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 Mon, 30 Dec 2019 06:09:05 +0300 (MSK)
Date: Mon, 30 Dec 2019 06:09:04 +0300
From: Alexander Turenko <alexander.turenko@tarantool.org>
Message-ID: <20191230030904.ajxcgod553i424e2@tkn_work_nb>
References: <c0f30b2e1e5fe6155c9812d1c7188941b6d2eab5.1577629010.git.imeevma@gmail.com>
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In-Reply-To: <c0f30b2e1e5fe6155c9812d1c7188941b6d2eab5.1577629010.git.imeevma@gmail.com>
Subject: Re: [Tarantool-patches] [PATCH v2 test-run 1/1] sql: add another
 way to change SQL default engine
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To: Mergen Imeev <imeevma@tarantool.org>
Cc: tarantool-patches@dev.tarantool.org

> >> diff --git a/lib/tarantool_server.py b/lib/tarantool_server.py
> >> index 6f71b5b..20a398e 100644
> >> --- a/lib/tarantool_server.py
> >> +++ b/lib/tarantool_server.py
> >> @@ -145,12 +145,19 @@ class LuaTest(Test):
> >>              return True
> >>  
> >>          engine = self.run_params['engine']
> >> -        command = "pragma sql_default_engine='{}'".format(engine)
> >> -        result = self.send_command(command, ts, 'sql')
> >> -        result = result.replace('\r\n', '\n')
> >> -        if result != '---\n- row_count: 0\n...\n':
> >> -            sys.stdout.write(result)
> >> -            return False
> >> +
> >> +        command_new = ("UPDATE \"_session_settings\" SET \"value\" = '{}' " + \
> >> +                       "WHERE \"name\" = 'sql_default_engine'").format(engine)
> >> +        result_new = self.send_command(command_new, ts, 'sql')
> >> +        result_new = result_new.replace('\r\n', '\n')
> >> +
> >> +        command_old = "pragma sql_default_engine='{}'".format(engine)
> >> +        result_old = self.send_command(command_old, ts, 'sql')
> >> +        result_old = result_old.replace('\r\n', '\n')
> >> +        if result_new != '---\n- row_count: 1\n...\n':
> >> +            if result_old != '---\n- row_count: 0\n...\n':
> >> +                sys.stdout.write(result_old)
> >> +                return False
> >
> > I would make it like so:
> >
> > 1. Send "pragma ...", await a result.
> >    - If succeeds, return True.
> >    - Otherwise proceed with the step 2.
> > 2. Send "UPDATE ...", await a result.
> >    - If succeeds, return True.
> >    - Otherwise return False.
> >
> Fixed.

Ouch, occasionally I misdirected you. Sorry. I intend to say that we
should send the new-style command first and only then (if it fails) send
old-style "pragma ..." command.

This way we'll optimize the case when the new tarantool is tested that
will be most often case after some time.

> > This way we'll save one extra hop on a fresh tarantool. Not so big
> > overhead for an action that is run once for a test, but we can overcome
> > it and pay nothing, so it looks worthful for me.