Re: Table Lock
Hi! sangprabv wrote: Hi, Is that true that MySQL lock table on each query? Does it means will cause slow speed? Then how to avoid table lock and speed up MySQL? TIA. You need to read up about the different table handlers available. They have different properties, including the locking behavior. Check the manual for the version you are using. Jörg -- Joerg Bruehe, MySQL Build Team, joerg.bru...@sun.com Sun Microsystems GmbH, Sonnenallee 1, D-85551 Kirchheim-Heimstetten Geschaeftsfuehrer: Thomas Schroeder, Wolfgang Engels, Dr. Roland Boemer Vorsitzender des Aufsichtsrates: Martin Haering Muenchen: HRB161028 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql?unsub=arch...@jab.org
Re: table lock
Eli Shemer wrote: The web site on the other end reads all the data from the table and generates standard html/css code with the information from the table. How can I make all of the apache child processes wait for the external script to complete its operation once it has started? Alternatively, Create a new table which has similar table definition as the one to which your script is writing the data. ' CREATE TABLE new_tbl LIKE orig_tbl; ' populate new_tbl with your data and then rename it to orig_tbl - 'rename table new_tbl to orig_tbl' (rename is atomic operation) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: table lock
Good Morning Eli I would consider implementation of mpm_common more specifically enabling inter process communication with mutex's such as what you see at http://httpd.apache.org/docs/2.0/mod/mpm_common.html#acceptmutex and then utilising the flock directive to either lock/unlock a file such such as described here http://httpd.apache.org/docs/2.0/mod/mpm_common.html#lockfile Martin - Original Message - From: Eli Shemer [EMAIL PROTECTED] To: mysql@lists.mysql.com Sent: Sunday, March 02, 2008 10:06 AM Subject: table lock Hey there I have an external script that generates a lot of data and dumps it into a table. Prior to this ,it removes all the data in this specific table. It requires both read and write privileges. The web site on the other end reads all the data from the table and generates standard html/css code with the information from the table. How can I make all of the apache child processes wait for the external script to complete its operation once it has started? What would be the best way for this ? Thanks! Internal Virus Database is out-of-date. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.16.4/1146 - Release Date: 22/11/2007 18:55 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Table Lock issue on insert
John, this SQL statement: INSERT INTO USERS_PER_HOUR SELECT count( DISTINCT ( CUID ) ),`TV_LOG_DATE`,`TV_LOG_TIME`, INTERFACE_ID FROM `TV_LOG_ALL` group by 2,3; sets locks on all the records it scans in TV_LOG_ALL. If you have a small buffer pool, then the InnoDB lock table may indeed grow so big that it does not fit in the buffer pool. The default size of the buffer pool is just 8 MB. Fix: modify my.cnf and increase innodb_buffer_pool_size. But do not make it bigger than about 70 % of your computer's RAM. Best regards, Heikki Oracle Corp./Innobase Oy InnoDB - transactions, row level locking, and foreign keys for MySQL InnoDB Hot Backup - a hot backup tool for InnoDB which also backs up MyISAM tables http://www.innodb.com/order.php - Original Message - From: Danny Stolle [EMAIL PROTECTED] Newsgroups: mailing.database.myodbc Sent: Monday, January 02, 2006 9:31 PM Subject: Re: Table Lock issue on insert Hi John, I have looked around a bit and you might be interested in this part: InnoDB: Do not intentionally crash mysqld if the buffer pool is exhausted by the lock table; return error 1206 instead ... check this link: http://dev.mysql.com/doc/refman/4.1/en/news-4-1-8.html it is quite interesting and i am trying to get this error on my mysql databases by changing the bufferpool and inserting a lot of data; Best regards, Danny Brittingham, John wrote: They are InnoDB and max_write_lock_count=4294967295. The same thing happens when I create a copy of the table. -Original Message- From: Danny Stolle [mailto:[EMAIL PROTECTED] Sent: Saturday, December 31, 2005 2:59 AM To: Brittingham, John; mysql@lists.mysql.com Subject: Re: Table Lock issue on insert Hi John, What kind of engine are you using on your table? MyIsam or InnoDB or are you using merged tables? If you query your system variables what is your max_write_lock_count? If you create a copy of the table: mysqlcreate table cp1 like USERS_PER_HOUR; and you try the insert again; is the error gone? Danny Brittingham, John wrote: I am having trouble with table lock. The query is as follows: INSERT INTO USERS_PER_HOUR SELECT count( DISTINCT ( CUID ) ),`TV_LOG_DATE`,`TV_LOG_TIME`, INTERFACE_ID FROM `TV_LOG_ALL` group by 2,3; I keep getting this error: #1206 - The total number of locks exceeds the lock table size How do I fix this? -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Table Lock issue on insert
