Re: [SQL] Stats on new tables

> 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
> 
> 
> ************
> 
> 


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