Re: Autovacuuming - Mailing list pgsql-admin

From Gourish Singbal
Subject Re: Autovacuuming
Date
Msg-id 674d1f8a0604240609m3e2d75a2m89c0654ba94df785@mail.gmail.com
Whole thread Raw
In response to Re: Autovacuuming  (Alvaro Herrera <alvherre@commandprompt.com>)
List pgsql-admin
 
Show autovacuum displays 'on'.
 
db1=# select datname, datvacuumxid, datfrozenxid from pg_database;
       datname       | datvacuumxid | datfrozenxid
---------------------+--------------+--------------
 postgres            |          499 |          499
 db1           |     71677296 |   3292902769
 db2 |     99962197 |   3321187670
 db3       |     72274322 |   3293587302
 template1           |          499 |          499
 template0           |          499 |          499
(6 rows)

db1=# SELECT datname, age(datfrozenxid) FROM pg_database;
       datname       |    age
---------------------+------------
 postgres            |  143239306
 db1          | 1145304332
 db2 | 1117019431
 db3       | 1144619799
 template1           |  143239306
 template0           |  143239306
(6 rows)
 
Since we are currently 465208401 transactions away from the 1610512733.
 
Can i safely sit back and wait for the autovacuum deamon to do its job without any issues ?.
 
 
On 4/24/06, Alvaro Herrera <alvherre@commandprompt.com> wrote:
Gourish Singbal wrote:
> The Age of the database is 1144759836 . We have enabled autovacuuming .
> The details are:-
> autovacuum = on

Are you sure autovacuum is enabled?  Do a "SHOW autovacuum" just to be
sure.

The test for database-wide vacuum is:

database age > big_constant

where:

big_constant = (MaxTransactionId >> 3) * 3 - 100000) = 1610512733
MaxTransactionId = 0xFFFFFFFF
database age = Max(frozen age, vacuum age)
frozen age = next Transaction id - pg_database.datfrozenxid
vacuum age = next Transaction id - pg_database.datvacuumxid


Your database is still 465752897 transactions away from that apparently.

--
Alvaro Herrera                                 http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.



--
Best,
Gourish Singbal

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