Teach autovacuum how to determine whether a temp table belongs to a crashed

backend.  If so, send a LOG message to the postmaster log, and if the table
is beyond the vacuum-for-wraparound horizon, forcibly drop it.  Per recent
discussions.  Perhaps we ought to back-patch this, but it probably needs
to age a bit in HEAD first.

diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index 5bacb412a971b1c2230e83d7f4f0a39938263fc8..dfaea41cfe4846e213d564d14bf14e84b0c0ce2c 100644 (file)
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.106 2008/06/19 00:46:04 alvherre Exp $
+ *   $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.107 2008/07/01 02:09:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2209,6 +2209,32 @@ isOtherTempNamespace(Oid namespaceId)
    return isAnyTempNamespace(namespaceId);
 }
 
+/*
+ * GetTempNamespaceBackendId - if the given namespace is a temporary-table
+ * namespace (either my own, or another backend's), return the BackendId
+ * that owns it.  Temporary-toast-table namespaces are included, too.
+ * If it isn't a temp namespace, return -1.
+ */
+int
+GetTempNamespaceBackendId(Oid namespaceId)
+{
+   int         result;
+   char       *nspname;
+
+   /* See if the namespace name starts with "pg_temp_" or "pg_toast_temp_" */
+   nspname = get_namespace_name(namespaceId);
+   if (!nspname)
+       return -1;              /* no such namespace? */
+   if (strncmp(nspname, "pg_temp_", 8) == 0)
+       result = atoi(nspname + 8);
+   else if (strncmp(nspname, "pg_toast_temp_", 14) == 0)
+       result = atoi(nspname + 14);
+   else
+       result = -1;
+   pfree(nspname);
+   return result;
+}
+
 /*
  * GetTempToastNamespace - get the OID of my temporary-toast-table namespace,
  * which must already be assigned. (This is only used when creating a toast

diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 7ac0bae1c588975c93893fb703b16509d8a8d751..9ed34eed6f824e6012b3f77be9c7f0ae0cffe4cd 100644 (file)
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -55,7 +55,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.79 2008/06/05 15:47:32 alvherre Exp $
+ *   $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.80 2008/07/01 02:09:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -71,6 +71,7 @@
 #include "access/heapam.h"
 #include "access/transam.h"
 #include "access/xact.h"
+#include "catalog/dependency.h"
 #include "catalog/indexing.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_autovacuum.h"
@@ -90,7 +91,7 @@
 #include "storage/pmsignal.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
-#include "storage/sinval.h"
+#include "storage/sinvaladt.h"
 #include "tcop/tcopprot.h"
 #include "utils/flatfiles.h"
 #include "utils/fmgroids.h"
@@ -275,10 +276,6 @@ static void autovac_balance_cost(void);
 static void do_autovacuum(void);
 static void FreeWorkerInfo(int code, Datum arg);
 
-static void relation_check_autovac(Oid relid, Form_pg_class classForm,
-                   Form_pg_autovacuum avForm, PgStat_StatTabEntry *tabentry,
-                      List **table_oids, List **table_toast_list,
-                      List **toast_oids);
 static autovac_table *table_recheck_autovac(Oid relid);
 static void relation_needs_vacanalyze(Oid relid, Form_pg_autovacuum avForm,
                          Form_pg_class classForm,
@@ -1912,19 +1909,16 @@ do_autovacuum(void)
        PgStat_StatTabEntry *tabentry;
        HeapTuple   avTup;
        Oid         relid;
+       bool        dovacuum;
+       bool        doanalyze;
+       bool        wraparound;
+       int         backendID;
 
        /* Consider only regular and toast tables. */
        if (classForm->relkind != RELKIND_RELATION &&
            classForm->relkind != RELKIND_TOASTVALUE)
            continue;
 
-       /*
-        * Skip temp tables (i.e. those in temp namespaces).  We cannot safely
-        * process other backends' temp tables.
-        */
-       if (isAnyTempNamespace(classForm->relnamespace))
-           continue;
-
        relid = HeapTupleGetOid(tuple);
 
        /* Fetch the pg_autovacuum tuple for the relation, if any */
@@ -1936,8 +1930,76 @@ do_autovacuum(void)
        tabentry = get_pgstat_tabentry_relid(relid, classForm->relisshared,
                                             shared, dbentry);
 
-       relation_check_autovac(relid, classForm, avForm, tabentry,
-                              &table_oids, &table_toast_list, &toast_oids);
+       /* Check if it needs vacuum or analyze */
+       relation_needs_vacanalyze(relid, avForm, classForm, tabentry,
+                                 &dovacuum, &doanalyze, &wraparound);
+
+       /*
+        * Check if it is a temp table (presumably, of some other backend's).
+        * We cannot safely process other backends' temp tables.
+        */
+       backendID = GetTempNamespaceBackendId(classForm->relnamespace);
+
+       if (backendID > 0)
+       {
+           /* We just ignore it if the owning backend is still active */
+           if (backendID == MyBackendId || !BackendIdIsActive(backendID))
+           {
+               /*
+                * We found an orphan temp table (which was probably left
+                * behind by a crashed backend).  If it's so old as to need
+                * vacuum for wraparound, forcibly drop it.  Otherwise just
+                * log a complaint.
+                */
+               if (wraparound && classForm->relkind == RELKIND_RELATION)
+               {
+                   ObjectAddress object;
+
+                   ereport(LOG,
+                           (errmsg("autovacuum: dropping orphan temp table \"%s\".\"%s\" in database \"%s\"",
+                                   get_namespace_name(classForm->relnamespace),
+                                   NameStr(classForm->relname),
+                                   get_database_name(MyDatabaseId))));
+                   object.classId = RelationRelationId;
+                   object.objectId = relid;
+                   object.objectSubId = 0;
+                   performDeletion(&object, DROP_CASCADE);
+               }
+               else
+               {
+                   ereport(LOG,
+                           (errmsg("autovacuum: found orphan temp table \"%s\".\"%s\" in database \"%s\"",
+                                   get_namespace_name(classForm->relnamespace),
+                                   NameStr(classForm->relname),
+                                   get_database_name(MyDatabaseId))));
+               }
+           }
+       }
+       else if (classForm->relkind == RELKIND_RELATION)
+       {
+           /* Plain relations that need work are added to table_oids */
+           if (dovacuum || doanalyze)
+               table_oids = lappend_oid(table_oids, relid);
+           else if (OidIsValid(classForm->reltoastrelid))
+           {
+               /*
+                * If it doesn't appear to need vacuuming, but it has a toast
+                * table, remember the association to revisit below.
+                */
+               av_relation *rel = palloc(sizeof(av_relation));
+
+               rel->ar_relid = relid;
+               rel->ar_toastrelid = classForm->reltoastrelid;
+
+               table_toast_list = lappend(table_toast_list, rel);
+           }
+       }
+       else
+       {
+           /* TOAST relations that need vacuum are added to toast_oids */
+           if (dovacuum)
+               toast_oids = lappend_oid(toast_oids, relid);
+       }
 
        if (HeapTupleIsValid(avTup))
            heap_freetuple(avTup);
@@ -2231,56 +2293,6 @@ get_pgstat_tabentry_relid(Oid relid, bool isshared, PgStat_StatDBEntry *shared,
    return tabentry;
 }
 
-/*
- * relation_check_autovac
- *
- * For a given relation (either a plain table or TOAST table), check whether it
- * needs vacuum or analyze.
- *
- * Plain tables that need either are added to the table_list.  TOAST tables
- * that need vacuum are added to toast_list.  Plain tables that don't need
- * either but which have a TOAST table are added, as a struct, to
- * table_toast_list.  The latter is to allow appending the OIDs of the plain
- * tables whose TOAST table needs vacuuming into the plain tables list, which
- * allows us to substantially reduce the number of "rechecks" that we need to
- * do later on.
- */
-static void
-relation_check_autovac(Oid relid, Form_pg_class classForm,
-                   Form_pg_autovacuum avForm, PgStat_StatTabEntry *tabentry,
-                      List **table_oids, List **table_toast_list,
-                      List **toast_oids)
-{
-   bool        dovacuum;
-   bool        doanalyze;
-   bool        dummy;
-
-   relation_needs_vacanalyze(relid, avForm, classForm, tabentry,
-                             &dovacuum, &doanalyze, &dummy);
-
-   if (classForm->relkind == RELKIND_TOASTVALUE)
-   {
-       if (dovacuum)
-           *toast_oids = lappend_oid(*toast_oids, relid);
-   }
-   else
-   {
-       Assert(classForm->relkind == RELKIND_RELATION);
-
-       if (dovacuum || doanalyze)
-           *table_oids = lappend_oid(*table_oids, relid);
-       else if (OidIsValid(classForm->reltoastrelid))
-       {
-           av_relation *rel = palloc(sizeof(av_relation));
-
-           rel->ar_relid = relid;
-           rel->ar_toastrelid = classForm->reltoastrelid;
-
-           *table_toast_list = lappend(*table_toast_list, rel);
-       }
-   }
-}
-
 /*
  * table_recheck_autovac
  *

