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From:Michael Widenius Date:November 13 1999 10:53pm
Subject:Re: mysql is a pain in the ass
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>>>>> "Frederik" == Frederik Lindberg <lindberg@stripped>
> writes:

<cut>

Frederik> I expect it's not trivial. I would expect the key to be indexed as a
Frederik> [balanced] tree. You enter at the root, and within a few comparisons,
Frederik> you're at 'foo...'. Now all others are in the branches of your node. No
Frederik> such thing for '%foo', for which you'd have to scan the entire index. For
Frederik> LIKE '%foo' I'd create an index for the inverse ('oof...'), but I don't
Frederik> know how one would optimize LIKE '%foo%'. Also, don't know the MySQL
Frederik> internals. Maybe it is very easy to speed up the index scan, or maybe
Frederik> MySQL incorrectly decides that the index is worthless (even though a
Frederik> complete index scan is cheaper than a complete data scan).

The above isn't really true;  If the records are short, it's faster to 
scan the table than scan the index (as scanning the index involves
much more seeks)

<cut> (When talking about analyzing)

>> To me, this is magic.  It may require the most massive changes to the internal
>> structure of MySQL, for all I know.  It may also be a large part of the size of
>> oracle :)

Frederik> I thought that some ISAM index optimizing commands do just that (but less
Frederik> visibly).
 
Yes, MySQL is not as big need of a analyze command as Oracle, as MySQL
can, with very low overhead, find out the key distribution from the
'live' index.

