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From:Rick James Date:July 16 2012 4:56pm
Subject:RE: mysql - uppoer limit for doing simultaneous red/writes..
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What does "simultaneous connection" mean?  1000 open connections is reasonable; 10
_active_ connections is reasonable; 1000-10000 queries/second may be reasonable.

If these are readonly connections, then you could set up any number of Slaves.  100 Slaves
with 1000 connections each would achieve 100K "simultaneous connections"?

By "writes" do you mean INSERTs?  Or UPDATEs?  Or DELETEs?

Regular disks cannot handle more than 100 I/Os per second.  RAID, SSD, etc can help some. 
But it is essentially impossible (due to I/O) to do more than 1K _random_ writes per
second.

Describe your application further; there may be ways to make it work.

Is this a web app?  Web connections cannot (and should not) be persistent.  If you have
2000 Apache servers, each with MaxClients=25, that is 50K "connections" from the user's
point of view.  But the connections to MySQL can (should) come and go rapidly enough so
there may not be an issue.

Please estimate "queries per second", and "writes per second", not "simultaneous
connections".

> -----Original Message-----
> From: Reindl Harald [mailto:h.reindl@stripped]
> Sent: Saturday, July 14, 2012 11:19 AM
> To: mysql@stripped
> Subject: Re: mysql - uppoer limit for doing simultaneous red/writes..
> 
> 
> 
> Am 14.07.2012 19:16, schrieb bruce:
> > Hi.
> >
> > Considering a system, where I have a centralized Mysql setup. I'm not
> > sure exactly what this should be called, single box, cluster, etc...
> >
> > But I'm looking to have a system of a a bunch of boxes, whihc run
> apps
> > that will access (read/write) to the different dbs/tbls on the mysql
> > setup.
> >
> > I'm trying to get a feel for just what mysql can handle in this
> situation.
> >
> > Can a mysql setup handle 50K-100K simultaneous connections
> > (reads/writes) to the same db..
> 
> simply no
> 
> you need around 1-2 MB per connection memory besides locking, IOPS and
> other scale troubles
> 
> you would nee at least 35-50 GB RAM for this
> 
> but however, 50k connections are not realistic from where should they
> come? mysqld would be not the only bottenleck

Thread
mysql - uppoer limit for doing simultaneous red/writes..bruce14 Jul
  • Re: mysql - uppoer limit for doing simultaneous red/writes..Reindl Harald14 Jul
    • RE: mysql - uppoer limit for doing simultaneous red/writes..Rick James16 Jul