[GENERAL] High load average every 105 minutes
I have Postgresql 9.3 installed on AWS instance ubuntu 14.04 The load average of the instance increase every 105 minutes even without any database. I’ve checked the scheduled jobs but couldn’t find anything suspicious. When the load average was at peak, I couldn’t see any process consuming resources. This happens on all my servers that has postgresql installed, even after I purge postgresql. Has anyone seen this before? Here’s my config: postgresql.conf data_directory = '/var/lib/postgresql/9.3/main' hba_file = '/etc/postgresql/9.3/main/pg_hba.conf' ident_file = '/etc/postgresql/9.3/main/pg_ident.conf' external_pid_file = '/var/run/postgresql/9.3-main.pid' listen_addresses = '*' port = 5432 max_connections = 100 unix_socket_directories = '/var/run/postgresql' ssl = true ssl_cert_file = '/etc/ssl/certs/ssl-cert-snakeoil.pem' ssl_key_file = '/etc/ssl/private/ssl-cert-snakeoil.key' shared_buffers = 128MB shared_preload_libraries = 'pg_stat_statements' wal_level = hot_standby checkpoint_segments = 8 max_wal_senders = 3 wal_keep_segments = 8 log_min_duration_statement = 300 log_line_prefix = '%m ' log_timezone = 'UTC' datestyle = 'iso, mdy' timezone = 'UTC' lc_messages = 'en_US.UTF-8' lc_monetary = 'en_US.UTF-8' lc_numeric = 'en_US.UTF-8' lc_time = 'en_US.UTF-8' default_text_search_config = 'pg_catalog.english' Nhan Nguyen System Engineer MB: (+84) 934 008 031 Skype: live:ducnhan813
Re: [GENERAL] High load average every 105 minutes
Thanks for the reply. I found no strange processes or queries while load average was at peak. IO also didn't change. Some more slow queries were logged, but not many. I think sharing the VM with other customers doesn’t have much to do with this. I checked my other servers too, and only those that have postgresql have the load average issue. Generally it doesn’t impact my system much, but when there are slow queries, this issue just makes everything worse. Nhan Nguyen System Engineer MB: (+84) 934 008 031 Skype: live:ducnhan813 > On Nov 4, 2016, at 4:03 PM, John R Pierce wrote: > > On 11/4/2016 1:45 AM, Nhan Nguyen wrote: >> >> The load average of the instance increase every 105 minutes even without any >> database. I’ve checked the scheduled jobs but couldn’t find anything >> suspicious. When the load average was at peak, I couldn’t see any process >> consuming resources. This happens on all my servers that has postgresql >> installed, even after I purge postgresql. Has anyone seen this before > > load average doesn't mean much other than the number of processes waiting for > a resource. does the IO latency spike at this time, too? > > with AWS, your system is sharing the vendors virtual machine environment with > other customers, and performance is pretty much out of your control. > > -- > john r pierce, recycling bits in santa cruz > > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] High load average every 105 minutes
I forgot to mention, my DB is running on a c4.xlarge instance. Nhan Nguyen System Engineer MB: (+84) 934 008 031 Skype: live:ducnhan813 > On Nov 7, 2016, at 5:03 PM, Chris Mair wrote: > > >>> with AWS, your system is sharing the vendors virtual machine environment >>> with other customers, and performance is pretty much out of your control. > >> I found no strange processes or queries while load average was at peak. IO >> also didn't change. Some more slow queries were logged, but not many. >> I think sharing the VM with other customers doesn’t have much to do with >> this. I checked my other servers too, and only those that have postgresql >> have the load average issue. Generally it doesn’t impact my system much, but >> when there are slow queries, this issue just makes everything worse. > > Hi, > > generally speaking AWS is pretty good at isolating users (and you can request > single tenancy machines or > dedicated machines as well if you're concerned about this). > > However, if you're running t1 or t2 instances, you get the concept of CPU > credits. When those run out, your > system is slowed down until the credits recover. I could imagine that this > way some cyclic load patterns > emerge, if there is constant load on the machines. > > Nhan, what instance types are you running? > > Bye, > Chris. > > >
