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Thread: help with query

help with query

From
Dave Cramer
Date:
RT uses a query like:

SELECT distinct main.oid,main.* FROM Tickets main
WHERE
(main.EffectiveId = main.id)
AND
(main.Status != 'deleted')
AND
    ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
AND
    ( (main.Queue = '9') )
AND ((
        ( (Links.Type = 'MemberOf') AND (Links.LocalTarget = '17417') AND (main.id = Links.LocalBase) )
      OR
        ( (Links.Type = 'MemberOf') AND (Links.LocalBase = '17417') AND (main.id = Links.LocalTarget) )
      or
        (main.id = '17417')
     )
  );


which produces a query plan:

Nested Loop  (cost=0.00..813.88 rows=1 width=169)
   Join Filter: (((("inner"."type")::text = 'MemberOf'::text) OR ("outer".id = 17417)) AND (("inner".localbase = 17417)
OR(("inner"."type")::text = 'MemberOf'::text) OR ("outer".id 
= 17417)) AND (("outer".id = "inner".localtarget) OR (("inner"."type")::text = 'MemberOf'::text) OR ("outer".id =
17417))AND ((("inner"."type")::text = 'MemberOf'::text) OR ("inner" 
.localtarget = 17417) OR ("outer".id = 17417)) AND (("inner".localbase = 17417) OR ("inner".localtarget = 17417) OR
("outer".id= 17417)) AND (("outer".id = "inner".localtarget) OR ( 
"inner".localtarget = 17417) OR ("outer".id = 17417)) AND ((("inner"."type")::text = 'MemberOf'::text) OR ("outer".id =
"inner".localbase)OR ("outer".id = 17417)) AND (("inner".loca 
lbase = 17417) OR ("outer".id = "inner".localbase) OR ("outer".id = 17417)) AND (("outer".id = "inner".localtarget) OR
("outer".id= "inner".localbase) OR ("outer".id = 17417))) 
   ->  Index Scan using tickets1 on tickets main  (cost=0.00..657.61 rows=1 width=169)
         Index Cond: (queue = 9)
         Filter: ((effectiveid = id) AND ((status)::text <> 'deleted'::text) AND ((("type")::text = 'ticket'::text) OR
(("type")::text= 'subticket'::text))) 
   ->  Seq Scan on links  (cost=0.00..46.62 rows=1462 width=20)

If I rewrite the query as:

SELECT main.* FROM Tickets main
WHERE
(main.EffectiveId = main.id)
AND
(main.Status != 'deleted')
AND
    ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
AND
    ( (main.Queue = '9') )
AND (
        17417 in (select links.localtarget from links where links.type='MemberOf' and main.id=links.localbase)
        or
        17417 in ( select links.localbase from links where links.type='MemberOf' and main.id=links.localtarget)
      or
        main.id = '17417'
    )
  ;

The time for the query goes from 1500ms to 15ms. The two OR clauses

        ( (Links.Type = 'MemberOf') AND (Links.LocalTarget = '17417') AND (main.id = Links.LocalBase) )
      OR
        ( (Links.Type = 'MemberOf') AND (Links.LocalBase = '17417') AND (main.id = Links.LocalTarget) )

don't contribute to the result set in this particular dataset, which is why the speed increases so dramatically.

Is there a way to rewrite the top query to get the same results? I have already talked to Best Practical,
and subqueries are not easily embraced.

Dave
--
Dave Cramer
519 939 0336
ICQ # 14675561

Re: help with query

From
Brad Bulger
Date:
You're doing a join except not, is the trouble, looks like. The query is really
"FROM Tickets main, Links", but when Tickets.id is 17417, you've got no join
to the Links table. So you end up getting every row in Links for each row in
Tickets with id = 17417.