Hi john, When did you start getting this error message? There aren't any trouble with MyIsam tables? Danny Brittingham, John wrote: They are InnoDB and max_write_lock_count=4294967295. The same thing happens when I create a copy of the table. -Original Message- From: Danny Stolle [mailto:[EMAIL PROTECTED] Sent: Saturday, December 31, 2005 2:59 AM To: Brittingham, John; mysql@lists.mysql.com Subject: Re: Table Lock issue on insert Hi John, What kind of engine are you using on your table? MyIsam or InnoDB or are you using merged tables? If you query your system variables what is your max_write_lock_count? If you create a copy of the table: mysqlcreate table cp1 like USERS_PER_HOUR; and you try the insert again; is the error gone? Danny Brittingham, John wrote: I am having trouble with table lock. The query is as follows: INSERT INTO USERS_PER_HOUR SELECT count( DISTINCT ( CUID ) ),`TV_LOG_DATE`,`TV_LOG_TIME`, INTERFACE_ID FROM `TV_LOG_ALL` group by 2,3; I keep getting this error: #1206 - The total number of locks exceeds the lock table size How do I fix this? -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Table Lock issue on insert
Hi John, I have looked around a bit and you might be interested in this part: InnoDB: Do not intentionally crash mysqld if the buffer pool is exhausted by the lock table; return error 1206 instead ... check this link: http://dev.mysql.com/doc/refman/4.1/en/news-4-1-8.html it is quite interesting and i am trying to get this error on my mysql databases by changing the bufferpool and inserting a lot of data; Best regards, Danny Brittingham, John wrote: They are InnoDB and max_write_lock_count=4294967295. The same thing happens when I create a copy of the table. -Original Message- From: Danny Stolle [mailto:[EMAIL PROTECTED] Sent: Saturday, December 31, 2005 2:59 AM To: Brittingham, John; mysql@lists.mysql.com Subject: Re: Table Lock issue on insert Hi John, What kind of engine are you using on your table? MyIsam or InnoDB or are you using merged tables? If you query your system variables what is your max_write_lock_count? If you create a copy of the table: mysqlcreate table cp1 like USERS_PER_HOUR; and you try the insert again; is the error gone? Danny Brittingham, John wrote: I am having trouble with table lock. The query is as follows: INSERT INTO USERS_PER_HOUR SELECT count( DISTINCT ( CUID ) ),`TV_LOG_DATE`,`TV_LOG_TIME`, INTERFACE_ID FROM `TV_LOG_ALL` group by 2,3; I keep getting this error: #1206 - The total number of locks exceeds the lock table size How do I fix this? -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Table Lock issue on insert
Hi John, What kind of engine are you using on your table? MyIsam or InnoDB or are you using merged tables? If you query your system variables what is your max_write_lock_count? If you create a copy of the table: mysqlcreate table cp1 like USERS_PER_HOUR; and you try the insert again; is the error gone? Danny Brittingham, John wrote: I am having trouble with table lock. The query is as follows: INSERT INTO USERS_PER_HOUR SELECT count( DISTINCT ( CUID ) ),`TV_LOG_DATE`,`TV_LOG_TIME`, INTERFACE_ID FROM `TV_LOG_ALL` group by 2,3; I keep getting this error: #1206 - The total number of locks exceeds the lock table size How do I fix this? -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Table Lock Delays and Connection Pooling
Every new connection is considered a client. It's a bad idea to try to do your own scheduling client side to try to defeat table locks because MySQL can proceed with other clients as soon as the locks are freed vs your application waiting for a complete result set to return before proceeding with another query from a different client. Not to mention the over head of scheduling on the client side. If you have enough lock contention for table locks to be a problem you should switch to the InnoDB storage engine. -- Eric Bergen [EMAIL PROTECTED] On Mon, 18 Oct 2004 16:58:04 -0700, Aaron [EMAIL PROTECTED] wrote: Hi all , I have a quick question regarding table locking. This is a snippet referring to when table locking is disadvantageous: Another client issues another SELECT statement on the same table. Because UPDATE has higher priority than SELECT, this SELECT will wait for the UPDATE to finish. It will also wait for the first SELECT to finish! So what constitutes a new client exactly? We use Perl and DBI to connect to MySQL. Does this mean that everytime we connect to the DBase it is considered a new client? If so , would some form of connection pooling/caching help reduce the lock delays on a slow SELECT statement? Thanks ! Aaron -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Table lock problem on INSERT with FULLTEXT index?
