Re: update inside function does not use the index

On 11/16/2015 08:03 AM, Johannes wrote:

Ccing list

> No, i did a mistake while simplifying it.
>
> It should be
>
> FOR i IN SELECT id, level, path_names||'%' as path_names from x LOOP
> update x set path_ids[i.level] = i.id where path_names like i.path_names;

So what do you see if you do?:

EXPLAIN ANALYZE select ... your_function(...);

>
> Sorry.
> Best regards Johannes
>
>
> Am 16.11.2015 um 15:10 schrieb Adrian Klaver:
>> On 11/16/2015 05:56 AM, Johannes wrote:
>>> Dear List,
>>>
>>> I have problems with a self written function, which does not use the
>>> index, which takes very long (500 ms per update).
>>>
>>>
>>> The pl/pgsql function iterates over a select resultset with a cursor.
>>> In every loop I execute an update with a where LIKE condition, which
>>> relates to my current cursor position:
>>>
>>> FOR i IN SELECT id, level_ids, path_names||'%' as path_names from x LOOP
>>> update x set path_ids[i.level] = id where path_names like i.path_names;
>>
>> Is this the actual UPDATE in the function?
>>
>> If so, where are i.level and id coming from?
>>
>> Or is that supposed to be?:
>>
>> update x set path_ids[i.level_ids] = i.id where path_names like
>> i.path_names;
>>
>>> RAISE NOTICE 'path_names : %', i.path_names;
>>> END LOOP;
>>>
>>>
>>>
>>> Calling the updates outside the function, they are very fast because
>>> like 'a.b%' uses the index of the path field ( ~ 15 ms ).
>>>
>>> Does anyone know how to fix that?
>>> Thanks, Johannes
>>>
>>
>>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com