vac = (VacuumStmt*)parsetree;
-- 
2.46.1