Re: What degree of concurrency does MySQL support?
We are thinking of moving to MySQL. We have a table of several tens of millions of rows, with two indices, which will be accessed by roughly 100 different processes. At any one time, 5 or so of the processes will be doing selects on the table, while 40 or so will be doing updates. However, no two processes will ever try to update the same row at once. Can MySQL handle this efficiently and without allowing the table or indices to become corrupt? (The total throughput we need is on the order of 100 indexed updates per second; currently we are running a single 900 MHz Athlon with generic IDE disk but would buy more processors if it would help). MySQL has only table level locking, which means that each update will lock the entire table, which means that updates must be done one at a time. There are a couple of open source extensions of MySQL that are supposed to offer row level locking, but these aren't available yet. Bob Hall Know thyself? Absurd direction! Bubbles bear no introspection. -Khushhal Khan Khatak - 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: What degree of concurrency does MySQL support?
On Fri, Jan 19, 2001 at 06:58:34AM -0500, Bob Hall wrote: MySQL has only table level locking, which means that each update will lock the entire table, which means that updates must be done one at a time. There are a couple of open source extensions of MySQL that are supposed to offer row level locking, but these aren't available yet. With BDB tables, you get page-level locking, right? Jeremy -- Jeremy D. Zawodny, [EMAIL PROTECTED] Technical Yahoo - Yahoo Finance Desk: (408) 328-7878Fax: (408) 530-5454 Cell: (408) 439-9951 - 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: What degree of concurrency does MySQL support?
On Fri, Jan 19, 2001 at 06:58:34AM -0500, Bob Hall wrote: MySQL has only table level locking, which means that each update will lock the entire table, which means that updates must be done one at a time. There are a couple of open source extensions of MySQL that are supposed to offer row level locking, but these aren't available yet. With BDB tables, you get page-level locking, right? Yes sir, I think you are right. BDB has to be compiled into MySQL, and the remarks in the online documentation suggest that MySQL with BDB compiled in isn't quite as stable as MySQL alone. Also, BDB tables are not as fast as MySQL without BDB tables. The original poster didn't ask about BDB tables and I don't have any experience with them. If you do, perhaps you could describe how the performance characteristics of MySQL with BDB tables compare with the original poster's needs. I'd be very interested in learning about it. Bob Hall Know thyself? Absurd direction! Bubbles bear no introspection. -Khushhal Khan Khatak - 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: What degree of concurrency does MySQL support?
As far as hardware goes, you should be able to increase performance with more RAM and faster disks such as UW-160 SCSI. Also, I don't think they make dual processor motherboards for Athalons. - Scott (The total throughput we need is on the order of 100 indexed updates per second; currently we are running a single 900 MHz Athlon with generic IDE disk but would buy more processors if it would help). - 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
