Optimize CleanupTempFiles by having a boolean flag that keeps track of whether

alvherre · alvherre · commit 5817d861e9cf · 2008-09-19T04:57:10.000Z
there are FD_XACT_TEMPORARY files to clean up at transaction end.

Per performance profiling results on AWeber's huge systems.

Patch by me after an idea suggested by Simon Riggs.
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/file/fd.c,v 1.144 2008/03/10 20:06:27 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/file/fd.c,v 1.145 2008/09/19 04:57:10 alvherre Exp $
  *
  * NOTES:
  *
@@ -121,6 +121,12 @@ static int	max_safe_fds = 32;	/* default if not changed */
 #define FD_TEMPORARY		(1 << 0)	/* T = delete when closed */
 #define FD_XACT_TEMPORARY	(1 << 1)	/* T = delete at eoXact */
 
+/*
+ * Flag to tell whether it's worth scanning VfdCache looking for temp files to
+ * close
+ */
+static bool		have_xact_temporary_files = false;
+
 typedef struct vfd
 {
 	int			fd;				/* current FD, or VFD_CLOSED if none */
@@ -889,6 +895,9 @@ OpenTemporaryFile(bool interXact)
 	{
 		VfdCache[file].fdstate |= FD_XACT_TEMPORARY;
 		VfdCache[file].create_subid = GetCurrentSubTransactionId();
+
+		/* ensure cleanup happens at eoxact */
+		have_xact_temporary_files = true;
 	}
 
 	return file;
@@ -1608,7 +1617,7 @@ AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid,
 {
 	Index		i;
 
-	if (SizeVfdCache > 0)
+	if (have_xact_temporary_files)
 	{
 		Assert(FileIsNotOpen(0));		/* Make sure ring not corrupted */
 		for (i = 1; i < SizeVfdCache; i++)
@@ -1684,7 +1693,11 @@ CleanupTempFiles(bool isProcExit)
 {
 	Index		i;
 
-	if (SizeVfdCache > 0)
+	/*
+	 * Careful here: at proc_exit we need extra cleanup, not just
+	 * xact_temporary files.
+	 */
+	if (isProcExit || have_xact_temporary_files)
 	{
 		Assert(FileIsNotOpen(0));		/* Make sure ring not corrupted */
 		for (i = 1; i < SizeVfdCache; i++)
@@ -1702,6 +1715,8 @@ CleanupTempFiles(bool isProcExit)
 					FileClose(i);
 			}
 		}
+
+		have_xact_temporary_files = false;
 	}
 
 	while (numAllocatedDescs > 0)

Original file line number	Diff line number	Diff line change
`@@ -7,7 +7,7 @@`
`7`	`7`	`* Portions Copyright (c) 1994, Regents of the University of California`
`8`	`8`	`*`
`9`	`9`	`* IDENTIFICATION`
`10`		`- * $PostgreSQL: pgsql/src/backend/storage/file/fd.c,v 1.144 2008/03/10 20:06:27 tgl Exp $`
	`10`	`+ * $PostgreSQL: pgsql/src/backend/storage/file/fd.c,v 1.145 2008/09/19 04:57:10 alvherre Exp $`
`11`	`11`	`*`
`12`	`12`	`* NOTES:`
`13`	`13`	`*`
`@@ -121,6 +121,12 @@ static int max_safe_fds = 32; /* default if not changed */`
`121`	`121`	`#define FD_TEMPORARY (1 << 0) /* T = delete when closed */`
`122`	`122`	`#define FD_XACT_TEMPORARY (1 << 1) /* T = delete at eoXact */`
`123`	`123`
	`124`	`+/*`
	`125`	`+ * Flag to tell whether it's worth scanning VfdCache looking for temp files to`
	`126`	`+ * close`
	`127`	`+ */`
	`128`	`+static bool have_xact_temporary_files = false;`
	`129`	`+`
`124`	`130`	`typedef struct vfd`
`125`	`131`	`{`
`126`	`132`	`int fd; /* current FD, or VFD_CLOSED if none */`
`@@ -889,6 +895,9 @@ OpenTemporaryFile(bool interXact)`
`889`	`895`	`{`
`890`	`896`	`VfdCache[file].fdstate \|= FD_XACT_TEMPORARY;`
`891`	`897`	`VfdCache[file].create_subid = GetCurrentSubTransactionId();`
	`898`	`+`
	`899`	`+ /* ensure cleanup happens at eoxact */`
	`900`	`+ have_xact_temporary_files = true;`
`892`	`901`	`}`
`893`	`902`
`894`	`903`	`return file;`
`@@ -1608,7 +1617,7 @@ AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid,`
`1608`	`1617`	`{`
`1609`	`1618`	`Index i;`
`1610`	`1619`
`1611`		`- if (SizeVfdCache > 0)`
	`1620`	`+ if (have_xact_temporary_files)`
`1612`	`1621`	`{`
`1613`	`1622`	`Assert(FileIsNotOpen(0)); /* Make sure ring not corrupted */`
`1614`	`1623`	`for (i = 1; i < SizeVfdCache; i++)`
`@@ -1684,7 +1693,11 @@ CleanupTempFiles(bool isProcExit)`
`1684`	`1693`	`{`
`1685`	`1694`	`Index i;`
`1686`	`1695`
`1687`		`- if (SizeVfdCache > 0)`
	`1696`	`+ /*`
	`1697`	`+ * Careful here: at proc_exit we need extra cleanup, not just`
	`1698`	`+ * xact_temporary files.`
	`1699`	`+ */`
	`1700`	`+ if (isProcExit \|\| have_xact_temporary_files)`
`1688`	`1701`	`{`
`1689`	`1702`	`Assert(FileIsNotOpen(0)); /* Make sure ring not corrupted */`
`1690`	`1703`	`for (i = 1; i < SizeVfdCache; i++)`
`@@ -1702,6 +1715,8 @@ CleanupTempFiles(bool isProcExit)`
`1702`	`1715`	`FileClose(i);`
`1703`	`1716`	`}`
`1704`	`1717`	`}`
	`1718`	`+`
	`1719`	`+ have_xact_temporary_files = false;`
`1705`	`1720`	`}`
`1706`	`1721`
`1707`	`1722`	`while (numAllocatedDescs > 0)`