I'd think this wants to be two queries or a union:

SELECT distinct main.oid,main.* FROM Tickets main
WHERE (main.EffectiveId = main.id)
AND (main.Status != 'deleted')
AND ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
AND ( (main.Queue = '9') )
AND ( (main.id = '17417'))
union
SELECT distinct main.oid,main.* FROM Tickets main, Links
WHERE (main.EffectiveId = main.id)
AND (main.Status != 'deleted')
AND ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
AND ( (main.Queue = '9') )
AND ( (Links.Type = 'MemberOf') )
AND ( (Links.LocalTarget = '17417') )
AND ( (main.id = Links.LocalBase) ) OR (main.id = Links.LocalTarget) )
;

or else, yah, a subquery:

[...]
AND (
  main.id = '17417'
  or
  exists(
    select true from Links
    where Type = 'MemberOf' and LocalTarget = '17417'
     and (LocalBase = main.id or LocalTarget = main.id)
  )
)

Those are the only things I can think of to make it work, anyways.

Dave Cramer wrote:

> RT uses a query like:
>
> SELECT distinct main.oid,main.* FROM Tickets main
> WHERE
> (main.EffectiveId = main.id)
> AND
> (main.Status != 'deleted')
> AND
>     ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
> AND
>     ( (main.Queue = '9') )
> AND ((
>         ( (Links.Type = 'MemberOf') AND (Links.LocalTarget = '17417') AND (main.id = Links.LocalBase) )
>       OR
>         ( (Links.Type = 'MemberOf') AND (Links.LocalBase = '17417') AND (main.id = Links.LocalTarget) )
>       or
>         (main.id = '17417')
>      )
>   );
>
>
> which produces a query plan:
>
> Nested Loop  (cost=0.00..813.88 rows=1 width=169)
>    Join Filter: (((("inner"."type")::text = 'MemberOf'::text) OR ("outer".id = 17417)) AND (("inner".localbase =
17417)OR (("inner"."type")::text = 'MemberOf'::text) OR ("outer".id 
> = 17417)) AND (("outer".id = "inner".localtarget) OR (("inner"."type")::text = 'MemberOf'::text) OR ("outer".id =
17417))AND ((("inner"."type")::text = 'MemberOf'::text) OR ("inner" 
> .localtarget = 17417) OR ("outer".id = 17417)) AND (("inner".localbase = 17417) OR ("inner".localtarget = 17417) OR
("outer".id= 17417)) AND (("outer".id = "inner".localtarget) OR ( 
> "inner".localtarget = 17417) OR ("outer".id = 17417)) AND ((("inner"."type")::text = 'MemberOf'::text) OR ("outer".id
="inner".localbase) OR ("outer".id = 17417)) AND (("inner".loca 
> lbase = 17417) OR ("outer".id = "inner".localbase) OR ("outer".id = 17417)) AND (("outer".id = "inner".localtarget)
OR("outer".id = "inner".localbase) OR ("outer".id = 17417))) 
>    ->  Index Scan using tickets1 on tickets main  (cost=0.00..657.61 rows=1 width=169)
>          Index Cond: (queue = 9)
>          Filter: ((effectiveid = id) AND ((status)::text <> 'deleted'::text) AND ((("type")::text = 'ticket'::text)
OR(("type")::text = 'subticket'::text))) 
>    ->  Seq Scan on links  (cost=0.00..46.62 rows=1462 width=20)
>
> If I rewrite the query as:
>
> SELECT main.* FROM Tickets main
> WHERE
> (main.EffectiveId = main.id)
> AND
> (main.Status != 'deleted')
> AND
>     ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
> AND
>     ( (main.Queue = '9') )
> AND (
>         17417 in (select links.localtarget from links where links.type='MemberOf' and main.id=links.localbase)
>         or
>         17417 in ( select links.localbase from links where links.type='MemberOf' and main.id=links.localtarget)
>       or
>         main.id = '17417'
>     )
>   ;
>
> The time for the query goes from 1500ms to 15ms. The two OR clauses
>
>         ( (Links.Type = 'MemberOf') AND (Links.LocalTarget = '17417') AND (main.id = Links.LocalBase) )
>       OR
>         ( (Links.Type = 'MemberOf') AND (Links.LocalBase = '17417') AND (main.id = Links.LocalTarget) )
>
> don't contribute to the result set in this particular dataset, which is why the speed increases so dramatically.
>
> Is there a way to rewrite the top query to get the same results? I have already talked to Best Practical,
> and subqueries are not easily embraced.
>
> Dave

Re: help with query

From
Dave Cramer
Date:
Brad,

Thanks, that runs on the same order of magnitude as the subqueries.

