Re: Performance issue in PostgreSQL server...

Dinesh Chandra 12108 <Dinesh.Chandra@xxxxxxxxxx> · Fri, 3 Mar 2017 12:44:07 +0000

Dear Nur,

The below is the output for
psql=> EXPLAIN ANALYZE 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

                                                                                              QUERY PLAN

-------------------------------------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------
Unique  (cost=1679730.32..1679837.46 rows=21428 width=8) (actual time=154753.528..155657.818 rows=1607489 loops=1)
   ->  Sort  (cost=1679730.32..1679783.89 rows=21428 width=8) (actual time=154753.514..155087.734 rows=4053270 loops=1)
         Sort Key: p.feature_id
         Sort Method: quicksort  Memory: 288302kB
         ->  Hash Join  (cost=1501657.09..1678188.87 rows=21428 width=8) (actual time=144146.620..152050.311 rows=4053270 loops=1)
               Hash Cond: (oe.evd_feature_id = p.feature_id)
               Join Filter: ((p.modification_time > '2015-05-10 03:36:56.056+05:30'::timestamp with time zone) OR (oe.modification_time > '2015-05-10 03:36:5
6.056+05:30'::timestamp with time zone))
               ->  Seq Scan on observation_evidence oe  (cost=0.00..121733.18 rows=5447718 width=16) (actual time=0.007..1534.905 rows=5434406 loops=1)
               ->  Hash  (cost=1483472.70..1483472.70 rows=1454751 width=16) (actual time=144144.653..144144.653 rows=1607491 loops=1)
                     Buckets: 262144  Batches: 1  Memory Usage: 75352kB
                     ->  Index Scan using point_domain_class_id_index on point p  (cost=0.00..1483472.70 rows=1454751 width=16) (actual time=27.265..142101.1
59 rows=1607491 loops=1)
                           Index Cond: (domain_class_id = 11)
Total runtime: 155787.379 ms
(13 rows)

Regards,
Dinesh Chandra
|Database administrator (Oracle/PostgreSQL)| Cyient Ltd. Noida.
------------------------------------------------------------------
Mobile: +91-9953975849 | Ext 1078
|dinesh.chandra@xxxxxxxxxx

Plot No. 7, NSEZ, Phase-II ,Noida-Dadri Road, Noida - 201 305,India.

From: Nur Agus [mailto:nuragus.linux@xxxxxxxxx]

Sent: 03 March, 2017 5:54 PM

To: Dinesh Chandra 12108 <Dinesh.Chandra@xxxxxxxxxx>

Cc: pgsql-performance@xxxxxxxxxxxxxx

Subject: Re: [PERFORM] Performance issue in PostgreSQL server...

Hello Dinesh,

You can try the EXPLAIN tool

psql=> EXPLAIN ANALYZE 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

Then paste here the result.

Thanks

On Fri, Mar 3, 2017 at 5:29 PM, Dinesh Chandra 12108 <Dinesh.Chandra@xxxxxxxxxx> wrote:

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)|

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