Fix possible page corruption by ALTER TABLE .. SET TABLESPACE.

If a zeroed page is present in the heap, ALTER TABLE .. SET TABLESPACE will
set the LSN and TLI while copying it, which is wrong, and heap_xlog_newpage()
will do the same thing during replay, so the corruption propagates to any
standby.  Note, however, that the bug can't be demonstrated unless archiving
is enabled, since in that case we skip WAL logging altogether, and the LSN/TLI
are not set.

Back-patch to 8.0; prior releases do not have tablespaces.

Analysis and patch by Jeff Davis.  Adjustments for back-branches and minor
wordsmithing by me.

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index d6a04122cfcba722806b646e1349f1047f7490b1..d631a95de68b537ffbc0ded6e238a4d8d8d59451 100644 (file)
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.222.2.3 2008/12/16 16:26:21 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.222.2.4 2010/07/29 16:15:18 rhaas Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -3393,8 +3393,16 @@ heap_xlog_newpage(XLogRecPtr lsn, XLogRecord *record)
    Assert(record->xl_len == SizeOfHeapNewpage + BLCKSZ);
    memcpy(page, (char *) xlrec + SizeOfHeapNewpage, BLCKSZ);
 
-   PageSetLSN(page, lsn);
-   PageSetTLI(page, ThisTimeLineID);
+   /*
+    * The page may be uninitialized. If so, we can't set the LSN
+    * and TLI because that would corrupt the page.
+    */
+   if (!PageIsNew(page))
+   {
+       PageSetLSN(page, lsn);
+       PageSetTLI(page, ThisTimeLineID);
+   }
+
    MarkBufferDirty(buffer);
    UnlockReleaseBuffer(buffer);
 }

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 01255dc6b1f59edd3f99162ac9f7b4e9a18943e6..ec9696e6bbe532f3a4101801baa67a258720ca36 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.206.2.9 2010/07/01 14:11:23 rhaas Exp $
+ *   $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.206.2.10 2010/07/29 16:15:18 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -6151,8 +6151,15 @@ copy_relation_data(Relation rel, SMgrRelation dst)
 
            recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_NEWPAGE, rdata);
 
-           PageSetLSN(page, recptr);
-           PageSetTLI(page, ThisTimeLineID);
+           /*
+            * The page may be uninitialized. If so, we can't set the LSN
+            * and TLI because that would corrupt the page.
+            */
+           if (!PageIsNew(page))
+           {
+               PageSetLSN(page, recptr);
+               PageSetTLI(page, ThisTimeLineID);
+           }
 
            END_CRIT_SECTION();
        }