On Wed, 27 Nov 2002, Tom Lane wrote: > Achilleus Mantzios <[EMAIL PROTECTED]> writes: > > Linux q1 > > ======== > > dynacom=# EXPLAIN ANALYZE SELECT count(*) from noon; > > NOTICE: QUERY PLAN: > > > Aggregate (cost=20508.19..20508.19 rows=1 width=0) (actual > > time=338.17..338.17 > > rows=1 loops=1) > > -> Seq Scan on noon (cost=0.00..20237.95 rows=108095 width=0) (actual > > time=0.01..225.73 rows=108095 loops=1) > > Total runtime: 338.25 msec > > > Linux q2 > > ======== > > dynacom=# EXPLAIN ANALYZE SELECT * from noon; > > NOTICE: QUERY PLAN: > > > Seq Scan on noon (cost=0.00..20237.95 rows=108095 width=1960) (actual > > time=1.22..67909.31 rows=108095 loops=1) > > Total runtime: 68005.96 msec > > You didn't say what was *in* the table, exactly ... but I'm betting > there are a lot of toasted columns, and that the extra runtime > represents the time to fetch (and perhaps decompress) the TOAST entries.
Are there any reason to "fetch (and perhaps decompress) the TOAST entries" just to count(*) without any WHERE clause ? > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster > Regards, Oleg _____________________________________________________________ Oleg Bartunov, sci.researcher, hostmaster of AstroNet, Sternberg Astronomical Institute, Moscow University (Russia) Internet: [EMAIL PROTECTED], http://www.sai.msu.su/~megera/ phone: +007(095)939-16-83, +007(095)939-23-83 ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster