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From:Tomas Ulin Date:November 17 2004 5:23pm
Subject:Re: qcache and 4.1.7-max official
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Olivier Kaloudoff wrote:

> On Wed, 17 Nov 2004, Tomas Ulin wrote:
>
>> Correct,
>>
>> query cache is disabled by default in ndb.  This is because it is not 
>> maintained across several mysql servers.  I.e. if you insert a value 
>> in one mysql server this will not be noticed by the query cache in 
>> the other
>> server.  So potential _danger_ in using it.
>
>
> ok. If I understand what you mean, qcache is safe with select operations,
> not with alter, insert, and any write operations.
>
> Additionnaly, it means that if I want to be safe, I have to do write
> operations on a dedicated API node with qcache disabled, which would not
> cause any problem in my case, I'm working with really nice php 
> developpers
> who will know how to handle this softly ;-)
>
>> But, if _you_ want to use it, we can supply a setting for turning it 
>> on _anyway_.  But you need to know the limitaions and dangers of 
>> using it.
>>
>> Please state if you want to use it.
>
>
> yep I have great results using qcache on a MyISAM production server at
> this time, and would like to do the same on the future server.
>
>> For 5.x we will fix this so that the query cache is invalidated 
>> across several servers...
>
>
> Humpf ok ... So I should not hope for 4.1.8 ... ?

For 4.1.8 I can provide you with an unsafe option, "turn it on at your 
own risk and make sure you know what you're doing"

For 5.x a _real_ solution to the problem of distributed query cache will 
be available.

>
>>
>> Olivier Kaloudoff wrote:
>>
>>> Hi,
>>>
>>>
>>>     I'm trying to improve performance for a 2 Nodes
>>> NDB based cluster, launched mysqld with --query-cache-size=32M,
>>> and did some repetitive queries, but qcache does not seems to be
>>> used..
>>
>
> (...)
>
>

Thread
qcache and 4.1.7-max officialOlivier Kaloudoff17 Nov
  • Re: qcache and 4.1.7-max officialTomas Ulin17 Nov
    • Re: qcache and 4.1.7-max officialOlivier Kaloudoff17 Nov
      • Re: qcache and 4.1.7-max officialTomas Ulin17 Nov
        • Re: qcache and 4.1.7-max officialOlivier Kaloudoff17 Nov