I'm having Postgres 9.6.4 in Ubuntu 17. After every few hours (say 6 hours or so), the OS CPU utilization becomes very high (upto 98% or more).
I did the following:
# ps aux | grep postgres
Whenever the process/CPU is high, the above command shows postgres processes like this:
31928 1 ./x3665600000 0.2 99.8
The process name with x3665600000 always consumes near to 100% CPU.
When I checked the pg_stat_activity table, it shows SQL query like this:
select Fun310280 ('./x3665600000 &')
select Fun310280 ('./ps3657178651 &')
What is this function causing Postgres to use very high CPU?
Related
I am running PostgreSQL 9.6 on Centos 7.
The database was migrated from a PostgreSQL 9.4 server that did not have the issue.
With autovacuum on Postgres is using 100% of one core constantly (10% of total CPU). With autovacuum off it does not use any CPU other than when executing queries.
If this expected or normal, or something bad going on? Note it is a very big database, with many schemas/tables.
I tried,
vacuumdb --all -w
and,
ANALYZE VERBOSE;
The "ANALYZE VERBOSE;" made the database run a lot faster, but did not change the CPU usage.
Issue:Analyze running for hours
I kept maintenance worker memory as 1 gb and maintenance workers as 4.DB Size is 40 GB
We upgraded postgres from 11.12 to 13.4.
Post upgrade, i am running analyze as below statement and i am seeing this job runs for hours.
(4 hours still running) .
Any input for this unusual long hours.
Note:
Command i used-> **VACUUM (VERBOSE, ANALYZE,parallel 4)**
Tracking via below statement:
select * from pg_stat_progress_analyze,From this table,I can see per second 250 blocks are scanned
I have a citus cluster of 1 coordinator node (32 vcores , 64 GB RAM) and 6 worker nodes (4 cores , 32 GB RAM each).
After performing ingestion of data using the following command where chunks_0 directory contains 300 files having 1M record each:
find chunks_0/ -type f | time xargs -n1 -P24 sh -c "psql -d citus_testing -c \"\\copy table_1 from '/home/postgres/\$0' with csv HEADER;\""
I notice that after the ingestion is done, there is still a write activity occurring on the worker nodes at smaller rate (was around 800MB/sec overall during ingestion, and around 80-100MB/sec after ingestion) for a certain time.
I'm wondering what is citus doing during this time?
If you do not run any queries in said time period, I do not think Citus is responsible for any writes. It's possible that PostgreSQL ran autovacuum. You can check the PostgreSQL logs in the worker nodes and see for yourself.
I'm running a query that duplicates a very large table (92 million rows) on PostgreSQL. After a 3 iterations I got this error message:
The query was:
CREATE TABLE table_name
AS SELECT * FROM big_table
The issue isn't due to lack of space in the database cluster: at 0.3% of max possible storage at the time of running the query, table size is about 0.01% of max storage including all replicas. I also checked temporary files and it's not that.
You are definitely running out of file system resources.
Make sure you got the size right:
SELECT pg_table_size('big_table');
Don't forget that the files backing the new table are deleted after the error, so it is no surprise that you have lots of free space after the statement has failed.
One possibility is that you are not running out of disk space, but of free i-nodes. How to examine the free resources differs from file system to file system; for ext4 on Linux it would be
sudo dumpe2fs -h /dev/... | grep Free
This question already has answers here:
user postgres launches process that takes all CPUs 100% usage
(2 answers)
Closed 2 years ago.
I installed timescaledb extension (v.5.0) for PostgreSQL (v9.6) on 16.04 Linux box and observes that Postgres process occupies 100% CPU:
here is result of top command:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
19885 postgres 20 0 192684 3916 1420 S 98.3 0.1 5689:04 x3606027128
I run query SELECT pid, datname, usename, query FROM pg_stat_activity and find two weird queries
pid datname username query
19882 postgres postgres select Fun013301 ('./x3606027128 &')
19901 postgres postgres select Fun013301 ('./ps3597605779 &')
function Fun013301 is not existed in postgres database. I cannot figure out what ./x3606027128 command is!?
I had a similar issue. It was due to - some transactions was getting stuck and running for long time. Thus, CPU utilization was at 100% all the time. Following command helped to find out the connections running for the longest time:
SELECT max(now() - xact_start) FROM pg_stat_activity
WHERE state IN ('idle in transaction', 'active');
This command shows the time since when a connection is running. This time should not be greater than an hour. So killing the connection which was running from long time or stuck at any point, worked for me. I followed this post for monitoring and solving my issue. Post includes lots of useful commands to monitor this situation.