It would be great if there is a swap table command that is atomic. Thanks a lot
Haitao On Tue, 10 Aug 2004 13:23:30 +0300, Egor Egorov <[EMAIL PROTECTED]> wrote: > Haitao Jiang <[EMAIL PROTECTED]> wrote: > > > Thanks so much for the reply! So, if I understand correctly, to swap > > the table like I described, I should do: > > > > LOCK TABLES A write,A2 write; > > FLUSH TABLES; > > rename table A to A1; > > rename table A2 to A; > > UNLOCK TABLES; > > > > Right? If there is no write to either A or A2, then there is no need > > to lock the table, right? > > You can't rename locked tables. RENAME is atomic anyway so you can safely use > it without lock. But your software should be aware of a possible race condition > that happens between two RENAME TABLEs. > > > > > > Thanks! > > > > On Mon, 09 Aug 2004 19:21:39 +0300, Egor Egorov <[EMAIL PROTECTED]> wrote: > >> Haitao Jiang <[EMAIL PROTECTED]> wrote: > >> > >> > Case 1: I have a table A under a running MySQL 4.1.3b server. If I > >> > replace A.MYD and A.MYI files without stop and start the server, will > >> > data gets corrupted? > >> > >> It depends on many factors. Honestly, there are lots of cases where you will > >> get correct data and nothing wrong will happen. But you have to be an > >> experience Unix developer to understand Unix internals in order to dance like > >> that. :) > >> > >> So the general answer is: don't, it's too dangerous. > >> > >> > Case 2: I rename A to A1, and A2 to A, assume A, A2 have the same > >> > schema but different data/index. Is it bad? Will data gets corrupted? > >> > I tied this one, it seems ok. > >> > >> Yes, you're right, it just *SEEMS* ok. :) > >> > >> If you really need to replace table files, use FLUSH TABLES, LOCK TABLES: > >> > >> http://dev.mysql.com/doc/mysql/en/FLUSH.html > >> http://dev.mysql.com/doc/mysql/en/LOCK_TABLES.html > >> > >> -- > >> For technical support contracts, goto https://order.mysql.com/?ref=ensita > >> This email is sponsored by Ensita.net http://www.ensita.net/ > >> __ ___ ___ ____ __ > >> / |/ /_ __/ __/ __ \/ / Egor Egorov > >> / /|_/ / // /\ \/ /_/ / /__ [EMAIL PROTECTED] > >> /_/ /_/\_, /___/\___\_\___/ MySQL AB / Ensita.net > >> <___/ www.mysql.com > >> > >> > >> -- > >> MySQL General Mailing List > >> For list archives: http://lists.mysql.com/mysql > >> To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] > >> > >> > > > > -- > For technical support contracts, goto https://order.mysql.com/?ref=ensita > This email is sponsored by Ensita.net http://www.ensita.net/ > __ ___ ___ ____ __ > / |/ /_ __/ __/ __ \/ / Egor Egorov > / /|_/ / // /\ \/ /_/ / /__ [EMAIL PROTECTED] > /_/ /_/\_, /___/\___\_\___/ MySQL AB / Ensita.net > <___/ www.mysql.com > > -- > 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]
