[Tarantool-patches] [PATCH 07/16] tx: save preserve old tuple flag in txn_stmt

[Aleksandr Lyapunov <alyapunov@tarantool.org>]

---
 src/box/memtx_space.c | 17 +++++++++++++++++
 src/box/txn.c         |  3 +++
 src/box/txn.h         |  9 +++++++++
 3 files changed, 29 insertions(+)

diff --git a/src/box/memtx_space.c b/src/box/memtx_space.c
index 8755920..5820c40 100644
--- a/src/box/memtx_space.c
+++ b/src/box/memtx_space.c
@@ -316,6 +316,10 @@ memtx_space_execute_replace(struct space *space, struct txn *txn,
 	if (stmt->new_tuple == NULL)
 		return -1;
 	tuple_ref(stmt->new_tuple);
+
+	if (mode == DUP_INSERT)
+		stmt->preserve_old_tuple = true;
+
 	if (memtx_space->replace(space, NULL, stmt->new_tuple,
 				 mode, &stmt->old_tuple) != 0)
 		return -1;
@@ -342,6 +346,13 @@ memtx_space_execute_delete(struct space *space, struct txn *txn,
 	struct tuple *old_tuple;
 	if (index_get(pk, key, part_count, &old_tuple) != 0)
 		return -1;
+
+	/*
+	 * We have to delete exactly old_tuple just because we return it as
+	 * a result.
+	 */
+	stmt->preserve_old_tuple = true;
+
 	if (old_tuple != NULL &&
 	    memtx_space->replace(space, old_tuple, NULL,
 				 DUP_REPLACE_OR_INSERT, &stmt->old_tuple) != 0)
@@ -390,6 +401,9 @@ memtx_space_execute_update(struct space *space, struct txn *txn,
 	if (stmt->new_tuple == NULL)
 		return -1;
 	tuple_ref(stmt->new_tuple);
+
+	stmt->preserve_old_tuple = true;
+
 	if (memtx_space->replace(space, old_tuple, stmt->new_tuple,
 				 DUP_REPLACE, &stmt->old_tuple) != 0)
 		return -1;
@@ -496,6 +510,9 @@ memtx_space_execute_upsert(struct space *space, struct txn *txn,
 			stmt->new_tuple = NULL;
 		}
 	}
+
+	stmt->preserve_old_tuple = true;
+
 	/*
 	 * It's OK to use DUP_REPLACE_OR_INSERT: we don't risk
 	 * inserting a new tuple if the old one exists, since
diff --git a/src/box/txn.c b/src/box/txn.c
index b26613c..5fc34f8 100644
--- a/src/box/txn.c
+++ b/src/box/txn.c
@@ -108,6 +108,7 @@ txn_stmt_new(struct region *region)
 	stmt->engine_savepoint = NULL;
 	stmt->row = NULL;
 	stmt->has_triggers = false;
+	stmt->preserve_old_tuple = false;
 	return stmt;
 }
 
@@ -350,6 +351,8 @@ txn_commit_stmt(struct txn *txn, struct request *request)
 	 */
 	if (stmt->space != NULL && !rlist_empty(&stmt->space->on_replace) &&
 	    stmt->space->run_triggers && (stmt->old_tuple || stmt->new_tuple)) {
+		/* Triggers see old_tuple and that tuple must remain the same */
+		stmt->preserve_old_tuple = true;
 		int rc = 0;
 		if(!space_is_temporary(stmt->space)) {
 			rc = trigger_run(&stmt->space->on_replace, txn);
diff --git a/src/box/txn.h b/src/box/txn.h
index 1394bfb..e860e1e 100644
--- a/src/box/txn.h
+++ b/src/box/txn.h
@@ -129,6 +129,15 @@ struct txn_stmt {
 	struct xrow_header *row;
 	/** on_commit and/or on_rollback list is not empty. */
 	bool has_triggers;
+	/**
+	 * Whether the stmt upon commit must replace exactly old_tuple from it.
+	 * Explanation: to the moment of commit of the statement actual state
+	 * of the space could change due to commit of other transaction(s).
+	 * Some statements require the replaced tuple at the moment of commit to
+	 * be exactly the same as replaced tuple at the moment of execution.
+	 * Some - doesn't.
+	 */
+	bool preserve_old_tuple;
 	/** Commit/rollback triggers associated with this statement. */
 	struct rlist on_commit;
 	struct rlist on_rollback;
-- 
2.7.4