DAve
On Thu, 2004-08-19 at 09:38, Brad Bulger wrote:
> You're doing a join except not, is the trouble, looks like. The query is really
> "FROM Tickets main, Links", but when Tickets.id is 17417, you've got no join
> to the Links table. So you end up getting every row in Links for each row in
> Tickets with id = 17417.
>
> I'd think this wants to be two queries or a union:
>
> SELECT distinct main.oid,main.* FROM Tickets main
> WHERE (main.EffectiveId = main.id)
> AND (main.Status != 'deleted')
> AND ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
> AND ( (main.Queue = '9') )
> AND ( (main.id = '17417'))
> union
> SELECT distinct main.oid,main.* FROM Tickets main, Links
> WHERE (main.EffectiveId = main.id)
> AND (main.Status != 'deleted')
> AND ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
> AND ( (main.Queue = '9') )
> AND ( (Links.Type = 'MemberOf') )
> AND ( (Links.LocalTarget = '17417') )
> AND ( (main.id = Links.LocalBase) ) OR (main.id = Links.LocalTarget) )
> ;
>
> or else, yah, a subquery:
>
> [...]
> AND (
>   main.id = '17417'
>   or
>   exists(
>     select true from Links
>     where Type = 'MemberOf' and LocalTarget = '17417'
>      and (LocalBase = main.id or LocalTarget = main.id)
>   )
> )
>
> Those are the only things I can think of to make it work, anyways.
>
> Dave Cramer wrote:
>
> > RT uses a query like:
> >
> > SELECT distinct main.oid,main.* FROM Tickets main
> > WHERE
> > (main.EffectiveId = main.id)
> > AND
> > (main.Status != 'deleted')
> > AND
> >     ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
> > AND
> >     ( (main.Queue = '9') )
> > AND ((
> >         ( (Links.Type = 'MemberOf') AND (Links.LocalTarget = '17417') AND (main.id = Links.LocalBase) )
> >       OR
> >         ( (Links.Type = 'MemberOf') AND (Links.LocalBase = '17417') AND (main.id = Links.LocalTarget) )
> >       or
> >         (main.id = '17417')
> >      )
> >   );
> >
> >
> > which produces a query plan:
> >
> > Nested Loop  (cost=0.00..813.88 rows=1 width=169)
> >    Join Filter: (((("inner"."type")::text = 'MemberOf'::text) OR ("outer".id = 17417)) AND (("inner".localbase =
17417)OR (("inner"."type")::text = 'MemberOf'::text) OR ("outer".id 
> > = 17417)) AND (("outer".id = "inner".localtarget) OR (("inner"."type")::text = 'MemberOf'::text) OR ("outer".id =
17417))AND ((("inner"."type")::text = 'MemberOf'::text) OR ("inner" 
> > .localtarget = 17417) OR ("outer".id = 17417)) AND (("inner".localbase = 17417) OR ("inner".localtarget = 17417) OR
("outer".id= 17417)) AND (("outer".id = "inner".localtarget) OR ( 
> > "inner".localtarget = 17417) OR ("outer".id = 17417)) AND ((("inner"."type")::text = 'MemberOf'::text) OR
("outer".id= "inner".localbase) OR ("outer".id = 17417)) AND (("inner".loca 
> > lbase = 17417) OR ("outer".id = "inner".localbase) OR ("outer".id = 17417)) AND (("outer".id = "inner".localtarget)
OR("outer".id = "inner".localbase) OR ("outer".id = 17417))) 
> >    ->  Index Scan using tickets1 on tickets main  (cost=0.00..657.61 rows=1 width=169)
> >          Index Cond: (queue = 9)
> >          Filter: ((effectiveid = id) AND ((status)::text <> 'deleted'::text) AND ((("type")::text = 'ticket'::text)
OR(("type")::text = 'subticket'::text))) 
> >    ->  Seq Scan on links  (cost=0.00..46.62 rows=1462 width=20)
> >
> > If I rewrite the query as:
> >
> > SELECT main.* FROM Tickets main
> > WHERE
> > (main.EffectiveId = main.id)
> > AND
> > (main.Status != 'deleted')
> > AND
> >     ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
> > AND
> >     ( (main.Queue = '9') )
> > AND (
> >         17417 in (select links.localtarget from links where links.type='MemberOf' and main.id=links.localbase)
> >         or
> >         17417 in ( select links.localbase from links where links.type='MemberOf' and main.id=links.localtarget)
> >       or
> >         main.id = '17417'
> >     )
> >   ;
> >
> > The time for the query goes from 1500ms to 15ms. The two OR clauses
> >
> >         ( (Links.Type = 'MemberOf') AND (Links.LocalTarget = '17417') AND (main.id = Links.LocalBase) )
> >       OR
> >         ( (Links.Type = 'MemberOf') AND (Links.LocalBase = '17417') AND (main.id = Links.LocalTarget) )
> >
> > don't contribute to the result set in this particular dataset, which is why the speed increases so dramatically.
> >
> > Is there a way to rewrite the top query to get the same results? I have already talked to Best Practical,
> > and subqueries are not easily embraced.
> >
> > Dave
>
--
Dave Cramer
519 939 0336
ICQ # 14675561