FWIW, I'm still having this problem. I've completely dropped the table and re-built it from the ground up. It's a bizarre problem... The table is totally simple. A primary key, and then three varchar fields. The FULLTEXT index spans the 3 varchar fields. There are only 6500+ rows, so it's pretty tiny. A mysqldump of the table is only 442K. Has no-one else seen anything like this? I can't imagine I'm the only one. Thanks, Don Don MacAskill wrote: Hi there, I've got a bizarre problem I can't seem to solve. I have a small MyISAM table (6533 rows) with a small FULLTEXT index (3 columns per row, an average of 1 word per column). When I do an INSERT on the table, many times the thread gets stuck perpetually in Query | update. Future reads from other threads, of course, stay Locked. When I try to kill the thread using mysqladmin, the thread sticks around for thousands of seconds in Killed | update until I finally just have to kill mysqld manually and let it restart. I've tried REPAIR, ANALYZE, and OPTIMIZE on the table, both using mysql and myisamchk. Tried all the options, such as extended and force and the like. I've even tried wrapping the INSERT with LOCK TABLE table WRITE and UNLOCK TABLES. Still no dice, the INSERT still hangs sometimes. I haven't bothered trying INSERT DELAYED since LOCK TABLE seems more drastic anyway and it didn't work. This happens both on 4.0.17 and 4.0.18. This is a RHEL3 WS dual AMD64 box w/8GB of RAM. Strangely enough, I have another MyISAM table with 1,285,742 rows and a larger FULLTEXT index, and it never locks this way. I have a third MyISAM table with 61,834 rows and a larger FULLTEXT index that locked on me once like this last night, but then I ran through and updated nearly every row overnight, and inserted a few hundred new ones, and it didn't lock at all. FWIW, it only seems to hang on INSERT, not on UPDATE. I haven't tried DELETE yet. I'm stumped. Any help would be greatly appreciated! Thanks, Don -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Table lock statistics by TABLE not just server,db
On Fri, Jan 09, 2004 at 01:43:53PM -0800, trevor%tribenetwork.com wrote: Mysqlians, I am trying to determine in some of my database tables should be converted from MyISAM to Innodb. I have read that a collusion on 10-20% is the threshold at which one should convert( current # around .3%). However the table_locks_waited and table_locks_immediate counters only give information on a server level. I want to examine this data per table. Does anyone know how to do this? MySQL doesn't yet provide locking data more granular than that. Perhaps using a very low long query time and enabling the slow query log would help? Jeremy -- Jeremy D. Zawodny | Perl, Web, MySQL, Linux Magazine, Yahoo! [EMAIL PROTECTED] | http://jeremy.zawodny.com/ MySQL 4.0.15-Yahoo-SMP: up 118 days, processed 510,213,828 queries (50/sec. avg) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: table lock - which connection id own's it
On Wed, Apr 24, 2002 at 12:45:43PM +0300, Michael Widenius wrote: I will add to our TODO to add to SHOW OPEN TABLES a list of threads that has locks on the table (or maybe a SHOW LOCKS command) to better cover this case in the future. Could it be SHOW TABLE LOCKS? That way it is not confused with the GET_LOCK()/RELEASE_LOCK() stuff? Or at least provide a simple way to differentiate between the two types of locks. I'd like to be able to see table locks some times and the other locks at other times. Jeremy -- Jeremy D. Zawodny, [EMAIL PROTECTED] Technical Yahoo - Yahoo Finance Desk: (408) 349-7878 Fax: (408) 349-5454 Cell: (408) 685-5936 MySQL 3.23.47-max: up 77 days, processed 2,021,067,761 queries (303/sec. avg) - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
RE: table lock - which connection id own's it
Hi! Lopez == Lopez David E-r9374c [EMAIL PROTECTED] writes: cut Lopez If no row is returned, then the following happens: Lopez 1) lock table ... Lopez 2) select ... Lopez 3) if no row is returned, Lopez 4)insert ... Lopez 5)use LAST_INSERT_ID() to get the value of the key Lopez 6) else get the key-value pair Lopez 7) unlock table Lopez 8) put key-value pair in RAM hash Lopez 9) insert row in main table (using new key-value pair) Why not instead do as follows: (This assumes you have an unique index on the thing you are selecting on) select ... if no row is returned, insert ... if insert works without a duplicate key error: use LAST_INSERT_ID() to get the value of the key else select to find the row some other thread inserted put key-value pair in RAM hash insert row in main table (using new key-value pair) cut Lopez Hope that clears the insertion process on the hash tables. I'm Lopez glad that if a connection is lost in steps 2-6, mysql would Lopez automatically