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From:Christofer Dutz Date:September 21 2005 4:05pm
Subject:Bad MySQL performance with LEFT JOINS in combination with BIGINT(16)
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Hi,

I just ran into a very strange problem. I have two simple tables with 
BIGINT(16) PKs. The primary table has 7500 records and the secondars has 
15000. If I execute:

SELECT * FROM lad JOIN snd ON lad.id = snd.lad_id

The query takes 8 seconds. If I execute this one:

SELECT * FROM lad LEFT JOIN snd ON lad.id = snd.lad_id

I quit the query after 5 minutes.

Why is this so?

Chritofer Dutz
Thread
Bad MySQL performance with LEFT JOINS in combination with BIGINT(16)KeysChristofer Dutz21 Sep
  • Re: Bad MySQL performance with LEFT JOINS in combination with BIGINT(16)KeysDevananda21 Sep
    • Re: Bad MySQL performance with LEFT JOINS in combination with BIGINT(16)KeysChristofer Dutz21 Sep
      • Re: Bad MySQL performance with LEFT JOINS in combination with BIGINT(16)KeysAlexey Polyakov21 Sep