branches/zip: Note that it is legitimate for a secondary index record not

to be found during purge.  This tries to address Issue #129.  The comments
were supplied by Heikki.

include/row0uins.h

@@ -20,7 +20,9 @@ Created 2/25/1997 Heikki Tuuri
 /***************************************************************
 Undoes a fresh insert of a row to a table. A fresh insert means that
 the same clustered index unique key did not have any record, even delete
-marked, at the time of the insert. */
+marked, at the time of the insert.  InnoDB is eager in a rollback:
+if it figures out that an index record will be removed in the purge
+anyway, it will remove it in the rollback. */
 UNIV_INTERN
 ulint
 row_undo_ins(

row/row0purge.c

@@ -225,7 +225,15 @@ row_purge_remove_sec_if_poss_low(
 	found = row_search_index_entry(index, entry, mode, &pcur, &mtr);
 
 	if (!found) {
-		/* Not found */
+		/* Not found.  This is a legitimate condition.  In a
+		rollback, InnoDB will remove secondary recs that would
+		be purged anyway.  Then the actual purge will not find
+		the secondary index record.  Also, the purge itself is
+		eager: if it comes to consider a secondary index
+		record, and notices it does not need to exist in the
+		index, it will remove it.  Then if/when the purge
+		comes to consider the secondary index record a second
+		time, it will not exist any more in the index. */
 
 		/* fputs("PURGE:........sec entry not found\n", stderr); */
 		/* dtuple_print(stderr, entry); */

row/row0uins.c

@@ -274,7 +274,9 @@ row_undo_ins_parse_undo_rec(
 /***************************************************************
 Undoes a fresh insert of a row to a table. A fresh insert means that
 the same clustered index unique key did not have any record, even delete
-marked, at the time of the insert. */
+marked, at the time of the insert.  InnoDB is eager in a rollback:
+if it figures out that an index record will be removed in the purge
+anyway, it will remove it in the rollback. */
 UNIV_INTERN
 ulint
 row_undo_ins(