Re: bzr commit into mysql-5.1 branch (hezx:2632) Bug#37051

[Ingo Strüwing]

Hi Sven,

Sven Sandberg, 30.07.2008 17:38:
> 
> 
> Ingo Strüwing wrote:
...
>> Note that this is a difference against fixing the logic of
>> Query_log_event::write(). I still think that the latter is more risky.
> 
> How do you mean? I don't think we need to change the logic of
> Query_log_event::write() in any other way than replace the long
> computation by a macro that expands to the same computation. It just
> needs double-checking that the macro expands to the same thing as the
> original computation. It would me more risky to try to maintain two
> copies of the same computation, IMHO.
> 

In your first review you wrote: "Query_log_event::write() should use
MAX_LOG_EVENT_HEADER".

MAX_LOG_EVENT_HEADER contains LOG_EVENT_HEADER_LEN + QUERY_HEADER_LEN
  + EXECUTE_LOAD_QUERY_EXTRA_HEADER_LEN + MAX_SIZE_LOG_EVENT_STATUS +
NAME_LEN + 1. That is the space required to do in one write what
Query_log_event::write() does in a bunch of writes:

 return (write_header(file, event_length) ||
          my_b_safe_write(file, (uchar*) buf, QUERY_HEADER_LEN) ||
          write_post_header_for_derived(file) ||
          my_b_safe_write(file, (uchar*) start_of_status,
                          (uint) (start-start_of_status)) ||
          my_b_safe_write(file, (db) ? (uchar*) db : (uchar*)"", db_len
+ 1) ||
          my_b_safe_write(file, (uchar*) query, q_len)) ? 1 : 0;

I misunderstood your comment so that this should be refactored into a
single write.

Regards
Ingo
-- 
Ingo Strüwing, Database Group
Sun Microsystems GmbH, Sonnenallee 1, D-85551 Kirchheim-Heimstetten
Geschäftsführer: Thomas Schröder, Wolfgang Engels, Dr. Roland Bömer
Vorsitzender des Aufsichtsrates: Martin Häring   HRB München 161028