FD_SETSIZE is defined at /usr/include/linux/posix_types.h and /usr/include/bits/typesizes.h ...
Set open_files_limit bigger is a way to let mysql use more file descriptors( and thus has the chance to reach the FD_SETSIZE limit ) Also notice in the bug description, innodb_open_files was used, together with innodb_file_per_table. I guess this does not affect the bug, which occurs at sql/mysqld.cc. :-P 2010/2/2 Wagner Bianchi <wagnerbianch...@gmail.com>: > Sorry, *open_files_limit... > > 2010/2/1 Wagner Bianchi <wagnerbianch...@gmail.com> >> >> Is FD_SETSIZE regards to an open_file_limit? >> >> WB >> >> 2010/2/1 Cui Shijun <rancp...@gmail.com> >>> >>> Got your idea. >>> Thank you very much. Now I know how table cache works :-) >>> >>> For the bug, yes, it's related to the value of FD_SETSIZE, which is >>> limited to 1024 at my RedHat box. >>> Maybe I should update it to a suitable value. >>> >>> 2010/2/2 Johan De Meersman <vegiv...@tuxera.be>: >>> > >>> > On Mon, Feb 1, 2010 at 4:51 PM, Cui Shijun <rancp...@gmail.com> wrote: >>> >> >>> >> I'm also confused by the difference & relationship between "open >>> >> table" and "open file descriptor" by the table cache. >>> > >>> > "open table" is a MySQL concept. "Open file descriptor" is an OS >>> > concept. A >>> > single table (MyISAM) consists of three files: the .frm (description), >>> > the >>> > .MYD (data) and the .MYI (indices). Thus, a single open table can >>> > correspond >>> > to multiple open files. Additionally, temp tables, sortfiles and >>> > whatnot >>> > also consume file descriptors. >>> > >>> >> >>> >> As far as I understand, when a thread ask the global cache for a >>> >> table: >>> >> * if the table is opened before and currently not used by other >>> >> thread, the request thread will get this table >>> > >>> > "and *there is a cache entry that* is currently not used*" - multiple >>> > entries can exist for the same table. >>> > >>> >> >>> >> * if no table in table cache is available( currently used by other >>> >> thread, or not opened before ), the request thread will open this >>> >> table >>> > >>> > The thread will get a new cache object that opens that table, yes. >>> > >>> >> >>> >> Once open a table, mysql *might?( I'm not sure )* open a file >>> >> descriptor corresponding to the data file of the table. In that case, >>> >> when the number of table opened simultaneously goes too big, mysql >>> >> will use too much file descriptors and then hit the bug 48929. >>> >> >>> >> Your experience( "I've had one occurrence where it grew to 26.000 >>> >> open tables" ) seems to show there must be something wrong with my >>> >> understanding, Hmm... :-( >>> > >>> > I just skimmed over it, but the bug seem related specifically to >>> > InnoDB, and >>> > to a highly specific file descriptor number being equal to some form of >>> > hardcoded limit - maybe different OSes or linux distro's have different >>> > values for said limit, or maybe it only occurs under specific >>> > conditions. >>> > >>> > >>> > >>> > -- >>> > Bier met grenadyn >>> > Is als mosterd by den wyn >>> > Sy die't drinkt, is eene kwezel >>> > Hy die't drinkt, is ras een ezel >>> > >>> >>> -- >>> MySQL General Mailing List >>> For list archives: http://lists.mysql.com/mysql >>> To unsubscribe: >>> http://lists.mysql.com/mysql?unsub=wagnerbianch...@gmail.com > > > -- > Wagner Bianchi - Web System Developer and Database Administrator > Phone: (31) 8654-9510 / 3272-0226 > E-mail: wagnerbianch...@gmail.com > Lattes: http://lattes.cnpq.br/2041067758113940 > Twitter: http://twitter.com/wagnerbianchi > Skype: infodbacet > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
