> I think I've found something of interest.
> When I create a new table, the plan for it believes that the table
> contains 2 rows, not 0. Also, since the engine knows when we run an
> insert, and also knows how many rows a delete nukes, wouldn't it be better
> to update the stats after every select and delete?
We believe the overhead of that would be high vs. the benefits.
>
> -Michael
>
>
> equipment=> CREATE TABLE xuserid(
> equipment-> oldid varchar(12),
> equipment-> newid int4,
> equipment-> PRIMARY KEY (oldid,newid)
> equipment-> );
> NOTICE: CREATE TABLE/PRIMARY KEY will create implicit index
> 'xuserid_pkey' for table 'xuserid'
> CREATE
> equipment=> \d xuserid_pkey
> Table = xuserid_pkey
> +----------------------------------+----------------------------------+-------+
> | Field | Type |
> Length|
> +----------------------------------+----------------------------------+-------+
> | oldid | varchar() |
> 12 |
> | newid | int4 |
> 4 |
> +----------------------------------+----------------------------------+-------+
> equipment=> explain select * from xuserid where newid=859;
> NOTICE: QUERY PLAN:
>
> Seq Scan on xuserid (cost=43.00 rows=2 width=16)
>
> EXPLAIN
> equipment=> vacuum analyze;
> VACUUM
> equipment=> explain select * from xuserid where newid=859;
> NOTICE: QUERY PLAN:
>
> Seq Scan on xuserid (cost=0.00 rows=0 width=16)
>
> EXPLAIN
>
>
> ************
>
>
-- Bruce Momjian | http://www.op.net/~candle maillist@candle.pha.pa.us | (610)
853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill,
Pennsylvania19026