unlock the tables. That will satisfy the db Lopez specification nicely. The architecture for our db came Lopez from the optimization chapter in the manual. Thanks! If the connection dies on the client side, the server will notice it as once. The thing you will not notice if a client goes into an endless loop and will not release the connection to the MySQL server. I will add to our TODO to add to SHOW OPEN TABLES a list of threads that has locks on the table (or maybe a SHOW LOCKS command) to better cover this case in the future. Regards, Monty -- For technical support contracts, goto https://order.mysql.com/ __ ___ ___ __ / |/ /_ __/ __/ __ \/ /Mr. Michael Widenius [EMAIL PROTECTED] / /|_/ / // /\ \/ /_/ / /__ MySQL AB, CTO /_/ /_/\_, /___/\___\_\___/ Helsinki, Finland ___/ www.mysql.com - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
RE: table lock - which connection id own's it
Monty BTW, it's a thrill to hear from the CTO. The procedure for locking a table is more complex but will attempt to describe it further for you. Any of the 150 daemons can insert to the hash tables. The data in the row can be used by all 150 daemons. The primary key in hash table is the id field which is an auto-increment type. This id field is the hash value inserted in the main table as foreign key. When a daemon starts up, it reads the hash table with each entry a key-value pair. The value is the id field. During the course of logging info to the main table, it may find an entry that is not in it's local hash in RAM. When this occurs, it does a sql select on the hash. If a row is returned, it will insert the key-value pair into the it's hash and insert an entry into the main table. If no row is returned, then the following happens: 1) lock table ... 2) select ... 3) if no row is returned, 4)insert ... 5)use LAST_INSERT_ID() to get the value of the key 6) else get the key-value pair 7) unlock table 8) put key-value pair in RAM hash 9) insert row in main table (using new key-value pair) Since 99% of the time, the data hash table information is already stored in the daemon hash table on initial start up. We wanted to lock the table so two different daemons would not enter the same information in the hash tables. Extremely unlikely, but the boss is paranoid. Or is it more experienced. Hope that clears the insertion process on the hash tables. I'm glad that if a connection is lost in steps 2-6, mysql would automatically unlock the tables. That will satisfy the db specification nicely. The architecture for our db came from the optimization chapter in the manual. Thanks! David -Original Message- From: Michael Widenius [mailto:[EMAIL PROTECTED]] Sent: Tuesday, April 23, 2002 12:59 AM To: Lopez David E-r9374c Cc: Mysql List (E-mail) Subject: table lock - which connection id own's it Hi! Lopez == Lopez David E-r9374c [EMAIL PROTECTED] writes: Lopez AntiSpam - mysql, sql, query Lopez Version: 3.23.49a, MyISAM, NT, Solaris Lopez My app is 150 daemons writing logs to mysql. The main Lopez table is of fixed size but depends on four other tables Lopez for foreign keys (hash tables). These tables are uploaded Lopez once to the daemon at start-up. Occasionally, a new entry Lopez must be written into these hash tables. The procedure is Lopez to lock the table, insert entry, get the key (auto-increment Lopez field) and release the lock. A better solution is to use LAST_INSERT_ID() and not use any locks at all. Lopez But what if the connection dies during the update process. Lopez If this happens, how can I tell which connection id has the Lopez lock so I can kill it? If a connection dies, the server will automaticly delete all temporary tables and all table locks. Regards, Monty -- For technical support contracts, goto https://order.mysql.com/ __ ___ ___ __ / |/ /_ __/ __/ __ \/ /Mr. Michael Widenius [EMAIL PROTECTED] / /|_/ / // /\ \/ /_/ / /__ MySQL AB, CTO /_/ /_/\_, /___/\___\_\___/ Helsinki, Finland ___/ www.mysql.com - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
RE: table lock - which connection id own's it
