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From:Michael Widenius Date:January 4 2000 6:26pm
Subject:Re: I need more speed...
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>>>>> "Rick" == Rick Moore <rick@stripped> writes:

Rick> Hi Monty!  <snip>

>> FreeBSD has also some problems with mutexs handling and will easily
>> do a full context switch if two threads hits the same mutex at the
>> same time (which gets ever more likely as you get more threads).
>> One way to fix this would be to introduce 'fast' mutex that lets a
>> thread steal a mutex if no-one has the mutex, even if someone is
>> waiting for it.  This could give you a boost of 10-30 % on FreeBSD,
>> as FreeBSD has very slow context switch handling!

Rick> I'll never have more than 15 threads.

Rick> Sounds great; are you proposing a MySQL code change, or is this
Rick> an existing compile or tuning option?  In other words, is there
Rick> something I can do?

No, this is something that has to be done in the FreeBSD thread
package.  If some FreeBSD developer wants to talk to me about adding a
very fast mutex, feel free to drop me a line.

>> I don't want to start a WAR here, but it would be really
>> interesting to know how Linux would work in your situation; FreeBSD
>> may be faster in handling disks, but Linux should be better to
>> context switch.  I don't really know which thing is more important
>> for you :( (Linux is much better than FreeBSD on handling multiple
>> CPU:s, but at least for the moment the CPU doesn't seem to be your
>> bottleneck.)

Rick> Funny you should mention it.  I did switch to Linux for the past
Rick> month, but I didn't run any serious benchmarks.  Sorry.

Ouch:)  It would have been very interesting to know the difference in
your setup :(

Rick> I can say this: For my application, MySQL is more stable on
Rick> FreeBSD 3.4 than it was on RedHat Linux 6.?, plus I get a
Rick> time-tested 64bit file system.  I wish it supported kernel
Rick> threads for SMP, but oh well.  Linux certainly has an advantage
Rick> in that respect.  Both are great OS's though.

I agree.

>> Another issue, have you taken a look at the HEAP tables in 3.23 ?
>> Can you have any use of these?

Rick> Yep, I use one to cache info out of a very slow query so I don't
Rick> need to execute it very often.  Works great!

Rick> There is another possibility, but it involves massive changes in
Rick> code and I most certainly would need to get more RAM before
Rick> trying it: I might be able to create "mini-tables" on the heap,
Rick> and then merge them into the main table on a periodic basis.
Rick> Off the top of my head, it would cause 50% more queries, but 66%
Rick> would be on the heap.  I'd cut the queries to the disk table in
Rick> half with the exception of some kind of occasional INSERT ...
Rick> SELECT.

INSERT should work good on MySQL 3.23, as long as you don't do a
deletes on this table;  While MySQL fils in 'wholes' for old deleted
rows, it can't use concurrent inserts.

Rick> I need to give this more thought.

Regards,
Monty
Thread
I need more speed...Rick Moore3 Jan
  • Re: I need more speed...Tonu Samuel3 Jan
  • Re: I need more speed...Rick Moore3 Jan
  • Re: I need more speed...Tonu Samuel3 Jan
  • Re: I need more speed...Rick Moore3 Jan
    • Re: I need more speed...Dan Nelson3 Jan
    • Re: I need more speed...Benjamin Pflugmann3 Jan
    • Re: I need more speed...Michael Widenius4 Jan
      • RE: I need more speed...Steven Roussey5 Jan
        • Re: I need more speed...Benjamin Pflugmann5 Jan
          • RE: I need more speed...Steven Roussey5 Jan
            • Re: I need more speed...Benjamin Pflugmann5 Jan
          • RE: I need more speed...Steven Roussey5 Jan
            • Re: I need more speed...Benjamin Pflugmann5 Jan
            • RE: I need more speed...Michael Widenius5 Jan
              • RE: I need more speed...Steven Roussey6 Jan
                • OT: IP to Geographic areaCheng-Wei Cheng6 Jan
                  • RE: IP to Geographic areaJohn Zook6 Jan
  • Re: I need more speed...Sasha Pachev3 Jan
  • Re: I need more speed...Rick Moore3 Jan
  • Re: I need more speed...Tonu Samuel3 Jan
  • Re: I need more speed...Tonu Samuel3 Jan
    • LDAP package with mysql backendClickAgents4 Jan
      • Re: LDAP package with mysql backendRob McMillin4 Jan
      • LDAP package with mysql backendMichael Widenius4 Jan
        • Re: LDAP package with mysql backendChristopher E. Brown4 Jan
          • RE: LDAP package with mysql backendClickAgents4 Jan
            • RE: LDAP package with mysql backendChristopher E. Brown4 Jan
  • Re: I need more speed...Sasha Pachev4 Jan
    • Re: I need more speed...Michael Widenius4 Jan
      • how to..ClickAgents4 Jan
        • Re: how to..Benjamin Pflugmann4 Jan
  • Re: I need more speed...Rick Moore4 Jan
    • Re: I need more speed...Michael Widenius4 Jan
  • Re: As per your request; Re: I need more speed...Tonu Samuel5 Jan
  • Re: As per your request; Re: I need more speed...Rick Moore5 Jan
  • Re: As per your request; Re: I need more speed...Tonu Samuel5 Jan
    • FULL Text Indexjpabuyer5 Jan
      • Re: FULL Text IndexMark Zieg5 Jan
        • Re: FULL Text Indexjpabuyer5 Jan
      • RE: FULL Text IndexDan Ray5 Jan
        • RE: FULL Text Indexjpabuyer5 Jan
Re: I need more speed...Andy4 Jan
  • Re: I need more speed...Christopher E. Brown5 Jan
  • Re: I need more speed...Tonu Samuel5 Jan
Re: I need more speed...Andy4 Jan
  • Re: I need more speed...Michael Widenius4 Jan
    • Error: 2002 Can't connect to mysql using socket (111)Cheng-Wei Cheng5 Jan
      • Re: Error: 2002 Can't connect to mysql using socket (111)Sasha Pachev5 Jan