Hi, I'm trying to measure the performance of the following: Multiple txns inserting tuples into a table concurrently vs single txn doing the whole insertion.
*new table created as:* create table tab2 ( id serial, attr1 integer not null, attr2 integer not null, primary key(id) ); *EXP 1: inserts with multiple txn:* insert into tab2 (attr1, attr2) (select attr1, attr2 from tab1 where attr2 = 10); insert into tab2 (attr1, attr2) (select attr1, attr2 from tab1 where attr2 = 20); note: attr2 has only two values 10 and 20 *EXP 2: inserts with a single txn:* insert into tab2 (attr1, attr2) (select attr1, attr2 from tab1); I also performed another experiment as follows: *EXP 3:* select attr1, attr2 into tab2 from tab1; The observation here is EXP 3 is much faster than EXP 2 probably due to bulk inserts used by Postgres. However I could not find a way to insert id values in tab2 using EXP 3. Also select .. into .. from .. throws an error if we create a table first and then populate the tuples using the command. I have the following questions: 1. Is it possible to have an id column in tab2 and perform a bulk insert using select .. into .. from .. or using some other means? 2. If a table is already created, is it possible to do bulk inserts via multiple txns inserting into the same table (EXP 3)? Best, -SB
