Re: [SQL] abusing an aggregate funct - Mailing list pgsql-sql

From Marc Howard Zuckman
Subject Re: [SQL] abusing an aggregate funct
Date
Msg-id Pine.LNX.4.02A.9811140953190.6343-100000@fallon.classyad.com
Whole thread Raw
In response to abusing an aggregate funct  (Thomas Good <tomg@admin.nrnet.org>)
Responses Re: [SQL] abusing an aggregate funct
Re: [SQL] abusing an aggregate funct
List pgsql-sql
On Sat, 14 Nov 1998, Thomas Good wrote:

> Due to the sheer girth of the table the following query, called from
> a data entry script,  takes a bit of time to finish:
>
> SELECT max(rec_num) FROM crtrd1;
>
> I use this to setup `rec_num + 1' for my query number (p_key)...any
> way I can speed this up a bit?  I've run vacuum analyze but the
> table size is doing me in...
>
Use a sequence to generate rec_num.  See man create_sequence.

You can then use curval('sequence_name') to get the last
sequence number generated, or if you are performing an insert:
  insert into crtrd1 (p_key,otherdata) values (nextval('sequence_name',moredata);

You could also create the table using nextval as the default
value of p_key.  You may wish to create a unique_index on
p_key, but nextval is guaranteed not to generate duplicates
unless you allow it to rollover.





Marc Zuckman
marc@fallon.classyad.com

_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
_     Visit The Home and Condo MarketPlace              _
_          http://www.ClassyAd.com                  _
_                                  _
_  FREE basic property listings/advertisements and searches.  _
_                                  _
_  Try our premium, yet inexpensive services for a real          _
_   selling or buying edge!                      _
_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_


pgsql-sql by date:

Previous
From: Thomas Good
Date:
Subject: abusing an aggregate funct
Next
From: Herouth Maoz
Date:
Subject: Re: [SQL] Some questions