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From:谢立超 Date:January 9 2011 3:00pm
Subject:Optimization about count(*)
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sql:
select count(*) from t where id > 10 and id < 1000000;
In table t, there is an B-tree index on id field, this sql will read
hundreds of thousandes of lines from the storage engine, this is a
time-consuming operation.
If tell the storage engine computing the count in the range, does it
have higher performance? (using records_in_range() api and so on)
Thread
Optimization about count(*)谢立超9 Jan
  • Re: Optimization about count(*)Sergei Golubchik9 Jan
    • Re: Optimization about count(*)sky.jian10 Jan
      • Re: Optimization about count(*)Sergei Golubchik10 Jan