what happens when concurrent index create

On Tue, Apr 3, 2012 at 9:50 PM, leo xu <leoxu8703@gmail.com> wrote:

i read documents,i find it that concurrent index create don't lock
write.but
need scan table twice.it explain is following as:
It scans the table once to initially build the index, then makes a second
pass to look for things added after the first pass.

please explain 1. what happens when concurrent index create .tks.
2.how to trace a backend what do somethings internal.for
example oracle 10046 trace.

It seems you are looking for a similar behavior of sql_trace in oracle. You
can try pgstatstatements contrib module.

http://www.postgresql.org/docs/9.1/static/pgstatstatements.html

---
Regards,
Raghavendra
EnterpriseDB Corporation
Blog: http://raghavt.blogspot.com/

leo xu wrote:

i read documents,i find it that concurrent index create don't lock

write.but

need scan table twice.it explain is following as:
It scans the table once to initially build the index, then makes a

second

pass to look for things added after the first pass.

please explain 1. what happens when concurrent index create .tks.

You quoted the explanation above...
If you need to know more, read the source: it is the function
DefineIndex
in src/backend/commands/indexcmds.c

2.how to trace a backend what do somethings

internal.for

example oracle 10046 trace.

SET log_min_messages=DEBUG5;

Then do what you want logged. Afterwards read the log file.

You need to be superuser for this command. If you want to switch
to a regular user after issuing the command, say

SET SESSION AUTHORIZATION some_user;

Yours,
Laurenz Albe