branches/innodb+: btr_cur_search_to_nth_level(): Treat BTR_DELETE in

the same way as BTR_INSERT and BTR_DELETE_MARK: only perform (buffer)
the operation when the page is not in the buffer pool.

BTR_INSERT, BTR_DELETE_MARK, BTR_DELETE: Make the documentation say that
these flags are ignored when the page is in the buffer pool.

enum row_search_result: Remove ROW_NOT_DELETED, which
BTR_CUR_DELETE_FAILED was mapped to.

enum btr_cur_method: Remove BTR_CUR_DELETE_FAILED.  The
btr_cur_search_to_nth_level() will no longer attempt to execute the
BTR_DELETE when the page is in the buffer pool.

row_search_index_entry(): Remove the mapping from
BTR_CUR_DELETE_FAILED to ROW_NOT_DELETED.  The caller will have to
attempt purge when the record is in the buffer pool.

row_purge_remove_sec_if_poss_leaf(): Attempt to purge the record if it
was found in the buffer pool.

This addresses Issue #466.
rb://268

btr/btr0cur.c

@@ -338,7 +338,8 @@ btr_cur_search_to_nth_level(
 				Inserts should always be made using
 				PAGE_CUR_LE to search the position! */
 	ulint		latch_mode, /*!< in: BTR_SEARCH_LEAF, ..., ORed with
-				BTR_INSERT and BTR_ESTIMATE;
+				at most one of BTR_INSERT, BTR_DELETE_MARK,
+				BTR_DELETE, or BTR_ESTIMATE;
 				cursor->left_block is used to store a pointer
 				to the left neighbor page, in the cases
 				BTR_SEARCH_PREV and BTR_MODIFY_PREV;
@@ -773,35 +774,6 @@ retry_page_get:
 		      || mode != PAGE_CUR_LE);
 		ut_ad(cursor->low_match != ULINT_UNDEFINED
 		      || mode != PAGE_CUR_LE);
-
-		/* If this was a delete operation, the leaf page was
-		in the buffer pool, and a matching record was found in
-		the leaf page, attempt to delete it.  If the deletion
-		fails, set the cursor flag accordingly. */
-		if (UNIV_UNLIKELY(btr_op == BTR_DELETE_OP)
-		    && low_match == dtuple_get_n_fields(tuple)
-		    && !page_cur_is_before_first(page_cursor)) {
-
-			/* Before attempting to purge a record, check
-			if it is safe to do so. */
-			if (!row_purge_poss_sec(cursor->purge_node,
-						index, tuple)) {
-
-				cursor->flag = BTR_CUR_DELETE_REF;
-			} else {
-				/* Only delete-marked records should
-				be purged. */
-				ut_ad(REC_INFO_DELETED_FLAG
-				      & rec_get_info_bits(
-					      btr_cur_get_rec(cursor),
-					      page_is_comp(page)));
-
-				if (!btr_cur_optimistic_delete(cursor, mtr)) {
-
-					cursor->flag = BTR_CUR_DELETE_FAILED;
-				}
-			}
-		}
 	}
 
 func_exit:

include/btr0btr.h

@@ -71,7 +71,8 @@ enum btr_latch_mode {
 /* BTR_INSERT, BTR_DELETE and BTR_DELETE_MARK are mutually exclusive. */
 
 /** If this is ORed to btr_latch_mode, it means that the search tuple
-will be inserted to the index, at the searched position */
+will be inserted to the index, at the searched position.
+When the record is not in the buffer pool, try to use the insert buffer. */
 #define BTR_INSERT		512
 
 /** This flag ORed to btr_latch_mode says that we do the search in query
@@ -84,11 +85,11 @@ the insert buffer to speed up inserts */
 #define BTR_IGNORE_SEC_UNIQUE	2048
 
 /** Try to delete mark the record at the searched position using the
-insert/delete buffer. */
+insert/delete buffer when the record is not in the buffer pool. */
 #define BTR_DELETE_MARK		4096
 
-/** Try to delete the record at the searched position using the insert/delete
-buffer. */
+/** Try to purge the record at the searched position using the insert/delete
+buffer when the record is not in the buffer pool. */
 #define BTR_DELETE		8192
 
 /**************************************************************//**

include/btr0cur.h

@@ -138,7 +138,8 @@ btr_cur_search_to_nth_level(
 				should always be made using PAGE_CUR_LE to
 				search the position! */
 	ulint		latch_mode, /*!< in: BTR_SEARCH_LEAF, ..., ORed with
-				BTR_INSERT and BTR_ESTIMATE;
+				at most one of BTR_INSERT, BTR_DELETE_MARK,
+				BTR_DELETE, or BTR_ESTIMATE;
 				cursor->left_block is used to store a pointer
 				to the left neighbor page, in the cases
 				BTR_SEARCH_PREV and BTR_MODIFY_PREV;
@@ -634,9 +635,7 @@ enum btr_cur_method {
 				mark in the insert/delete buffer */
 	BTR_CUR_DELETE_IBUF,	/*!< performed the intended delete in
 				the insert/delete buffer */
-	BTR_CUR_DELETE_REF,	/*!< row_purge_poss_sec() failed */
-	BTR_CUR_DELETE_FAILED	/*!< an optimistic delete could not be
-				performed */
+	BTR_CUR_DELETE_REF	/*!< row_purge_poss_sec() failed */
 };
 
