Question on Alerts
Hi,
We are asked to have key monitoring or alerting added to our postgres
database. And I am thinking of metrics like blocked transactions, Max used
transaction Ids, Max Active session threshold, Deadlock, Long running
query, replica lag, buffer cache hit ratio, read/write IOPS or latency
etc. I have below questions
1)Below are some which i tried writing, can you please let me know if these
are accurate?
2)How should we be writing the alerting query for deadlock, max used
transaction ids, read/write IOPS and latency?
3)Are there any docs available which have these sample sql queries on the
pg_* table for these critical alerts which we can easily configure through
any tool?
4)Any other alerts which we should be really having?
*****Blocking sessions
select distinct blocking_id from
(
SELECT
activity.pid,
activity.usename,
activity.query,
blocking.pid AS blocking_id,
blocking.query AS blocking_query
FROM pg_stat_activity AS activity
JOIN pg_stat_activity AS blocking
ON blocking.pid = ANY(pg_blocking_pids(activity.pid))
) a;
**** long running beyond ~1 hours*****
SELECT
query,
datname,
pid,
now() - state_change AS idle_for
FROM pg_stat_activity
WHERE state IN ('active', 'idle in transaction')
AND pid <> pg_backend_pid()
AND xact_start < now() - interval '1 hour'
ORDER BY age(backend_xmin) DESC NULLS LAST;
**** No of active sessions ******
SELECT count(*) AS active_connections
FROM pg_stat_activity
WHERE state = 'active';
***replica lag****
SELECT client_addr, state, sent_location, write_location, flush_location,
replay_location,
pg_wal_lsn_diff(sent_location, replay_location) AS replica_lag
FROM pg_stat_replication;
***buffer cache hit ratio****
SELECT
(1 - (blks_read::float / (blks_hit + blks_read))) * 100 AS
buffer_cache_hit_ratio
FROM pg_stat_database;
Regards
Yudhi
On 2/16/25 05:29, sud wrote:
Hi,
We are asked to have key monitoring or alerting added to our postgres
database. And I am thinking of metrics like blocked transactions, Max
used transaction Ids, Max Active session threshold, Deadlock, Long
running query, replica lag, buffer cache hit ratio, read/write IOPS or
latency etc. I have below questions1)Below are some which i tried writing, can you please let me know if
these are accurate?
2)How should we be writing the alerting query for deadlock, max used
transaction ids, read/write IOPS and latency?
3)Are there any docs available which have these sample sql queries on
the pg_* table for these critical alerts which we can easily configure
through any tool?
4)Any other alerts which we should be really having?
Somewhere to start:
https://wiki.postgresql.org/wiki/Category:Administration#Routine_maintenance_and_monitoring
Regards
Yudhi
--
Adrian Klaver
adrian.klaver@aklaver.com
Hi,
On 16/02/2025 14:29, sud wrote:
Hi,
We are asked to have key monitoring or alerting added to our postgres
database. And I am thinking of metrics like blocked transactions, Max
used transaction Ids, Max Active session threshold, Deadlock, Long
running query, replica lag, buffer cache hit ratio, read/write IOPS or
latency etc. I have below questions1)Below are some which i tried writing, can you please let me know if
these are accurate?
2)How should we be writing the alerting query for deadlock, max used
transaction ids, read/write IOPS and latency?
3)Are there any docs available which have these sample sql queries on
the pg_* table for these critical alerts which we can easily configure
through any tool?
4)Any other alerts which we should be really having?
You should probably look at check_postgres and check_pgactivity. Their
source code contain numerous SQL queries, that could help you write your
own.
Regards.
--
Guillaume Lelarge
Consultant
https://dalibo.com
On Sun, Feb 16, 2025 at 10:05 PM Guillaume Lelarge <
guillaume.lelarge@dalibo.com> wrote:
You should probably look at check_postgres and check_pgactivity. Their
source code contain numerous SQL queries, that could help you write your
own.Regards.
Thank you very much. I am a bit new to postgres here. Can you please guide
me , where exactly I can get the source code for check_postgres and
check_pgactivity?
On Feb 16, 2025, at 12:31, sud <suds1434@gmail.com> wrote:
where exactly I can get the source code for check_postgres and check_pgactivity?
https://github.com/bucardo/check_postgres
https://github.com/OPMDG/check_pgactivity
While the list is happy to help, I should note that I found these by searching for "check_postgres" and "check_pgactivity" using a web search engine, so you might want to do that step first before asking.
On 2/16/25 12:31, sud wrote:
On Sun, Feb 16, 2025 at 10:05 PM Guillaume Lelarge
<guillaume.lelarge@dalibo.com <mailto:guillaume.lelarge@dalibo.com>> wrote:You should probably look at check_postgres and check_pgactivity. Their
source code contain numerous SQL queries, that could help you write
your
own.Regards.
Thank you very much. I am a bit new to postgres here. Can you please
guide me , where exactly I can get the source code for check_postgres
and check_pgactivity?
The way you generally find this information, search on check_postgres
and check_pgactivity.
--
Adrian Klaver
adrian.klaver@aklaver.com