diff --git a/src/backend/storage/ipc/sinvaladt.c b/src/backend/storage/ipc/sinvaladt.c
index e414e4a507105aef95fdde4e830b915b60490aa9..8aa4ec836b5f1920ab4cbddca34f746b79bde1ff 100644 (file)
--- a/src/backend/storage/ipc/sinvaladt.c
+++ b/src/backend/storage/ipc/sinvaladt.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/storage/ipc/sinvaladt.c,v 1.72 2008/06/20 00:24:53 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/storage/ipc/sinvaladt.c,v 1.73 2008/07/01 02:09:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -357,6 +357,33 @@ CleanupInvalidationState(int status, Datum arg)
    LWLockRelease(SInvalWriteLock);
 }
 
+/*
+ * BackendIdIsActive
+ *     Test if the given backend ID is currently assigned to a process.
+ */
+bool
+BackendIdIsActive(int backendID)
+{
+   bool        result;
+   SISeg      *segP = shmInvalBuffer;
+
+   /* Need to lock out additions/removals of backends */
+   LWLockAcquire(SInvalWriteLock, LW_SHARED);
+
+   if (backendID > 0 && backendID <= segP->lastBackend)
+   {
+       ProcState  *stateP = &segP->procState[backendID - 1];
+
+       result = (stateP->procPid != 0);
+   }
+   else
+       result = false;
+
+   LWLockRelease(SInvalWriteLock);
+
+   return result;
+}
+
 /*
  * SIInsertDataEntries
  *     Add new invalidation message(s) to the buffer.

diff --git a/src/include/catalog/namespace.h b/src/include/catalog/namespace.h
index 7c9ad7c73591e74188c59db4493a0edfcde5c7c6..b161b7108b6452f2566c5a61cb7cbb6337bf4fa4 100644 (file)
--- a/src/include/catalog/namespace.h
+++ b/src/include/catalog/namespace.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/namespace.h,v 1.53 2008/01/01 19:45:56 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/namespace.h,v 1.54 2008/07/01 02:09:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -95,6 +95,7 @@ extern bool isTempToastNamespace(Oid namespaceId);
 extern bool isTempOrToastNamespace(Oid namespaceId);
 extern bool isAnyTempNamespace(Oid namespaceId);
 extern bool isOtherTempNamespace(Oid namespaceId);
+extern int GetTempNamespaceBackendId(Oid namespaceId);
 extern Oid GetTempToastNamespace(void);
 extern void ResetTempTableNamespace(void);
 

diff --git a/src/include/storage/sinvaladt.h b/src/include/storage/sinvaladt.h
index 1748f8821b42d64233eafd9c182af63ed4e35ba3..abf243601c7a57f7be73a00849106b1396d01f5b 100644 (file)
--- a/src/include/storage/sinvaladt.h
+++ b/src/include/storage/sinvaladt.h
@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/storage/sinvaladt.h,v 1.48 2008/06/19 21:32:56 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/sinvaladt.h,v 1.49 2008/07/01 02:09:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -30,6 +30,7 @@
 extern Size SInvalShmemSize(void);
 extern void CreateSharedInvalidationState(void);
 extern void SharedInvalBackendInit(void);
+extern bool BackendIdIsActive(int backendID);
 
 extern void SIInsertDataEntries(const SharedInvalidationMessage *data, int n);
 extern int SIGetDataEntries(SharedInvalidationMessage *data, int datasize);