 /** The tree cursor: the definition appears here only for the compiler

include/row0row.h

@@ -269,8 +269,6 @@ enum row_search_result {
 				enqueued in the insert/delete buffer */
 	ROW_NOT_DELETED_REF,	/*!< BTR_DELETE was specified, and
 				row_purge_poss_sec() failed */
-	ROW_NOT_DELETED,	/*!< BTR_DELETE was specified, and the
-				optimistic delete failed */
 };
 
 /***************************************************************//**

row/row0purge.c

@@ -297,7 +297,6 @@ row_purge_remove_sec_if_poss_tree(
 		break;
 	case ROW_BUFFERED:
 	case ROW_NOT_DELETED_REF:
-	case ROW_NOT_DELETED:
 		/* These are invalid outcomes, because the mode passed
 		to row_search_index_entry() did not include any of the
 		flags BTR_INSERT, BTR_DELETE, or BTR_DELETE_MARK. */
@@ -366,24 +365,40 @@ row_purge_remove_sec_if_poss_leaf(
 	search_result = row_search_index_entry(
 		index, entry, BTR_MODIFY_LEAF | BTR_DELETE, &pcur, &mtr);
 
-	btr_pcur_close(&pcur);
-	mtr_commit(&mtr);
-
 	switch (search_result) {
-	case ROW_NOT_DELETED:
-		/* The index entry could not be deleted. */
-		return(FALSE);
+		ibool	success;
+	case ROW_FOUND:
+		/* Before attempting to purge a record, check
+		if it is safe to do so. */
+		if (row_purge_poss_sec(node, index, entry)) {
+			btr_cur_t* btr_cur = btr_pcur_get_btr_cur(&pcur);
+
+			/* Only delete-marked records should be purged. */
+			ut_ad(REC_INFO_DELETED_FLAG
+			      & rec_get_info_bits(
+				      btr_cur_get_rec(btr_cur),
+				      dict_table_is_comp(index->table)));
 
+			if (!btr_cur_optimistic_delete(btr_cur, &mtr)) {
+
+				/* The index entry could not be deleted. */
+				success = FALSE;
+				goto func_exit;
+			}
+		}
+		/* fall through (the index entry is still needed,
+		or the deletion succeeded) */
 	case ROW_NOT_DELETED_REF:
 		/* The index entry is still needed. */
-	case ROW_NOT_FOUND:
-		/* The index entry does not exist, nothing to do. */
-	case ROW_FOUND:
-		/* The index entry existed in the buffer pool
-		and was deleted because of the BTR_DELETE. */
 	case ROW_BUFFERED:
 		/* The deletion was buffered. */
-		return(TRUE);
+	case ROW_NOT_FOUND:
+		/* The index entry does not exist, nothing to do. */
+		success = TRUE;
+	func_exit:
+		btr_pcur_close(&pcur);
+		mtr_commit(&mtr);
+		return(success);
 	}
 
 	ut_error;

row/row0row.c

@@ -755,10 +755,6 @@ row_search_index_entry(
 		ut_a(mode & BTR_DELETE);
 		return(ROW_NOT_DELETED_REF);
 
-	case BTR_CUR_DELETE_FAILED:
-		ut_a(mode & BTR_DELETE);
-		return(ROW_NOT_DELETED);
-
 	case BTR_CUR_DEL_MARK_IBUF:
 	case BTR_CUR_DELETE_IBUF:
 	case BTR_CUR_INSERT_TO_IBUF:

row/row0uins.c

@@ -168,7 +168,6 @@ row_undo_ins_remove_sec_low(
 	case ROW_FOUND:
 		break;
 	case ROW_BUFFERED:
-	case ROW_NOT_DELETED:
 	case ROW_NOT_DELETED_REF:
 		/* These are invalid outcomes, because the mode passed
 		to row_search_index_entry() did not include any of the

row/row0umod.c

@@ -350,7 +350,6 @@ row_undo_mod_del_mark_or_remove_sec_low(
 	case ROW_FOUND:
 		break;
 	case ROW_BUFFERED:
-	case ROW_NOT_DELETED:
 	case ROW_NOT_DELETED_REF:
 		/* These are invalid outcomes, because the mode passed
 		to row_search_index_entry() did not include any of the
@@ -487,7 +486,6 @@ row_undo_mod_del_unmark_sec_and_undo_update(
 
 	switch (search_result) {
 	case ROW_BUFFERED:
-	case ROW_NOT_DELETED:
 	case ROW_NOT_DELETED_REF:
 		/* These are invalid outcomes, because the mode passed
 		to row_search_index_entry() did not include any of the

row/row0upd.c

@@ -1476,7 +1476,6 @@ row_upd_sec_index_entry(
 	rec = btr_cur_get_rec(btr_cur);
 
 	switch (search_result) {
-	case ROW_NOT_DELETED:		/* should only occur for BTR_DELETE */
 	case ROW_NOT_DELETED_REF:	/* should only occur for BTR_DELETE */
 		ut_error;
 		break;