Regards,
Monty
Thread
mysql is a pain in the assMark O. Davis26 Oct
  • Re: mysql is a pain in the assEd Carp26 Oct
  • Re: mysql is a pain in the assLindsay Davies26 Oct
  • Re: mysql is a pain in the assfooler26 Oct
  • Re: mysql is a pain in the assBogdan Paduraru26 Oct
  • RE: mysql is a pain in the assDavid Moreno S.26 Oct
  • Re: mysql is a pain in the assJeremy Cole26 Oct
  • Re: mysql is a pain in the assMark Russell26 Oct
  • Re: mysql is a pain in the assMark Russell26 Oct
  • Re: mysql is a pain in the assRuben I Safir26 Oct
  • Re: mysql is a pain in the assRuben I Safir26 Oct
  • Re: mysql is a pain in the assTonu Samuel26 Oct
  • Re: mysql is a pain in the ass(Paul D. Smith)26 Oct
  • Re: mysql is a pain in the assfooler27 Oct
  • Re: mysql is a pain in the assfooler27 Oct
    • Re: mysql is a pain in the assEd Carp27 Oct
  • Re: mysql is a pain in the assfooler27 Oct
  • Re: mysql is a pain in the assfooler27 Oct
    • Re: mysql is a pain in the assEd Carp27 Oct
      • Re: mysql is a pain in the assfooler27 Oct
        • RE: mysql is a pain in the assOzlinx)27 Oct
        • Re: mysql is a pain in the assEd Carp27 Oct
          • Re: mysql is a pain in the assRuben Safir27 Oct
      • Re: mysql is a pain in the assJay J27 Oct
      • Re: mysql is a pain in the assTonu Samuel27 Oct
        • Re: mysql is a pain in the assDan Nelson27 Oct
        • Re: mysql is a pain in the assDan Nelson27 Oct
      • Re: mysql is a pain in the assfooler27 Oct
        • Re: mysql is a pain in the assJani Tolonen27 Oct
          • Priorities on the TODO list [was Re: mysql is a pain in the ass]Bob Kline27 Oct
            • MySQL and ZendStephen J. Taranto27 Oct
              • Re: MySQL and Zend(Sean McKenna)28 Oct
        • Full commercial products vs. open source [was Re: mysql is a painin the ass]Bob Kline27 Oct
        • RE: mysql is a pain in the assOzlinx)28 Oct
      • Re: mysql is a pain in the assJay J27 Oct
      • Re: mysql is a pain in the assTonu Samuel27 Oct
      • Re: mysql is a pain in the assTonu Samuel27 Oct
      • Re: mysql is a pain in the assfooler27 Oct
        • Re: mysql is a pain in the assBob Kline27 Oct
        • Re: mysql is a pain in the assRuben Safir27 Oct
        • Re: mysql is a pain in the assMike Schwartz28 Oct
          • Re: mysql is a pain in the assJani Tolonen28 Oct
            • Re: mysql is a pain in the assMike Schwartz29 Oct
              • Re: mysql is a pain in the assFrederik Lindberg29 Oct
                • Re: mysql is a pain in the assMike Schwartz29 Oct
                  • Re: mysql is a pain in the assFrederik Lindberg29 Oct
                    • Re: mysql is a pain in the assMichael Widenius14 Nov
                      • LIKE '%foo%' (was: mysql is a ...)Frederik Lindberg14 Nov
                  • Re: mysql is a pain in the assMichael Widenius14 Nov
                    • Re: mysql is a pain in the assBob Kline14 Nov
      • Re: mysql is a pain in the assTonu Samuel28 Oct
      • Re: mysql is a pain in the assfooler29 Oct
        • Hardware vs Software and the speedJani Tolonen29 Oct
      • Re: Hardware vs Software and the speedfooler29 Oct
        • Re: Hardware vs Software and the speedJani Tolonen29 Oct
      • Re: mysql is a pain in the asssasha29 Oct
      • Re: Hardware vs Software and the speedfooler30 Oct
        • Re: Hardware vs Software and the speedJani Tolonen1 Nov
      • Re: mysql is a pain in the assDuncan Kinder30 Oct
  • Re: mysql is a pain in the assSabat27 Oct
  • Re: mysql is a pain in the ass(Paul D. Smith)27 Oct
Re: mysql is a pain in the assOzlinx)26 Oct
RE: mysql is a pain in the assJohn Foley26 Oct
  • RE: mysql is a pain in the assBob Kline26 Oct
  • mysql GUI ClientBronco26 Oct
    • Re: mysql GUI Clientjurban26 Oct
Re: Hardware vs Software and the speedfooler30 Oct
  • Re: Hardware vs Software and the speedsinisa30 Oct
Re: mysql is a pain in the assJoseph R. Junkin30 Oct
  • Re: mysql is a pain in the assLarry Rufo30 Oct
    • Re: mysql is a pain in the assBlain Nelson1 Nov
  • Re: mysql is a pain in the assMike Schwartz1 Nov
Re: Hardware vs Software and the speedEd Carp1 Nov
Re: mysql is a pain in the assEd Carp1 Nov
  • Re: mysql is a pain in the assLarry Rufo2 Nov
Re: mysql is a pain in the assDejan Lekic1 Nov
Re: mysql is a pain in the assRaul Miller1 Nov
  • Re: mysql is a pain in the asssinisa2 Nov
    • Re: mysql is a pain in the assMatthias Urlichs2 Nov
    • Re: mysql is a pain in the assRaul Miller2 Nov
      • Re: mysql is a pain in the assPatrick Greenwell2 Nov
        • Re: mysql is a pain in the assRaul Miller2 Nov
          • Re: mysql is a pain in the asssinisa3 Nov
            • Re: mysql is a pain in the assRaul Miller3 Nov
              • Re: mysql is a pain in the asssinisa4 Nov
                • Re: mysql is a pain in the assRaul Miller4 Nov
              • Re: mysql is a pain in the assMichael Widenius14 Nov
                • Re: mysql is a pain in the assRaul Miller14 Nov
      • Re: mysql is a pain in the asssinisa3 Nov
        • Re: mysql is a pain in the assRaul Miller3 Nov
          • Re: mysql is a pain in the assMichael Widenius14 Nov
  • Re: mysql is a pain in the assDave Hodgkinson2 Nov
    • Re: mysql is a pain in the assRaul Miller2 Nov
Re: mysql is a pain in the assEd Carp3 Nov
  • Re: mysql is a pain in the assRaul Miller3 Nov
    • Re: mysql is a pain in the assMike Wexler3 Nov
      • Re: mysql is a pain in the assMatthias Urlichs7 Nov
        • Re: mysql is a pain in the assRaul Miller8 Nov
        • Re: mysql is a pain in the assMichael Widenius28 Nov
      • Re: mysql is a pain in the assMichael Widenius28 Nov
  • MySQL 3.23.7? (was)Re: mysql is a pain in the assVan28 Nov
    • Re: MySQL 3.23.7? (was)Re: mysql is a pain in the asssinisa28 Nov
  • Re: MySQL 3.23.7? (was)Re: mysql is a pain in the assTonu Samuel28 Nov