Thread: pg_xlog question
Questions on pg_xlog: 1. what parameter tells postgress to always keep 7 files in the pg_xlog directory? (see below) --this is test database we are learning on. (and it seems everytime that I look at this directory there are always 7 entries there) 2. What happens when the files increment and can no longer increment to a higher number (the file name)? 3. Is there a way to "reset" the number so that this won't happen? total 114800 -rw------- 1 pgsql pgsql 16777216 May 6 19:07 00000009000000CC -rw------- 1 pgsql pgsql 16777216 May 6 19:08 00000009000000CD -rw------- 1 pgsql pgsql 16777216 May 6 19:09 00000009000000CE -rw------- 1 pgsql pgsql 16777216 May 7 08:23 00000009000000CF -rw------- 1 pgsql pgsql 16777216 May 7 08:25 00000009000000D0 -rw------- 1 pgsql pgsql 16777216 May 22 10:32 00000009000000D1 -rw------- 1 pgsql pgsql 16777216 Jul 9 16:23 00000009000000CB $ pwd /usr/local/pgsql/data/pg_xlog $ Thank you Pam Wampler
Pam Wampler <Pam_Wampler@taylorwhite.com> writes: > 1. what parameter tells postgress to always keep 7 files in the pg_xlog > directory? (see below) --this is test database we > are learning on. (and it seems everytime that I look at this directory there > are always 7 entries there) It's basically 2 * checkpoint_segments + 1. See http://www.ca.postgresql.org/users-lounge/docs/7.2/postgres/wal-configuration.html > 2. What happens when the files increment and can no longer increment to a > higher number (the file name)? Trouble, which is why we use a 64-bit counter. > 3. Is there a way to "reset" the number so that this won't happen? initdb. However, you're not gonna have to worry about it in your lifetime. Do the math... regards, tom lane