Re: grep -f keyword data query

On 30 December 2015 at 04:21, Hiroyuki Sato <hiroysato(at)gmail(dot)com> wrote:

> 2015年12月29日(火) 4:35 Jeff Janes <jeff(dot)janes(at)gmail(dot)com>:
>
>>
>>
>
>> But, the planner refuses to use this index for your query anyway,
>> because it can't see that the patterns are all left-anchored.
>>
>> Really, your best bet is refactor your url data so it is stored with a
>> url_prefix and url_suffix column. Then you can do exact matching
>> rather than pattern matching.
>>
>
> I see, exact matching faster than pattern matting.
> But I need pattern match in path part
> (ie, http://www.yahoo.com/a/b/c/... )
> I would like to pattern match '/a/b/c' part.
>

If your pattern matching is as simple as that, then why not split the
/a/b/c/ part out as mentioned by Jeff? Alternatively you could just write a
function which splits that out for you and returns it, then index that
function, and then just include a call to that function in the join
condition matching with the equality operator. That'll allow hash and merge
joins to be possible again.

--
David Rowley http://www.2ndQuadrant.com/
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