Re: PostgreSQL Indexing versus MySQL

Lincoln Yeoh wrote:
> At 04:14 PM 2/17/2004 -0700, scott.marlowe wrote:
>>custom type (hex, foobar, etc...) from one to another.  What this means
>>too you, the user, is that:
>>
>>create table test (id int8, info text);
>><insert 10,000 rows>
>>select * from test where id=456;
>>
>>will result in a sequential scan.  Why?  Because the default integer type
>>is int4, and your id field is int8.  Cast the value to int8, and watch it
>>use an index scan:
>>
>>select * From test where id=cast(456 as int8);
>
> Actually won't
> select * from test where id='456'
> use the index?
>
> I'm curious if this work in all cases - e.g. postgresql figures the best
> cast for text to whatever, even for relevant custom types?
>

'456' is not text, it is a quoted literal of (yet) unknown type and kept
that way for long enough to know that it should be an int8, ideally.


Jan

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