Re: help with query

From
Dave Cramer
Date:
From what I can figure, queries like this run much quicker on other
databases, is this something that can be improved ?

Dave
On Thu, 2004-08-19 at 09:38, Brad Bulger wrote:
> You're doing a join except not, is the trouble, looks like. The query is really
> "FROM Tickets main, Links", but when Tickets.id is 17417, you've got no join
> to the Links table. So you end up getting every row in Links for each row in
> Tickets with id = 17417.
>
> I'd think this wants to be two queries or a union:
>
> SELECT distinct main.oid,main.* FROM Tickets main
> WHERE (main.EffectiveId = main.id)
> AND (main.Status != 'deleted')
> AND ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
> AND ( (main.Queue = '9') )
> AND ( (main.id = '17417'))
> union
> SELECT distinct main.oid,main.* FROM Tickets main, Links
> WHERE (main.EffectiveId = main.id)
> AND (main.Status != 'deleted')
> AND ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
> AND ( (main.Queue = '9') )
> AND ( (Links.Type = 'MemberOf') )
> AND ( (Links.LocalTarget = '17417') )
> AND ( (main.id = Links.LocalBase) ) OR (main.id = Links.LocalTarget) )
> ;
>
> or else, yah, a subquery:
>
> [...]
> AND (
>   main.id = '17417'
>   or
>   exists(
>     select true from Links
>     where Type = 'MemberOf' and LocalTarget = '17417'
>      and (LocalBase = main.id or LocalTarget = main.id)
>   )
> )
>
> Those are the only things I can think of to make it work, anyways.
>
> Dave Cramer wrote:
>
> > RT uses a query like:
> >
> > SELECT distinct main.oid,main.* FROM Tickets main
> > WHERE
> > (main.EffectiveId = main.id)
> > AND
> > (main.Status != 'deleted')
> > AND
> >     ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
> > AND
> >     ( (main.Queue = '9') )
> > AND ((
> >         ( (Links.Type = 'MemberOf') AND (Links.LocalTarget = '17417') AND (main.id = Links.LocalBase) )
> >       OR
> >         ( (Links.Type = 'MemberOf') AND (Links.LocalBase = '17417') AND (main.id = Links.LocalTarget) )
> >       or
> >         (main.id = '17417')
> >      )
> >   );
> >
> >
> > which produces a query plan:
> >
> > Nested Loop  (cost=0.00..813.88 rows=1 width=169)
> >    Join Filter: (((("inner"."type")::text = 'MemberOf'::text) OR ("outer".id = 17417)) AND (("inner".localbase =
17417)OR (("inner"."type")::text = 'MemberOf'::text) OR ("outer".id 
> > = 17417)) AND (("outer".id = "inner".localtarget) OR (("inner"."type")::text = 'MemberOf'::text) OR ("outer".id =
17417))AND ((("inner"."type")::text = 'MemberOf'::text) OR ("inner" 
> > .localtarget = 17417) OR ("outer".id = 17417)) AND (("inner".localbase = 17417) OR ("inner".localtarget = 17417) OR
("outer".id= 17417)) AND (("outer".id = "inner".localtarget) OR ( 
> > "inner".localtarget = 17417) OR ("outer".id = 17417)) AND ((("inner"."type")::text = 'MemberOf'::text) OR
("outer".id= "inner".localbase) OR ("outer".id = 17417)) AND (("inner".loca 
> > lbase = 17417) OR ("outer".id = "inner".localbase) OR ("outer".id = 17417)) AND (("outer".id = "inner".localtarget)
OR("outer".id = "inner".localbase) OR ("outer".id = 17417))) 
> >    ->  Index Scan using tickets1 on tickets main  (cost=0.00..657.61 rows=1 width=169)
> >          Index Cond: (queue = 9)
> >          Filter: ((effectiveid = id) AND ((status)::text <> 'deleted'::text) AND ((("type")::text = 'ticket'::text)
OR(("type")::text = 'subticket'::text))) 
> >    ->  Seq Scan on links  (cost=0.00..46.62 rows=1462 width=20)
> >
> > If I rewrite the query as:
> >
> > SELECT main.* FROM Tickets main
> > WHERE
> > (main.EffectiveId = main.id)
> > AND
> > (main.Status != 'deleted')
> > AND
> >     ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
> > AND
> >     ( (main.Queue = '9') )
> > AND (
> >         17417 in (select links.localtarget from links where links.type='MemberOf' and main.id=links.localbase)
> >         or
> >         17417 in ( select links.localbase from links where links.type='MemberOf' and main.id=links.localtarget)
> >       or
> >         main.id = '17417'
> >     )
> >   ;
> >
> > The time for the query goes from 1500ms to 15ms. The two OR clauses
> >
> >         ( (Links.Type = 'MemberOf') AND (Links.LocalTarget = '17417') AND (main.id = Links.LocalBase) )
> >       OR
> >         ( (Links.Type = 'MemberOf') AND (Links.LocalBase = '17417') AND (main.id = Links.LocalTarget) )
> >
> > don't contribute to the result set in this particular dataset, which is why the speed increases so dramatically.
> >
> > Is there a way to rewrite the top query to get the same results? I have already talked to Best Practical,
> > and subqueries are not easily embraced.
> >
> > Dave
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
>       subscribe-nomail command to majordomo@postgresql.org so that your
>       message can get through to the mailing list cleanly
>
--
Dave Cramer
519 939 0336
ICQ # 14675561

