> >
> > I have got some expensive sql queries (doing lots of LEFT JOINS) that result
> > in anything between 10 to 10000 results. I need to do paging on those. So
> > far I have used a LIMIT solution which will not do anymore because you don't
> > get the whole total.
i just decided to issue a count query,
then use limit as the following
$count_query = "select count(*) as dict_pager_search from
".$def_table ." where word like '" . $search . "%' "; // not much worse
than an extra count query
$countResult = sql_fetch($count_query);
$max_from_db_table = $countResult[dict_pager_search];
...<snip>
then use logic to find the slice you want and create the logic
my logic was copied from DB::Pager module
then make a limit query as shown here (DB::Pager computes offsets for me
given size, which came from the count query above)
if ($debug_dict_pager) echo "------------- page offsets
---------------<br>";
$max_minArr = $pager->getOffsetByPageId();
if ($debug_dict_pager) var_dump($max_minArr);
if ($debug_dict_pager) echo "<br>";
$offset = $max_minArr[0] -1; // if it returns 1, the sql query 'offset
1' skips the first row
$upper_limit = $max_minArr[1];
$sql_limit = $upper_limit - $offset;
if ($debug_dict_pager) echo "offset = $offset<br>";
if ($debug_dict_pager) echo "limit = ". $sql_limit . "<br>";
i am ignorant as to why anybody would need 10,000 results at one time.
maybe instead of decreasing the left joins you should combine them into
a query which makes for a smaller result set. MAYBE.
well, you will only deal with sql_server load not apache_server also
using cpu.
i also am looking at server-side sql solutions now.
> > The question now is: is the serializing/unserializing more expensive than
> > another db call?
>
yes, file connection/db connection are same speed, in milliseconds, as
compared to CPU time which is nanoseconds. but you have already a
connection to the DB, just use it is inexpensive.
does php let you use shared memory to store the sessions?
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