>To spare memory, you would want to use something like: >insert into test01 select generate_series, >repeat(chr(int4(random()*26)+65),1024) from >generate_series(1,2457600);
Thanks a lot! What I am worrying about is that: If data grows rapidly, maybe our customer will use too much memory , Is ulimit command a good idea for PG? Best Regards 2013/9/1 Jeff Janes <[email protected]> > On Fri, Aug 30, 2013 at 2:10 AM, 高健 <[email protected]> wrote: > > > > > > postgres=# insert into test01 values(generate_series(1,2457600),repeat( > > chr(int4(random()*26)+65),1024)); > > The construct "values (srf1,srf2)" will generate its entire result set > in memory up front, it will not "stream" its results to the insert > statement on the fly. > > To spare memory, you would want to use something like: > > insert into test01 select generate_series, > repeat(chr(int4(random()*26)+65),1024) from > generate_series(1,2457600); > > Cheers, > > Jeff >