Re: help with query

From
Jean-Luc Lachance
Date:
how about:

SELECT distinct main.oid,main.* FROM Tickets main
WHERE main.EffectiveId = main.id
AND main.Status != 'deleted'
AND ( main.Type = 'ticket' OR main.Type = 'subticket' )
AND ( main.Queue = '9' )
AND ( main.id = '17417'
   OR main.id IN (
     SELECT DISTINCT LocalTarget from Links
     where Type = 'MemberOf' and LocalTarget = '17417')
   OR main.id IN (
     SELECT DISTINCT LocalBase from Links
     where Type = 'MemberOf' and LocalTarget = '17417'))




Dave Cramer wrote:

> Brad,
>
> Thanks, that runs on the same order of magnitude as the subqueries.
>
> DAve
> On Thu, 2004-08-19 at 09:38, Brad Bulger wrote:
>
>>You're doing a join except not, is the trouble, looks like. The query is really
>>"FROM Tickets main, Links", but when Tickets.id is 17417, you've got no join
>>to the Links table. So you end up getting every row in Links for each row in
>>Tickets with id = 17417.
>>
>>I'd think this wants to be two queries or a union:
>>
>>SELECT distinct main.oid,main.* FROM Tickets main
>>WHERE (main.EffectiveId = main.id)
>>AND (main.Status != 'deleted')
>>AND ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
>>AND ( (main.Queue = '9') )
>>AND ( (main.id = '17417'))
>>union
>>SELECT distinct main.oid,main.* FROM Tickets main, Links
>>WHERE (main.EffectiveId = main.id)
>>AND (main.Status != 'deleted')
>>AND ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
>>AND ( (main.Queue = '9') )
>>AND ( (Links.Type = 'MemberOf') )
>>AND ( (Links.LocalTarget = '17417') )
>>AND ( (main.id = Links.LocalBase) ) OR (main.id = Links.LocalTarget) )
>>;
>>
>>or else, yah, a subquery:
>>
>>[...]
>>AND (
>>  main.id = '17417'
>>  or
>>  exists(
>>    select true from Links
>>    where Type = 'MemberOf' and LocalTarget = '17417'
>>     and (LocalBase = main.id or LocalTarget = main.id)
>>  )
>>)
>>
>>Those are the only things I can think of to make it work, anyways.
>>
>>Dave Cramer wrote:
>>
>>
>>>RT uses a query like:
>>>
>>>SELECT distinct main.oid,main.* FROM Tickets main
>>>WHERE
>>>(main.EffectiveId = main.id)
>>>AND
>>>(main.Status != 'deleted')
>>>AND
>>>    ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
>>>AND
>>>    ( (main.Queue = '9') )
>>>AND ((
>>>        ( (Links.Type = 'MemberOf') AND (Links.LocalTarget = '17417') AND (main.id = Links.LocalBase) )
>>>      OR
>>>        ( (Links.Type = 'MemberOf') AND (Links.LocalBase = '17417') AND (main.id = Links.LocalTarget) )
>>>      or
>>>        (main.id = '17417')
>>>     )
>>>  );
