Re: Queries take forever on ported database from MSSQL -> Postgresql (SOLVED)

> Is it possible that you are being bitten by the data type promotion
> issues?  Eg, if you have an indexed int2 column, and a query like
>
> select * from foo where int2col = 45;
>
> the "45" will be treated as an int4 and the index won't be used.
> Changing the WHERE clause to "where int2col = '45'" will use the
> index.

Doug you're my hero. This is kind of what was happening, but not for the
reasons you specified.

When pgAdmin's migration wizard imported all the data, it converted all
int4 fields in the MS-SQL database to int8's, however ALL the primary
keys where kept as int4 fields.

Whenever it came to do a join, it obviously did not use any indexes
since it was always joining on int8 to int4 fields. I reimported the
entire db making altering the int4 type maps int8s which STILL left the
primary keys as int4s and the rest as int8s, so I then did the whole
thing yet again and this time changed all of them to int4s.

Queries are now running faster than they are on the old box (bar the
obviously slow initial execution of a query whilst it loads indexes etc
to memory), and all using indexes as they should be.

Glad after all this it wasn't a glaring error on my part, and what might
be an issue with the migration wizard.


Yours Unwhettedly,
Robert John Shepherd.

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