Lopez David E-r9374c writes: Monty BTW, it's a thrill to hear from the CTO. The procedure for locking a table is more complex but will attempt to describe it further for you. Any of the 150 daemons can insert to the hash tables. The data in the row can be used by all 150 daemons. The primary key in hash table is the id field which is an auto-increment type. This id field is the hash value inserted in the main table as foreign key. When a daemon starts up, it reads the hash table with each entry a key-value pair. The value is the id field. During the course of logging info to the main table, it may find an entry that is not in it's local hash in RAM. When this occurs, it does a sql select on the hash. If a row is returned, it will insert the key-value pair into the it's hash and insert an entry into the main table. If no row is returned, then the following happens: 1) lock table ... 2) select ... 3) if no row is returned, 4)insert ... 5)use LAST_INSERT_ID() to get the value of the key 6) else get the key-value pair 7) unlock table 8) put key-value pair in RAM hash 9) insert row in main table (using new key-value pair) Since 99% of the time, the data hash table information is already stored in the daemon hash table on initial start up. We wanted to lock the table so two different daemons would not enter the same information in the hash tables. Extremely unlikely, but the boss is paranoid. Or is it more experienced. Hope that clears the insertion process on the hash tables. I'm glad that if a connection is lost in steps 2-6, mysql would automatically unlock the tables. That will satisfy the db specification nicely. The architecture for our db came from the optimization chapter in the manual. Thanks! David Hi! Still , locking a table is not necessary as MySQL server remembers LAST_INSERT_ID() value, for each connection (thread) separately. Simply, this value is not (only) remembered on per-table basis, but also for each thread (connection) separately. -- Regards, __ ___ ___ __ / |/ /_ __/ __/ __ \/ /Mr. Sinisa Milivojevic [EMAIL PROTECTED] / /|_/ / // /\ \/ /_/ / /__ MySQL AB, Fulltime Developer /_/ /_/\_, /___/\___\_\___/ Larnaca, Cyprus ___/ www.mysql.com - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
Re: Table Lock
Hi Hayan, have a look at: http://www.mysql.com/doc/L/O/LOCK_TABLES.html for information on (un)locking tables. At 11:48 28.01.02 +0300, you wrote: Hi, Is there a way to lock a table so that only one user can change it and then unlockit? I need to do this coz I want visitors to retrieve some values from a database but each value must be retrieved only by one user and then marked up to be expired, so I don't want two users to retrieve the same value Any suggestions Best Regards Hayan - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php urbia Grüße - best regards Tobias Kremer Webmaster / Software-Entwicklung urbia.com AG Hohe Str.115, 50667 Köln tel:+49 (0)221 - 2949 154 fax:+49 (0)221 - 2949 599 e-mail: [EMAIL PROTECTED] http://www.urbia.de - we are family http://www.urbia.fr - votre espace famille http://www.urbia.co.uk - the family site Linux is like a wigwam. No gates, no windows but an apache inside - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
RE: Table Lock
Yes, i need this too but for a whole database. i just thought, if there is a power loss, and the database is get stuck, the users won't able to connect again ... Vaso -Original Message- From: Hayan Al Mamoun [mailto:[EMAIL PROTECTED]] Sent: 2002. janu?r 28. 9:48 To: MYSQL MAILING LIST (E-mail) Subject: Table Lock Hi, Is there a way to lock a table so that only one user can change it and then unlockit? I need to do this coz I want visitors to retrieve some values from a database but each value must be retrieved only by one user and then marked up to be expired, so I don't want two users to retrieve the same value Any suggestions Best Regards Hayan - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
RE: Table Lock
Vasoczki, Monday, January 28, 2002, 12:20:21 PM, you wrote: VF Yes, i need this too but for a whole database. i just thought, if there is a VF power loss, and the database is get stuck, the users won't able to connect VF again ... It should be a very fanciful power failure and hardware failure in order to end up with a stuck database under MySQL... So I can't get you - do you need to _lock_ the database in case of power failure OR you are afraid of such a possibility? VF Vaso -- For technical support contracts, goto https://order.mysql.com/ This email is sponsored by Ensita.net http://www.ensita.net/ __ ___ ___ __ / |/ /_ __/ __/ __ \/ /Egor Egorov / /|_/ / // /\ \/ /_/ / /__ [EMAIL PROTECTED] /_/ /_/\_, /___/\___\_\___/ MySQL AB / Ensita.net ___/ www.mysql.com - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
Re: table lock
On Mon, Jan 28, 2002 at 12:00:43PM -0500, bin cai wrote: Hi, I have one concern about multithread. I am building online exam system. many students can get access to one table in one time. Should i use table lock every time when one student get access to the table. As i know, mysql is multithread,that means it already incorporate the table lock feature? Thank you bin MySQL handles it automatically. -- Jeremy D. Zawodny, [EMAIL PROTECTED] Technical Yahoo - Yahoo Finance Desk: (408) 349-7878 Fax: (408) 349-5454 Cell: (408) 685-5936 MySQL 3.23.41-max: up 25 days, processed 564,305,249 queries (252/sec. avg) - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