>>>
>>>
>>>which produces a query plan:
>>>
>>>Nested Loop  (cost=0.00..813.88 rows=1 width=169)
>>>   Join Filter: (((("inner"."type")::text = 'MemberOf'::text) OR ("outer".id = 17417)) AND (("inner".localbase =
17417)OR (("inner"."type")::text = 'MemberOf'::text) OR ("outer".id 
>>>= 17417)) AND (("outer".id = "inner".localtarget) OR (("inner"."type")::text = 'MemberOf'::text) OR ("outer".id =
17417))AND ((("inner"."type")::text = 'MemberOf'::text) OR ("inner" 
>>>.localtarget = 17417) OR ("outer".id = 17417)) AND (("inner".localbase = 17417) OR ("inner".localtarget = 17417) OR
("outer".id= 17417)) AND (("outer".id = "inner".localtarget) OR ( 
>>>"inner".localtarget = 17417) OR ("outer".id = 17417)) AND ((("inner"."type")::text = 'MemberOf'::text) OR
("outer".id= "inner".localbase) OR ("outer".id = 17417)) AND (("inner".loca 
>>>lbase = 17417) OR ("outer".id = "inner".localbase) OR ("outer".id = 17417)) AND (("outer".id = "inner".localtarget)
OR("outer".id = "inner".localbase) OR ("outer".id = 17417))) 
>>>   ->  Index Scan using tickets1 on tickets main  (cost=0.00..657.61 rows=1 width=169)
>>>         Index Cond: (queue = 9)
>>>         Filter: ((effectiveid = id) AND ((status)::text <> 'deleted'::text) AND ((("type")::text = 'ticket'::text)
OR(("type")::text = 'subticket'::text))) 
>>>   ->  Seq Scan on links  (cost=0.00..46.62 rows=1462 width=20)
>>>
>>>If I rewrite the query as:
>>>
>>>SELECT main.* FROM Tickets main
>>>WHERE
>>>(main.EffectiveId = main.id)
>>>AND
>>>(main.Status != 'deleted')
>>>AND
>>>    ( (main.Type = 'ticket') OR (main.Type = 'subticket') )
>>>AND
>>>    ( (main.Queue = '9') )
>>>AND (
>>>        17417 in (select links.localtarget from links where links.type='MemberOf' and main.id=links.localbase)
>>>        or
>>>        17417 in ( select links.localbase from links where links.type='MemberOf' and main.id=links.localtarget)
>>>      or
>>>        main.id = '17417'
>>>    )
>>>  ;
>>>
>>>The time for the query goes from 1500ms to 15ms. The two OR clauses
>>>
>>>        ( (Links.Type = 'MemberOf') AND (Links.LocalTarget = '17417') AND (main.id = Links.LocalBase) )
>>>      OR
>>>        ( (Links.Type = 'MemberOf') AND (Links.LocalBase = '17417') AND (main.id = Links.LocalTarget) )
>>>
>>>don't contribute to the result set in this particular dataset, which is why the speed increases so dramatically.
>>>
>>>Is there a way to rewrite the top query to get the same results? I have already talked to Best Practical,
>>>and subqueries are not easily embraced.
>>>
>>>Dave
>>