Prevent continuing disk-space bloat when profiling (with PROFILE_PID_DIR

enabled) and autovacuum is on.  Since there will be a steady stream of autovac
worker processes exiting and dropping gmon.out files, allowing them to make
separate subdirectories results in serious bloat; and it seems unlikely that
anyone will care about those profiles anyway.  Limit the damage by forcing all
autovac workers to dump in one subdirectory, PGDATA/gprof/avworker/.

Per report from J\9arg Beyer and subsequent discussion.

diff --git a/src/backend/storage/ipc/ipc.c b/src/backend/storage/ipc/ipc.c
index e2f398d2e4540a72872d0f848275e72166edec9e..8f32e36301c03b08e183a22fd991b17160b1c240 100644 (file)
--- a/src/backend/storage/ipc/ipc.c
+++ b/src/backend/storage/ipc/ipc.c
@@ -13,7 +13,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/storage/ipc/ipc.c,v 1.97 2007/07/25 19:58:56 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/storage/ipc/ipc.c,v 1.98 2007/11/04 17:55:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -24,6 +24,9 @@
 #include <sys/stat.h>
 
 #include "miscadmin.h"
+#ifdef PROFILE_PID_DIR
+#include "postmaster/autovacuum.h"
+#endif
 #include "storage/ipc.h"
 
 
@@ -126,6 +129,11 @@ proc_exit(int code)
                 *      $PGDATA/gprof/8845/gmon.out
                 *              ...
                 *
+                * To avoid undesirable disk space bloat, autovacuum workers are
+                * discriminated against: all their gmon.out files go into the same
+                * subdirectory.  Without this, an installation that is "just sitting
+                * there" nonetheless eats megabytes of disk space every few seconds.
+                *
                 * Note that we do this here instead of in an on_proc_exit() 
                 * callback because we want to ensure that this code executes
                 * last - we don't want to interfere with any other on_proc_exit()
@@ -133,7 +141,10 @@ proc_exit(int code)
                 */
                char gprofDirName[32];
 
-               snprintf(gprofDirName, 32, "gprof/%d", (int) getpid());
+               if (IsAutoVacuumWorkerProcess())
+                       snprintf(gprofDirName, 32, "gprof/avworker");
+               else
+                       snprintf(gprofDirName, 32, "gprof/%d", (int) getpid());
            
                mkdir("gprof", 0777);
                mkdir(gprofDirName, 0777);