Re: Optimizer is not choosing index - Mailing list pgsql-performance

From Markus Innerebner
Subject Re: Optimizer is not choosing index
Date
Msg-id 74FBA69B-5697-4FDF-98A2-038BBD628126@inf.unibz.it
Whole thread Raw
In response to Re: Optimizer is not choosing index  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
Hi Tom,

thanks for your suggestion:


> Markus Innerebner <markus.innerebner@inf.unibz.it> writes:
>> The query plan says, that a sequential scan is performed on the edge table. I consider it strange that he is not
accessingon the (btree) index one the edge table. 
>
> This suggests that you have a datatype mismatch:
>
>> "  Hash Cond: ((e.target)::numeric = n.id)"
>
> Your index is presumably on e.target, not e.target::numeric, so it's not
> applicable.  Try to make the join columns the same datatype.

indeed: the id column in the node table had as type numeric, while in edges the target is integer.

After changing it, the index is used again.

many thanks


cheers Markus

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