Hi Dmitri,
Dmitri Lenev, 20.06.2007 21:57:
...
> 6) reopen_table(), reopen_tables():
>
> Remove those usages of reopen_table()/reopen_tables() which are not
> associated with reopening table under LOCK TABLES (i.e. get rid of
> its usage within wait_for_tables()). This will simplify changing of
> reopen_table() in such way that it will safely handle merge tables.
wait_for_tables() is used in mysql_lock_tables() only. It is called when
not all locks could be taken and we need to wait for the tables to be
refreshed before we can try again.
I do not understand what we could replace for reopen_tables(). All
tables are still open and listed in thd->open_tables, including the
MERGE children. Tables that need refresh have closed their handlers.
They need a low-level re-open only. A possible alternative, I could
think of would be to leave mysql_lock_tables with an error code after
waiting for refresh, and start a new cycle in open_and_lock_tables().
But this can only be done when mysql_lock_tables() had been called from
there. It is not an option in other cases. So what do you suggest to
replace for reopen_tables()?
Another thing is that I don't see yet, why it would help us. I don't see
a problem in making reopen_tables() MERGE safe (yet).
Can you please help, before I try the impossible? ;-)
...
Possible problem: in reopen_tables() we report an error for each failed
reopen_table(), but we do still take locks on the successfully opened
tables. Is this required/desirable? Don't we need to abort after
reopen_tables() anyway?
Regards
Ingo
--
Ingo Strüwing, Senior Software Developer
MySQL GmbH, Dachauer Str. 37, D-80335 München
Geschäftsführer: Kaj Arnö - HRB München 162140
