Apply CORE-190, pg_buffercache patch

dmpgpro · dmpgpro · commit bdbee686be19 · 2016-10-24T11:43:49.000+03:00
diff --git a/contrib/pg_buffercache/Makefile b/contrib/pg_buffercache/Makefile
@@ -4,8 +4,9 @@ MODULE_big = pg_buffercache
 OBJS = pg_buffercache_pages.o $(WIN32RES)
 
 EXTENSION = pg_buffercache
-DATA = pg_buffercache--1.2.sql pg_buffercache--1.1--1.2.sql \
-	pg_buffercache--1.0--1.1.sql pg_buffercache--unpackaged--1.0.sql
+DATA = pg_buffercache--1.3.sql pg_buffercache--1.2--1.3.sql \
+	pg_buffercache--1.1--1.2.sql pg_buffercache--1.0--1.1.sql \
+	pg_buffercache--unpackaged--1.0.sql
 PGFILEDESC = "pg_buffercache - monitoring of shared buffer cache in real-time"
 
 ifdef USE_PGXS
diff --git a/contrib/pg_buffercache/pg_buffercache--1.2--1.3.sql b/contrib/pg_buffercache/pg_buffercache--1.2--1.3.sql
@@ -0,0 +1,6 @@
+/* contrib/pg_buffercache/pg_buffercache--1.2--1.3.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pg_buffercache(text) UPDATE TO '1.3'" to load this file. \quit
+
+ALTER FUNCTION pg_buffercache_pages() PARALLEL SAFE;
diff --git a/contrib/pg_buffercache/pg_buffercache--1.3.sql b/contrib/pg_buffercache/pg_buffercache--1.3.sql
@@ -1,4 +1,4 @@
-/* contrib/pg_buffercache/pg_buffercache--1.2.sql */
+/* contrib/pg_buffercache/pg_buffercache--1.3.sql */
 
 -- complain if script is sourced in psql, rather than via CREATE EXTENSION
 \echo Use "CREATE EXTENSION pg_buffercache" to load this file. \quit
@@ -18,4 +18,4 @@ CREATE VIEW pg_buffercache AS
 
 -- Don't want these to be available to public.
 REVOKE ALL ON FUNCTION pg_buffercache_pages() FROM PUBLIC;
-REVOKE ALL ON pg_buffercache FROM PUBLIC;
+REVOKE ALL ON pg_buffercache FROM PUBLIC;
diff --git a/contrib/pg_buffercache/pg_buffercache.control b/contrib/pg_buffercache/pg_buffercache.control
@@ -1,5 +1,5 @@
 # pg_buffercache extension
 comment = 'examine the shared buffer cache'
-default_version = '1.2'
+default_version = '1.3'
 module_pathname = '$libdir/pg_buffercache'
 relocatable = true
diff --git a/contrib/pg_buffercache/pg_buffercache_pages.c b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -135,15 +135,6 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 		/* Return to original context when allocating transient memory */
 		MemoryContextSwitchTo(oldcontext);
 
-		/*
-		 * To get a consistent picture of the buffer state, we must lock all
-		 * partitions of the buffer map.  Needless to say, this is horrible
-		 * for concurrency.  Must grab locks in increasing order to avoid
-		 * possible deadlocks.
-		 */
-		for (i = 0; i < NUM_BUFFER_PARTITIONS; i++)
-			LWLockAcquire(BufMappingPartitionLockByIndex(i), LW_SHARED);
-
 		/*
 		 * Scan through all the buffers, saving the relevant fields in the
 		 * fctx->record structure.
@@ -154,6 +145,12 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 			uint32		buf_state;
 
 			bufHdr = GetBufferDescriptor(i);
+			if (bufHdr->tag.forkNum == -1)
+			{
+				fctx->record[i].blocknum = InvalidBlockNumber;
+				continue;
+			}
+
 			/* Lock each buffer header before inspecting. */
 			buf_state = LockBufHdr(bufHdr);
 
@@ -179,16 +176,6 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 
 			UnlockBufHdr(bufHdr, buf_state);
 		}
-
-		/*
-		 * And release locks.  We do this in reverse order for two reasons:
-		 * (1) Anyone else who needs more than one of the locks will be trying
-		 * to lock them in increasing order; we don't want to release the
-		 * other process until it can get all the locks it needs. (2) This
-		 * avoids O(N^2) behavior inside LWLockRelease.
-		 */
-		for (i = NUM_BUFFER_PARTITIONS; --i >= 0;)
-			LWLockRelease(BufMappingPartitionLockByIndex(i));
 	}
 
 	funcctx = SRF_PERCALL_SETUP();
