Dear Experts, I need your suggestions to resolve the performance issue reported on our PostgreSQL9.1 production database having 1.5 TB Size. I have observed that, some select queries with order by clause are taking lot of time in execution and forcing applications to give slow response.
The configuration of database server is : Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit CPU's : 8 Core(s) per socket: 4 Socket(s): 2 Model name: Intel(R) Xeon(R) CPU E5-2609 0 @ 2.40GHz RAM : 32 GB SWAP :8 Gb Kernel parameter: kernel.shmmax = 32212254720 kernel.shmall = 1073741824 Values of PostgreSQL.conf parameters are : shared_buffers = 10GB temp_buffers = 32MB work_mem = 512MB maintenance_work_mem = 2048MB max_files_per_process = 2000 checkpoint_segments = 200 max_wal_senders = 5 wal_buffers = -1 # min 32kB, -1 sets based on shared_buffers Queries taking lot of time are: ================================== 2017-03-02 00:46:50 IST LOG: duration: 2492951.927 ms execute <unnamed>: SELECT DISTINCT feature_id FROM evidence.point p INNER JOIN evidence.observation_evidence oe ON p.feature_id = oe.evd_feature_id WHERE p.domain_class_id IN (11) AND (p.modification_time > '2015-05-10 00:06:56.056 IST' OR oe.modification_time > '2015-05-10 00:06:56.056 IST') ORDER BY feature_id 2017-03-02 01:05:16 IST LOG: duration: 516250.512 ms execute <unnamed>: SELECT DISTINCT feature_id FROM evidence.point p INNER JOIN evidence.observation_evidence oe ON p.feature_id = oe.evd_feature_id WHERE p.domain_class_id IN (3) AND (p.modification_time > '2015-05-10 01:22:59.059 IST' OR oe.modification_time > '2015-05-10 01:22:59.059 IST') ORDER BY feature_id Top command output: top - 15:13:15 up 66 days, 3:45, 8 users, load average: 1.84, 1.59, 1.57 Tasks: 830 total, 1 running, 828 sleeping, 0 stopped, 1 zombie Cpu(s): 3.4%us, 0.7%sy, 0.0%ni, 81.7%id, 14.2%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 32830016k total, 32142596k used, 687420k free, 77460k buffers Swap: 8190972k total, 204196k used, 7986776k free, 27981268k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 30639 postgres 20 0 10.5g 4.7g 4.7g S 13.5 14.9 10:20.95 postgres 18185 postgres 20 0 10.5g 603m 596m S 4.9 1.9 2:51.16 postgres 16543 postgres 20 0 10.5g 2.8g 2.8g S 4.3 8.8 1:34.04 postgres 14710 postgres 20 0 10.5g 2.9g 2.9g S 3.9 9.2 1:20.84 postgres 1214 root 20 0 15668 1848 896 S 1.0 0.0 130:46.43 top 13462 postgres 20 0 10.5g 1.4g 1.3g S 1.0 4.3 0:25.56 postgres 20081 root 20 0 15668 1880 936 R 1.0 0.0 0:00.12 top 13478 postgres 20 0 10.5g 2.1g 2.1g S 0.7 6.9 0:56.43 postgres 41107 root 20 0 416m 10m 4892 S 0.7 0.0 305:25.71 pgadmin3 2680 root 20 0 0 0 0 S 0.3 0.0 103:38.54 nfsiod 3558 root 20 0 13688 1100 992 S 0.3 0.0 45:00.36 gam_server 15576 root 20 0 0 0 0 S 0.3 0.0 0:01.16 flush-253:1 18430 postgres 20 0 10.5g 18m 13m S 0.3 0.1 0:00.64 postgres 20083 postgres 20 0 105m 1852 1416 S 0.3 0.0 0:00.01 bash 24188 postgres 20 0 102m 1856 832 S 0.3 0.0 0:23.39 sshd 28250 postgres 20 0 156m 1292 528 S 0.3 0.0 0:46.86 postgres 1 root 20 0 19356 1188 996 S 0.0 0.0 0:05.00 init Regards, Dinesh Chandra |Database administrator (Oracle/PostgreSQL)| ________________________________ DISCLAIMER: This email message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. Check all attachments for viruses before opening them. All views or opinions presented in this e-mail are those of the author and may not reflect the opinion of Cyient or those of our affiliates.
