Continous increase in insertion rate with time!!!

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От Rajan Bhide
Тема Continous increase in insertion rate with time!!!
Дата
Msg-id FF851C7EEB75954F9BCFB5CA117AB1EC013FE2D4@delta.nulinkinc.com
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Ответы Re: Continous increase in insertion rate with time!!!
Список pgsql-novice
Hi Group,

I am finding an increase in insertion rate with time with steady
insertion and updation rate of 70 records per sec with my app using
Postgres 7.4.5 on Solaris 5.8.
I am using Postgres7.4.5 on solaris5.8 (1-Gig Ram) machine.
During the initial stages say Ist 1hr or so, the insertion rate is about
5 sec per insert but it slowly starts building up with time and after 24
hour goes to 12-15 sec and after 48hr goes to 25 sec. Update is fast and
is in less than a sec.
I have attached the postgres conf file and the statistics collected
during the run.
Is this a known feature (or limitation). How can I avoid this by
minimising the disk read?
Shld I consider updating postgresql.conf with more appropriate values.
(i.e disabling fysnc and check pointing based on chkpoint timeout as I
perform continous insert -> update and then batch delete)


****************************************
postgresql.conf
****************************************
max_connections = 100
shared_buffers = 32000 #(Org 1000)
sort_mem = 8192 #(Org 1024)

fsync = true
wal_sync_method = fsync
wal_buffers = 8
checkpoint_segments = 10 #(Org 3)
effective_cache_size = 1000
****************************************



cdr_backup=# select * from  pg_stat_user_tables;
  relid  |     schemaname     |         relname         | seq_scan |
seq_tup_read | idx_scan | idx_tup_fetch | n_tup_ins | n_tup_upd |
n_tup_del
---------+--------------------+-------------------------+----------+----
----------+----------+---------------+-----------+-----------+----------
-
 9471204 | public             | cdr                     |    41069 |
39957057 |        1 |             0 |  19056991 |         0 |  19054378
 9471214 | public             | cdr_archive             |     2327 |
23331784 |   492714 |      19233822 |  19054379 |         0 |  19031842

cdr_backup=# select * from pg_stat_user_indexes;
  relid  | indexrelid | schemaname |     relname     |
indexrelname          | idx_scan | idx_tup_read | idx_tup_fetch
---------+------------+------------+-----------------+------------------
--------------+----------+--------------+---------------
 9471214 |    9471222 | public     | cdr_archive     |
cdr_archive_accesstime_key     |   492785 |     19233822 |      19233822
 9471204 |    9471212 | public     | cdr             | cdr_transid_key
|        1 |            0 |             0


cdr_backup=# select * from pg_statio_user_indexes;
  relid  | indexrelid | schemaname |     relname     |
indexrelname          | idx_blks_read | idx_blks_hit
---------+------------+------------+-----------------+------------------
--------------+---------------+--------------
 9471214 |    9471222 | public     | cdr_archive     |
cdr_archive_accesstime_key     |          1472 |     73638177
 9471204 |    9471212 | public     | cdr             | cdr_transid_key
|           934 |     58408992


cdr_backup=# select * from pg_statio_user_indexes;
  relid  | indexrelid | schemaname |     relname     |
indexrelname          | idx_blks_read | idx_blks_hit
---------+------------+------------+-----------------+------------------
--------------+---------------+--------------
 9471214 |    9471222 | public     | cdr_archive     |
cdr_archive_accesstime_key     |          1472 |     73638267
 9471204 |    9471212 | public     | cdr             | cdr_transid_key
|           934 |     58408992
(4 rows)

cdr_backup=# select * from pg_statio_user_tables;
  relid  |     schemaname     |         relname         | heap_blks_read
| heap_blks_hit | idx_blks_read | idx_blks_hit | toast_blks_read |
toast_blks_hit | tidx_blks_read | tidx_blks_hit
---------+--------------------+-------------------------+---------------
-+---------------+---------------+--------------+-----------------+-----
-----------+----------------+---------------
 9471204 | public             | cdr                     |          19912
|     137570556 |           934 |     58408992 |              76 |
1318 |              2 |          1226
 9471214 | public             | cdr_archive             |         222246
|     112726711 |          1472 |     73638408 |             122 |
2316 |              2 |          4511


Thanks,
Rajan

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