Thread

1. Re: Indexes

   Tom Lane <tgl@sss.pgh.pa.us> — 2004-08-20T03:16:32Z

   Primoz <primoz@slo-tech.com> writes:
   > is there any way to speedup queryes like
   
   > select ... from [table a] where [int field b] = [number] order by [datetime 
   > field c] desc limit [number];
   
   For reasonably-small values of the LIMIT, what you want is
   	(a) a two-column index on (b,c)
   	(b) change the ORDER BY to
   		ORDER BY b DESC, c DESC
   
   See the pgsql-performance archives for more discussion.
   
   			regards, tom lane
   
   

2. Indexes

   Primoz <primoz@slo-tech.com> — 2004-08-20T03:31:36Z

   Hello,
   
   is there any way to speedup queryes like
   
   select ... from [table a] where [int field b] = [number] order by [datetime 
   field c] desc limit [number];
   
   with index on field b I get something, but pgsql afterwards resolves to 
   sorting manually. 
   
   partial indices with index on field c where field b = number works, but are 
   dirty and are becoming annoying as number of different values of field b 
   grows.
   
   Any suggestions?
   
   Primoz