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All,

I see that an auto vacuum process that has started on April 08 is still continuing till date on a production server
thatI manage. 

Some statistics related to the process are as listed below. The queries are below statistics.

1) ps -aux | grep ^postgres

postgres 24188  0.0  2.4 14038764 809904 ?   Ss   Apr08   1:05 postgres: autovacuum worker process   sbcoasis

2) select * from pg_lock

locktype | database | relation | page | tuple | virtualxid | transactionid | classid | objid | objsubid |
virtualtransaction|  pid  |           mode           | granted 

----------+----------+----------+------+-------+------------+---------------+---------+-------+----------+--------------------+-------+--------------------------+---------
relation |    16384 |    18349 |      |       |            |               |         |       |          | 5/6082308
    | 24188 | ShareUpdateExclusiveLock | t 

3) pg_stat_user_tables values

relid | n_live_tup | n_tup_hot_upd | n_dead_tup | n_tup_ins | n_tup_del
-------+------------+---------------+------------+-----------+-----------
 18349 | 1245123345 |             0 |          3 |  76479925 |         5

relid |        last_autovacuum        |       last_autoanalyze
-------+-------------------------------+-------------------------------
18349 | 2009-03-29 20:36:59.18137-07  | 2009-04-07 21:48:09.646087-07

4) Postgres Configuration Parameters:

# - Memory -

shared_buffers = 12GB           # min 128kB or max_connections*16kB
                                        # (change requires restart)
#temp_buffers = 8MB                     # min 800kB
#max_prepared_transactions = 5          # can be 0 or more
                                        # (change requires restart)
# Note:  Increasing max_prepared_transactions costs ~600 bytes of shared memory
# per transaction slot, plus lock space (see max_locks_per_transaction).
work_mem = 2GB                          # min 64kB
maintenance_work_mem = 1GB              # min 1MB
#max_stack_depth = 2MB                  # min 100kB

# - Free Space Map -

max_fsm_pages = 1500000                 # min max_fsm_relations*16, 6 bytes each
                                        # (change requires restart)
max_fsm_relations = 500         # min 100, ~70 bytes each
                                        # (change requires restart)

# - Kernel Resource Usage -

#max_files_per_process = 1000           # min 25
                                        # (change requires restart)
#shared_preload_libraries = ''          # (change requires restart)

# - Cost-Based Vacuum Delay -

vacuum_cost_delay = 5                   # 0-1000 milliseconds


5) The server has quad processors with 32 GB RAM.


--------------------------------------------------------------------------------------------------------------------------------------------------------

Queries

From past experience, running a manual vacuum and analyze on the table after a couple of days took around 12 - 16
hours,so the time taken for the current process seems over the top. It also stops me from running reindex routine
(whichwas to happen last week - runs once a month), as the indexing routine waited for the vacuum to be completed and
hadto be cancelled. 

A) Is there a way to know whether the process is still running or is stalled?
B) Can the process be killed safely without causing issues in the autovacuum daemon?
C) Is there a way to know the percentage of autovacuum completed on a table?
D) Can I speed up the autovacuum process in some way? Will increasing the maintenance_work_mem affect other processes?


Please let me know if more information is required to resolve the issue.


Thanks in advance.


Shrirang.


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