I have seen that autovacuum takes long time to process . please give me the reason ...... On Mon, Aug 8, 2011 at 2:10 PM, Tomas Vondra <tv@xxxxxxxx> wrote: > On 8 Srpen 2011, 8:02, Vivekkumar Pandey wrote: >> Hi , >> >> I have version of PostgreSQL as given below:--- >> >> version >> ------------------------------------------------------------------------------------- >> PostgreSQL 8.1.2 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) >> 3.3.3 (SuSE Linux) >> >> And it does't have any n_dead_tup columns in pg_stat_all_tables like this: > > That's because this column was added in 8.3. > > BTW you're using a way too old version. It's not just that 8.1 is > unsupported, but the last minor subversion in this branch is 8.1.23. There > were numerous bugfixes since 8.1.2, so you should upgrade at least to this > version (and plan to upgrade to something more fresh). > >> In what situations table creates a new row instead of using deleted >> marked tuples that's why size of table increases abnormally. > > Whenever a row is modified - that means insert, update or delete. That's > how PostgreSQL MVCC works. This wasted space needs to be reclaimed, which > is exactly what (auto)vacuum does. > > PS: With HOT this is not exactly true, but HOT is not available in 8.1 > anyway. Another reason to upgrade to a more recent version. > > Tomas > > > -- > Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general > -- Thanks VIVEK KUMAR PANDEY -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
