[Koha-patches] [PATCH] BUG-2393: ENHANCEMENT: SearchMember() uses "cardnumber%" wildcard - if other search-types fail

[Joshua Ferraro]

On Thu, Jul 24, 2008 at 1:16 PM, paul POULAIN <paul.poulain at biblibre.com> wrote:
> Joe Atzberger a écrit :
>> This is a bad idea for any sizable library.  Consider a converted
>> Dynix library or any using the common 14-digit Codabar format
>> identifiers.  All patron barcodes would be "2" + 4 digit institution
>> code + 9 more digits (typically 8 incremental, 1 checksum).  A
>> truncated search would return ALL patrons for anything less than 6
>> digits.
>>
>> Let the librarian ask for a truncated search with a "%", and they can
>> have it.  Otherwise, what we really want is a zebra index with liberal
>> rules about truncation, not an SQL query that intentionally steps
>> through 50,000 patrons with 13 (or more!) LIKE clauses.
>>
>> There is no limit on the SearchMember query, and expansions of scope
>> on a common operation like this will have predictable detrimental
>> effects on performance.  While most SearchMember's problems predate
>> this patch, I think this is a step in the wrong direction.
> hehe... I should have think of that with my sample of "accepting patches
> on a stable release"... I almost got it (I asked myself the question :
> "it's still indexed", so speedy), but missed the fact we could get
> zillions of results. that proves that the more eyes are looking, the
> less bugs are staying alive ;-)
>
> Note that we also have the problem with surname search : on a large
> library, entering "A" will return all patrons with surname starting by
> 'A' or firstname starting by 'A'.
>
> So, maybe we should have a 2 step check :
> - do the search without %
> - if no answer : count the number of results with %. If less than, say
> 100 => return, if more => ??
I believe that running COUNT() will take just as long as running the query
itself, at least that's my understanding of how COUNT() works.

Cheers,

-- 
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