Improve error messages and add comment

diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c
index 15acb18c80d9a83ce745bfca3f56ced6bfc05cde..49766a46080cf34ddf8837d527c476d7a41582a4 100644 (file)
--- a/src/backend/access/gist/gistxlog.c
+++ b/src/backend/access/gist/gistxlog.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *           $PostgreSQL: pgsql/src/backend/access/gist/gistxlog.c,v 1.6 2005/06/30 17:52:14 teodor Exp $
+ *           $PostgreSQL: pgsql/src/backend/access/gist/gistxlog.c,v 1.7 2005/07/01 13:18:17 teodor Exp $
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
@@ -162,7 +162,7 @@ gistRedoEntryUpdateRecord(XLogRecPtr lsn, XLogRecord *record, bool isnewroot) {
                return;
        buffer = XLogReadBuffer(false, reln, xlrec.data->blkno);
        if (!BufferIsValid(buffer))
-               elog(PANIC, "gistRedoEntryUpdateRecord: block unfound");
+               elog(PANIC, "gistRedoEntryUpdateRecord: block %u unfound", xlrec.data->blkno);
        page = (Page) BufferGetPage(buffer);
 
        if ( isnewroot ) {
@@ -173,7 +173,7 @@ gistRedoEntryUpdateRecord(XLogRecPtr lsn, XLogRecord *record, bool isnewroot) {
                }
        } else { 
                if ( PageIsNew((PageHeader) page) )
-                       elog(PANIC, "gistRedoEntryUpdateRecord: uninitialized page");
+                       elog(PANIC, "gistRedoEntryUpdateRecord: uninitialized page blkno %u", xlrec.data->blkno);
                if (XLByteLE(lsn, PageGetLSN(page))) {
                        LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
                        ReleaseBuffer(buffer);
@@ -476,7 +476,7 @@ gistXLogReadAndLockBuffer( Relation r, BlockNumber blkno ) {
        if (!BufferIsValid(buffer))
                elog(PANIC, "gistXLogReadAndLockBuffer: block %u unfound", blkno);
        if ( PageIsNew( (PageHeader)(BufferGetPage(buffer)) ) )
-               elog(PANIC, "gistXLogReadAndLockBuffer: uninitialized page %u", blkno);
+               elog(PANIC, "gistXLogReadAndLockBuffer: uninitialized page blkno %u", blkno);
        
        return buffer;
 }
@@ -510,6 +510,15 @@ gixtxlogFindPath( Relation index, gistIncompleteInsert *insert ) {
                elog(LOG, "gixtxlogFindPath: lost parent for block %u", insert->origblkno);
 }
 
+/*
+ * Continue insert after crash. In normal situation, there isn't any incomplete 
+ * inserts, but if it might be after crash, WAL may has not a record of completetion.
+ * 
+ * Although stored LSN in gistIncompleteInsert is a LSN of child page, 
+ * we can compare it with LSN of parent, because parent is always locked 
+ * while we change child page (look at gistmakedeal). So if parent's LSN is 
+ * lesser than stored lsn then changes in parent doesn't do yet.
+ */   
 static void
 gistContinueInsert(gistIncompleteInsert *insert) {
        IndexTuple   *itup;
@@ -574,7 +583,7 @@ gistContinueInsert(gistIncompleteInsert *insert) {
                                elog(PANIC, "gistContinueInsert: block %u unfound", insert->path[i]);
                        pages[numbuffer-1] = BufferGetPage( buffers[numbuffer-1] );
                        if ( PageIsNew((PageHeader)(pages[numbuffer-1])) )
-                               elog(PANIC, "gistContinueInsert: uninitialized page");
+                               elog(PANIC, "gistContinueInsert: uninitialized page blkno %u", insert->path[i]);
 
                        if (XLByteLE(insert->lsn, PageGetLSN(pages[numbuffer-1]))) {
                                LockBuffer(buffers[numbuffer-1], BUFFER_LOCK_UNLOCK);