Venu, For starters,
1) You have used the e.cid twice in ORDER BY clause. 2) If you want last twenty records in the table matching the criteria of timestamp, why do you need the offset? 3) Do you have indexes on sig_id, signature and timestamp fields? If you do not get a good response after that, please post the EXPLAIN ANALYZE for the query. Thanks, Shrirang Chitnis Sr. Manager, Applications Development HOV Services Office: (866) 808-0935 Ext: 39210 shrirang.chit...@hovservices.com www.hovservices.com The information contained in this message, including any attachments, is attorney privileged and/or confidential information intended only for the use of the individual or entity named as addressee. The review, dissemination, distribution or copying of this communication by or to anyone other than the intended addressee is strictly prohibited. If you have received this communication in error, please immediately notify the sender by replying to the message and destroy all copies of the original message. From: pgsql-performance-ow...@postgresql.org [mailto:pgsql-performance-ow...@postgresql.org] On Behalf Of venu madhav Sent: Tuesday, May 11, 2010 2:18 PM To: pgsql-performance@postgresql.org Subject: [PERFORM] Performance issues when the number of records are around 10 Million Hi all, In my database application, I've a table whose records can reach 10M and insertions can happen at a faster rate like 100 insertions per second in the peak times. I configured postgres to do auto vacuum on hourly basis. I have frontend GUI application in CGI which displays the data from the database. When I try to get the last twenty records from the database, it takes around 10-15 mins to complete the operation.This is the query which is used: select e.cid, timestamp, s.sig_class, s.sig_priority, s.sig_name, e.sniff_ip, e.sniff_channel, s.sig_config, e.wifi_addr_1, e.wifi_addr_2, e.view_status, bssid FROM event e, signature s WHERE s.sig_id = e.signature AND e.timestamp >= '1270449180' AND e.timestamp < '1273473180' ORDER BY e.cid DESC, e.cid DESC limit 21 offset 10539780; Can any one suggest me a better solution to improve the performance. Please let me know if you've any further queries. Thank you, Venu -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
