Re: grep -f keyword data query

Hello David

Thank you for replying.

2015年12月30日(水) 6:04 David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>:

> 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.
>

Could you tell me more detail about Alternatively part?

It is good idea to split host and part.
I'll try it.

My matching pattern is the following
1, http://www.yahoo.com/a/b/% (host equal, path like)
2, http://%.yahoo.com/a/b/% (host and path like )

Can I use equality operator in those cases?

Best regards.

>
> --
> David Rowley http://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Training & Services
>