Fix nbtree page split rmgr desc routine.

Include newitemoff in rmgr desc output for nbtree page split records.
In passing, correct an obsolete comment that claimed that newitemoff is
only logged for _L variant nbtree page split WAL records.

Both issues were oversights in commit 2c03216d831, which revamped the
WAL format.

Author: Peter Geoghegan
Backpatch: 9.5-, where the WAL format was revamped.

diff --git a/src/backend/access/rmgrdesc/nbtdesc.c b/src/backend/access/rmgrdesc/nbtdesc.c
index 80bd70a9751038c58e5f2f03067988b55c40f9a4..4d7d8e6aab1ea1cd40a969c0f7a8fd0837792174 100644 (file)
--- a/src/backend/access/rmgrdesc/nbtdesc.c
+++ b/src/backend/access/rmgrdesc/nbtdesc.c
@@ -40,8 +40,8 @@ btree_desc(StringInfo buf, XLogReaderState *record)
                        {
                                xl_btree_split *xlrec = (xl_btree_split *) rec;
 
-                               appendStringInfo(buf, "level %u, firstright %d",
-                                                                xlrec->level, xlrec->firstright);
+                               appendStringInfo(buf, "level %u, firstright %d, newitemoff %d",
+                                                                xlrec->level, xlrec->firstright, xlrec->newitemoff);
                                break;
                        }
                case XLOG_BTREE_VACUUM:

diff --git a/src/include/access/nbtxlog.h b/src/include/access/nbtxlog.h
index 819373031cdf262713377bda2fb1f55368138a76..d69c9e33bae8ef76f515d1643a7bcdc2a9fc940f 100644 (file)
--- a/src/include/access/nbtxlog.h
+++ b/src/include/access/nbtxlog.h
@@ -82,12 +82,12 @@ typedef struct xl_btree_insert
  *
  * Note: the four XLOG_BTREE_SPLIT xl_info codes all use this data record.
  * The _L and _R variants indicate whether the inserted tuple went into the
- * left or right split page (and thus, whether newitemoff and the new item
- * are stored or not).  The _HIGHKEY variants indicate that we've logged
- * explicitly left page high key value, otherwise redo should use right page
- * leftmost key as a left page high key.  _HIGHKEY is specified for internal
- * pages where right page leftmost key is suppressed, and for leaf pages
- * of covering indexes where high key have non-key attributes truncated.
+ * left or right split page (and thus, whether the new item is stored or not).
+ * The _HIGHKEY variants indicate that we've logged explicitly left page high
+ * key value, otherwise redo should use right page leftmost key as a left page
+ * high key.  _HIGHKEY is specified for internal pages where right page
+ * leftmost key is suppressed, and for leaf pages of covering indexes where
+ * high key have non-key attributes truncated.
  *
  * Backup Blk 0: original page / new left page
  *
@@ -109,7 +109,7 @@ typedef struct xl_btree_split
 {
        uint32          level;                  /* tree level of page being split */
        OffsetNumber firstright;        /* first item moved to right page */
-       OffsetNumber newitemoff;        /* new item's offset (if placed on left page) */
+       OffsetNumber newitemoff;        /* new item's offset (useful for _L variant) */
 } xl_btree_split;
 
 #define SizeOfBtreeSplit       (offsetof(xl_btree_split, newitemoff) + sizeof(OffsetNumber))