Re: bzr commit into mysql-5.0-bugteam branch (gshchepa:2689) Bug#38691

[Konstantin Osipov]

* Gleb Shchepa <gshchepa@stripped> [08/10/07 16:05]:
>  2689 Gleb Shchepa	2008-10-07
>       Bug #38691: segfault/abort in ``UPDATE ...JOIN'' while
>                 ``FLUSH TABLES WITH READ LOCK''
>       
>       Concurrent execution of 1) multitable update with a
>       NATURAL/USING join and 2) a such query as "FLUSH TABLES
>       WITH READ LOCK" or "ALTER TABLE" of updating table led
>       to a server crash.
>       
>       
>       The mysql_multi_update_prepare() function call is optimized
>       to lock updating tables only, so it postpones locking to
>       the last, and if locking fails, it does cleanup of modified
>       syntax structures and repeats a query analysis.  However,
>       that cleanup procedure was incomplete for NATURAL/USING join
>       syntax data: 1) some Field_item items pointed into freed
>       table structures, and 2) the TABLE_LIST::join_columns fields
>       was not reset.
>       
>       Major change:
>         short-living Field *Natural_join_column::table_field has
>         been replaced with long-living Item*.

Please add select_lex::first_natural_join_processing and use/set
it explicitly in setup_natural_join_row_types() instead of adding
thd->multiupdate_reopen and checking it in
setup_natural_join_row_types().
It's okay to push this patch with this change.

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