| Re: Query or Array functions [message #176965 is a reply to message #176957] |
Fri, 10 February 2012 13:54   |
Scott Johnson
Messages: 196
Registered: January 2012
Karma:
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Senior Member |
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On 2/9/2012 5:39 PM, Michael Fesser wrote:
> .oO(Scott Johnson)
>
>> First off I am doing this on a back-end admin page.
>> I have a DB with lets say 5000 records and a dozen or more fields.
>>
>> On the page which will display these records I am planning on using
>> pagination to display so many records at once. So far so good.
>>
>> What i would like to do is provide a row above the table of records
>> where the user can enter text to filter the display on each column.
>>
>> I plan to use AJAX and filter as the user types which in itself is not a
>> problem.
>
> Why AJAX? Why not do it the simple way with a "refresh" button?
>
>> The problem I see is the numerous DB queries and I don't see querying
>> the DB each time the user types a letter as a practical approach. (I
>> could be wrong).
>>
>> What I was thinking of doing is loading the full record set into an
>> array and then filter out the array of the needed data as the user types.
>>
>> I have not done any intense array manipulations like this before and am
>> wondering if this seems like a practical approach.
>
> I don't think so. You still have to fetch the data from the DB whenever
> the user changes the filter. Every AJAX request to the server is just
> another HTTP request, completely independent from all others before.
>
> You can't store big data from one request and then just output parts of
> it on every coming request (unless you store all the data in a session,
> but this wouldn't make much sense here and would still cause a lot of IO
> overhead).
>
> In other words: Every request (including the ones via AJAX) causes your
> script to start from scratch again, so you have to fetch the data and
> filter it over and over again anyway. Also don't forget that after the
> user changes the filter options, the new data has to be transferred to
> the client. When there's a lot of records, this might take some time.
>
> Don't expect a real-time display and ask yourself: Do you really need
> AJAX stuff or wouldn't it be enough to use a good old-fashioned form
> with a "refresh" button?
>
> Micha
>
Thanks Micha
You bring up a great issues to the idea of accessing the data without a
separate page load. The data would need to be loaded into a session to
be accessible with subsequent calls to the server w/o calling an entire
page load.
Not sure how loading a large data set into a session would affect
performance. I know 5000 records is not all the large in the big
picture of large things but I like to 'try' to think ahead to larger issues.
But Thomas brought up a good point of data being modified after the
initial page load would not be represented any longer. So I think the
separate data scheme is not a feasible solution any longer.
Thanks
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