Happy Christmas
Hope you are all having a Happy Christmas. Regards Peter -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql?unsub=arch...@jab.org
Re: UPDATE and simultaneous SELECT ... similar to RETURNING?
Dante, On Tue, Dec 22, 2009 at 3:53 PM, Dante Lorenso da...@lorenso.com wrote: All, There was a feature of another DB that I have grown extremely accustomed to and would like to find the equivalent in MySQL: UPDATE mytable SET mycolumn = mycolumn + 1 WHERE mykey = 'dante' RETURNING mycolumn; I know what you're talking about. It doesn't exist in MySQL and I would not expect it to be added soon. (Probably not ever, but that's just a guess.) - Baron -- Baron Schwartz Percona Inc: Services and Support for MySQL http://www.percona.com/ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql?unsub=arch...@jab.org
Re: mysql load balancing
Miguel, On Sun, Dec 20, 2009 at 6:21 PM, Miguel Angel Nieto cor...@miguelangelnieto.net wrote: Hi, I am searching fot a Mysql Load Balacing tool. I read about mysql proxy, sqlrelay, haproxy... Load balancing, or high availability? I do not think there is anything good and simple AND generic out of the box. As previous posters have noted, you generally have to build something on top of other tools. - Baron -- Baron Schwartz Percona Inc: Services and Support for MySQL http://www.percona.com/ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql?unsub=arch...@jab.org
RE: Happy Christmas
Guten Tag/Bonjour/Hello Pete Haben Sie ein gutes Weihnachten/Ayez bon Noël/Have a good Christmas Staaten von Amerika/Etats Unis/United States of America Martin Gainty __ Verzicht und Vertraulichkeitanmerkung/Note de déni et de confidentialité Diese Nachricht ist vertraulich. Sollten Sie nicht der vorgesehene Empfaenger sein, so bitten wir hoeflich um eine Mitteilung. Jede unbefugte Weiterleitung oder Fertigung einer Kopie ist unzulaessig. Diese Nachricht dient lediglich dem Austausch von Informationen und entfaltet keine rechtliche Bindungswirkung. Aufgrund der leichten Manipulierbarkeit von E-Mails koennen wir keine Haftung fuer den Inhalt uebernehmen. Ce message est confidentiel et peut être privilégié. Si vous n'êtes pas le destinataire prévu, nous te demandons avec bonté que pour satisfaire informez l'expéditeur. N'importe quelle diffusion non autorisée ou la copie de ceci est interdite. Ce message sert à l'information seulement et n'aura pas n'importe quel effet légalement obligatoire. Étant donné que les email peuvent facilement être sujets à la manipulation, nous ne pouvons accepter aucune responsabilité pour le contenu fourni. From: pbsb...@googlemail.com To: mysql@lists.mysql.com Subject: Happy Christmas Date: Fri, 25 Dec 2009 10:33:35 + Hope you are all having a Happy Christmas. Regards Peter -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql?unsub=mgai...@hotmail.com _ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/177141665/direct/01/
Re: two processes update the same column in short time
On Fri, 25 Dec 2009 15:41:40 +0800 Eva said:
Hello,
I have a table, say its stru is like:
domain ip noticed
The column noticed is an enum value (eigher 0 or 1).
When process one update ip, it will set noticed to 0.
Then process two know the status changed, it will do something and set
noticed to 1.
What the problem I meet is, when process two read ip from the table, and
before it update the noticed to 1 (it has to do something with the ip, and
this will take few seconds), process one also updated the table with new ip
and noticed=0. Under this case, process two has gotten the outdated IPs (not
the new ones updated by process one), since it will set noticed=1 finally so
it doesn't have a chance to find it's using old IPs.
So how to resolve this problem?
Thanks for my newbie questions.
Merry Holidays!
Eva.
Change noticed to enum('new', 'scan', 'done') not null default 'new';
When proc two runs, it should
UPDATE noticed='scan' WHERE noticed='new'
Then repeat the scan with SELECT ... WHERE noticed='scan'
...
and finally it should UPDATE domain=whatever, ... noticed='done'
Regards,
--
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steal the neighbor's newspaper, that's the time to do it.
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Re: mysql load balancing
Load balancing, or high availability? I do not think there is anything good and simple AND generic out of the box. As previous posters have noted, you generally have to build something on top of other tools. Hi, I have the HA solved with MMM. Now, I want load balacing, sending read queries to slaves and write queries to masters. I read about mysql proxy, sqlrelay... but I didn't know the difference betwen them, and the possible problems of each tool (latency for example). If anyone, like Pascal, have experience with those kind of tools, please, share them :P -- Lo que haría sería hacerme pasar por sordomudo y así no tendría que hablar. Si querían decirme algo, tendrían que escribirlo en un papelito y enseñármelo. Al final se hartarían y ya no tendría que hablar el resto de mi vida. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql?unsub=arch...@jab.org
Re: two processes update the same column in short time
2009-12-26 2:36, Don Read :
Change noticed to enum('new', 'scan', 'done') not null default 'new';
When proc two runs, it should
UPDATE noticed='scan' WHERE noticed='new'
Then repeat the scan with SELECT ... WHERE noticed='scan'
...
and finally it should UPDATE domain=whatever, ... noticed='done'
Thanks Don.
That means, when process one want to update ip but it see
noticed=scan, it will block until the status become done, is it?
Eva
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RE: mysql load balancing
Baron: Load balancing, or high availability? I do not think there is anything good and simple We use MySQL master-master replication to keep geographically separated databases in sync. It works very well. We built a management layer on top of it to allow the endpoints (Web servers) to talk to either database in case one fails. That is not necessary but it adds a extra layer of proctection. Neil -- Neil Aggarwal, (281)846-8957, http://UnmeteredVPS.net Host your MySQL database on a CentOS virtual server for $25/mo Unmetered bandwidth = no overage charges, 7 day free trial -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql?unsub=arch...@jab.org
Re: two processes update the same column in short time
On Sat, 26 Dec 2009 10:43:55 +0800 Eva said:
2009-12-26 2:36, Don Read :
Change noticed to enum('new', 'scan', 'done') not null default 'new';
When proc two runs, it should
UPDATE noticed='scan' WHERE noticed='new'
Then repeat the scan with SELECT ... WHERE noticed='scan'
...
and finally it should UPDATE domain=whatever, ... noticed='done'
Thanks Don.
That means, when process one want to update ip but it see
noticed=scan, it will block until the status become done, is it?
Eva
Depends on how closely coupled the two processes are.
a. proc #1 can only insert new ip's (INSERT IGNORE)
b. proc #1 could ignore/refuse to update any ip not 'new'
c. proc #1 could leave the noticed field alone.
d. proc #1 could set noticed to 'new' (and let proc #2 scan it again)
Which alternative works best for your application?
Regards,
--
Don Readdon_r...@att.net
It's always darkest before the dawn. So if you are going to
steal the neighbor's newspaper, that's the time to do it.
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