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Re: Perl DBI postgres question (capturing STDERR from VACUUM)

by erix (Vicar)
on Dec 18, 2012 at 11:36 UTC ( #1009345=note: print w/ replies, xml ) Need Help??


in reply to Perl DBI postgres question

Vacuum writes to STDERR so you can redirect & capture that. Here is a program based on an old node by davido (thanks! o/) (which was based on an example in perldoc perlfunc).

It drops/creates a dummy table t, and vacuums it, silently capturing the output (then dumping it in STDOUT):

use strict; use DBI; main(); exit; sub main { my $dbh = DBI->connect("dbi:Pg:", undef,undef, {RaiseError=>1,Prin +tError=>0}); my $table = "t"; $dbh->do("drop table $table") or die "die 1 - $!\n"; $dbh->do("create table t(c text)") or die "die 2 - $!\n"; my $routput = vacuum_analyze($dbh, $table); print "-- verbose output:\n"; print "-"x70, "\n"; print $$routput; print "-"x70, "\n"; } sub vacuum_analyze { my ($dbh, $table) = @_; my $output; open OLDERR, ">&STDERR"; close STDERR; open STDERR, ">", \$output or die "error opening a stderr (heh) +\n"; $dbh->do("vacuum verbose analyze $table"); close STDERR; open STDERR, ">&OLDERR"; \$output; }

Running that gives:

2012.12.18 12:47:31 aardvark@bulldog:~/pg_stuff/pg_sql/pgsql.HEAD [0] $ perl vacuum.pl -- verbose output: ---------------------------------------------------------------------- INFO: vacuuming "public.t" INFO: "t": found 0 removable, 0 nonremovable row versions in 0 out of + 0 pages DETAIL: 0 dead row versions cannot be removed yet. There were 0 unused item pointers. 0 pages are entirely empty. CPU 0.00s/0.00u sec elapsed 0.00 sec. INFO: vacuuming "pg_toast.pg_toast_28335219" INFO: index "pg_toast_28335219_index" now contains 0 row versions in +1 pages DETAIL: 0 index row versions were removed. 0 index pages have been deleted, 0 are currently reusable. CPU 0.00s/0.00u sec elapsed 0.00 sec. INFO: "pg_toast_28335219": found 0 removable, 0 nonremovable row vers +ions in 0 out of 0 pages DETAIL: 0 dead row versions cannot be removed yet. There were 0 unused item pointers. 0 pages are entirely empty. CPU 0.00s/0.00u sec elapsed 0.00 sec. INFO: analyzing "public.t" INFO: "t": scanned 0 of 0 pages, containing 0 live rows and 0 dead ro +ws; 0 rows in sample, 0 estimated total rows ----------------------------------------------------------------------

(PostgreSQL 9.3devel, perl 5.16.2)


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