On Tue, Feb 25, 2014 at 11:13 AM, Haribabu Kommi <kommi.harib...@gmail.com>wrote:
> Thanks for the information, I will apply other patches also and start > testing. > When try to run the pgbench test, by default the cache-scan plan is not chosen because of more cost. So I increased the cpu_index_tuple_cost to a maximum value or by turning off index_scan, so that the plan can chose the cache_scan as the least cost. The configuration parameters changed during the test are, shared_buffers - 2GB, cache_scan.num_blocks - 1024 wal_buffers - 16MB, checkpoint_segments - 255 checkpoint_timeout - 15 min, cpu_index_tuple_cost - 100000 or enable_indexscan=off Test procedure: 1. Initialize the database with pgbench with 75 scale factor. 2. Create the triggers on pgbench_accounts 3. Use a select query to load all the data into cache. 4. Run a simple update pgbench test. Plan details of pgbench simple update queries: postgres=# explain update pgbench_accounts set abalance = abalance where aid = 100000; QUERY PLAN ----------------------------------------------------------------------------------------------------------- Update on pgbench_accounts (cost=0.43..100008.44 rows=1 width=103) -> Index Scan using pgbench_accounts_pkey on pgbench_accounts (cost=0.43..100008.44 rows=1 width=103) Index Cond: (aid = 100000) Planning time: 0.045 ms (4 rows) postgres=# explain select abalance from pgbench_accounts where aid = 100000; QUERY PLAN ------------------------------------------------------------------------------------ Custom Scan (cache scan) on pgbench_accounts (cost=0.00..99899.99 rows=1 width=4) Filter: (aid = 100000) Planning time: 0.042 ms (3 rows) I am observing a too much delay in performance results. The performance test script is attached in the mail. please let me know if you find any problem in the test. Regards, Hari Babu Fujitsu Australia
run_reading.sh
Description: Bourne shell script
-- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers