Re: [Tarantool-patches] [PATCH 3/8] txn: add TXN_WAIT_ACK flag

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Thanks for the review!

>>       stailq_foreach_entry(stmt, &txn->stmts, next) {
>>           if (stmt->has_triggers) {
>>               txn_init_triggers(txn);
>>               rlist_splice(&txn->on_commit, &stmt->on_commit);
>>           }
>> +        is_sync = is_sync || stmt->space->def->opts.is_sync;
> 
> Seems like
> "... || (stmt->space != NULL && stmt->space->def->opts.is_sync);"
> can be moved here from "replication: make sync transactions wait quorum".
> 
> LGTM.

I don't think it is a good idea. At this commit stmt->space can't be
NULL. This becomes possible only after Sergey P. starts using txns
to write confirm and rollback entries, which don't relate to any
space.

However I changed this place - I moved is_sync calculation after
stmt->row == NULL check. So as a read from a sync space wouldn't
turn the transaction into a synchronous one:

====================
commit e29fd482e0954913b87776d0a83ba04ef14683d8
Author: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
Date:   Sun Jun 21 18:12:53 2020 +0200

    txn: don't do sync flag calculation for read statements
    
    [TO BE SQUASHED INTO THE PREVIOUS COMMIT]

diff --git a/src/box/txn.c b/src/box/txn.c
index b50e7c1f8..22591a365 100644
--- a/src/box/txn.c
+++ b/src/box/txn.c
@@ -502,12 +502,13 @@ txn_journal_entry_new(struct txn *txn)
 			txn_init_triggers(txn);
 			rlist_splice(&txn->on_commit, &stmt->on_commit);
 		}
-		is_sync = is_sync || stmt->space->def->opts.is_sync;
 
 		/* A read (e.g. select) request */
 		if (stmt->row == NULL)
 			continue;
 
+		is_sync = is_sync || stmt->space->def->opts.is_sync;
+
 		if (stmt->row->replica_id == 0)
 			*local_row++ = stmt->row;
 		else