From 1f8b5e0a4d24235632ea6714f85a58e9b1bee0bb Mon Sep 17 00:00:00 2001 From: Thomas Menard Date: Fri, 18 Mar 2016 15:45:29 +0100 Subject: [PATCH] Updated README.md Add some comments and sample configs --- .../inputs/postgresql_extensible/README.md | 198 ++++++++++++++++-- 1 file changed, 185 insertions(+), 13 deletions(-) diff --git a/plugins/inputs/postgresql_extensible/README.md b/plugins/inputs/postgresql_extensible/README.md index f44c66596..ae49a9b3e 100644 --- a/plugins/inputs/postgresql_extensible/README.md +++ b/plugins/inputs/postgresql_extensible/README.md @@ -1,17 +1,21 @@ # PostgreSQL plugin -This postgresql plugin provides metrics for your postgres database. It has been designed to parse ithe sql queries in the plugin section of your telegraf.conf. +This postgresql plugin provides metrics for your postgres database. It has been +designed to parse ithe sql queries in the plugin section of your telegraf.conf. -For now only two queries are specified and it's up to you to add more; some per query parameters have been added : +For now only two queries are specified and it's up to you to add more; some per +query parameters have been added : * The SQl query itself * The minimum version supported (here in numeric display visible in pg_settings) -* A boolean to define if the query have to be run against some specific variables (defined in the databaes variable of the plugin section) +* A boolean to define if the query have to be run against some specific +* variables (defined in the databaes variable of the plugin section) * The list of the column that have to be defined has tags ``` +[[inputs.postgresql_extensible]] # specify address via a url matching: - # postgres://[pqgotest[:password]]@localhost[/dbname]?sslmode=[disable|verify-ca|verify-full] + # postgres://[pqgotest[:password]]@localhost[/dbname]?sslmode=... # or a simple string: # host=localhost user=pqotest password=... sslmode=... dbname=app_production # @@ -27,15 +31,19 @@ For now only two queries are specified and it's up to you to add more; some per # databases = ["app_production", "testing"] # # Define the toml config where the sql queries are stored - # New queries can be added, if the withdbname is set to true and there is no databases defined - # in the 'databases field', the sql query is ended by a 'is not null' in order to make the query - # succeed. - # Be careful that the sqlquery must contain the where clause with a part of the filtering, the plugin will - # add a 'IN (dbname list)' clause if the withdbname is set to true + # New queries can be added, if the withdbname is set to true and there is no + # databases defined in the 'databases field', the sql query is ended by a 'is + # not null' in order to make the query succeed. + # Be careful that the sqlquery must contain the where clause with a part of + # the filtering, the plugin will add a 'IN (dbname list)' clause if the + # withdbname is set to true # Example : - # The sqlquery : "SELECT * FROM pg_stat_database where datname" become "SELECT * FROM pg_stat_database where datname IN ('postgres', 'pgbench')" - # because the databases variable was set to ['postgres', 'pgbench' ] and the withdbname was true. - # Be careful that if the withdbname is set to false you d'ont have to define the where clause (aka with the dbname) + # The sqlquery : "SELECT * FROM pg_stat_database where datname" become + # "SELECT * FROM pg_stat_database where datname IN ('postgres', 'pgbench')" + # because the databases variable was set to ['postgres', 'pgbench' ] and the + # withdbname was true. + # Be careful that if the withdbname is set to false you d'ont have to define + # the where clause (aka with the dbname) # the tagvalue field is used to define custom tags (separated by comas) # # Structure : @@ -56,4 +64,168 @@ For now only two queries are specified and it's up to you to add more; some per tagvalue="" ``` -The system can be easily extended using homemade metrics collection tools or using postgreql extensions ([pg_stat_statements](http://www.postgresql.org/docs/current/static/pgstatstatements.html), [pg_proctab](https://github.com/markwkm/pg_proctab), [powa](http://dalibo.github.io/powa/)...) +The system can be easily extended using homemade metrics collection tools or +# using postgreql extensions ( +[pg_stat_statements](http://www.postgresql.org/docs/current/static/pgstatstatements.html), [pg_proctab](https://github.com/markwkm/pg_proctab), +[powa](http://dalibo.github.io/powa/)...) + +# Sample Queries : +- telegraf.conf postgresql_extensible queries (assuming that you have configured + correctly your connection) +``` +[[inputs.postgresql_extensible.query]] + sqlquery="SELECT * FROM pg_stat_database" + version=901 + withdbname=false + tagvalue="" +[[inputs.postgresql_extensible.query]] + sqlquery="SELECT * FROM pg_stat_bgwriter" + version=901 + withdbname=false + tagvalue="" +[[inputs.postgresql_extensible.query]] + sqlquery="select * from sessions" + version=901 + withdbname=false + tagvalue="db,username,state" +[[inputs.postgresql_extensible.query]] + sqlquery="select setting as max_connections from pg_settings where \ + name='max_connections'" + version=801 + withdbname=false + tagvalue="" +[[inputs.postgresql_extensible.query]] + sqlquery="select * from pg_stat_kcache" + version=901 + withdbname=false + tagvalue="" +[[inputs.postgresql_extensible.query]] + sqlquery="select setting as shared_buffers from pg_settings where \ + name='shared_buffers'" + version=801 + withdbname=false + tagvalue="" +[[inputs.postgresql_extensible.query]] + sqlquery="SELECT db, count( distinct blocking_pid ) AS num_blocking_sessions,\ + count( distinct blocked_pid) AS num_blocked_sessions FROM \ + public.blocking_procs group by db" + version=901 + withdbname=false + tagvalue="db" +``` + +- And on the posgtgres side : + +* postgresql.conf +```` +shared_preload_libraries = 'pg_stat_statements,pg_stat_kcache' +``` +* In the database (can be a specific monitoring db) +``` +create extension pg_stat_statements; +create extension pg_stat_kcache; +create extension pg_proctab; +``` +(assuming that the extension is installed on the OS Layer) + +* pg_stat_kcache is available on the postgresql.org yum repo +* pg_proctab is available at : https://github.com/markwkm/pg_proctab + +* Views +** Blocking sessions +``` +CREATE OR REPLACE VIEW public.blocking_procs AS + SELECT a.datname AS db, + kl.pid AS blocking_pid, + ka.usename AS blocking_user, + ka.query AS blocking_query, + bl.pid AS blocked_pid, + a.usename AS blocked_user, + a.query AS blocked_query, + to_char(age(now(), a.query_start), 'HH24h:MIm:SSs'::text) AS age + FROM pg_locks bl + JOIN pg_stat_activity a ON bl.pid = a.pid + JOIN pg_locks kl ON bl.locktype = kl.locktype AND NOT bl.database IS + DISTINCT FROM kl.database AND NOT bl.relation IS DISTINCT FROM kl.relation + AND NOT bl.page IS DISTINCT FROM kl.page AND NOT bl.tuple IS DISTINCT FROM + kl.tuple AND NOT bl.virtualxid IS DISTINCT FROM kl.virtualxid AND NOT + bl.transactionid IS DISTINCT FROM kl.transactionid AND NOT bl.classid IS + DISTINCT FROM kl.classid AND NOT bl.objid IS DISTINCT FROM kl.objid AND + NOT bl.objsubid IS DISTINCT FROM kl.objsubid AND bl.pid <> kl.pid + JOIN pg_stat_activity ka ON kl.pid = ka.pid + WHERE kl.granted AND NOT bl.granted + ORDER BY a.query_start; +``` +** Sessions Statistics +``` +CREATE OR REPLACE VIEW public.sessions AS + WITH proctab AS ( + SELECT pg_proctab.pid, + CASE + WHEN pg_proctab.state::text = 'R'::bpchar::text + THEN 'running'::text + WHEN pg_proctab.state::text = 'D'::bpchar::text + THEN 'sleep-io'::text + WHEN pg_proctab.state::text = 'S'::bpchar::text + THEN 'sleep-waiting'::text + WHEN pg_proctab.state::text = 'Z'::bpchar::text + THEN 'zombie'::text + WHEN pg_proctab.state::text = 'T'::bpchar::text + THEN 'stopped'::text + ELSE NULL::text + END AS proc_state, + pg_proctab.ppid, + pg_proctab.utime, + pg_proctab.stime, + pg_proctab.vsize, + pg_proctab.rss, + pg_proctab.processor, + pg_proctab.rchar, + pg_proctab.wchar, + pg_proctab.syscr, + pg_proctab.syscw, + pg_proctab.reads, + pg_proctab.writes, + pg_proctab.cwrites + FROM pg_proctab() pg_proctab(pid, comm, fullcomm, state, ppid, pgrp, + session, tty_nr, tpgid, flags, minflt, cminflt, majflt, cmajflt, + utime, stime, cutime, cstime, priority, nice, num_threads, + itrealvalue, starttime, vsize, rss, exit_signal, processor, + rt_priority, policy, delayacct_blkio_ticks, uid, username, rchar, + wchar, syscr, syscw, reads, writes, cwrites) + ), stat_activity AS ( + SELECT pg_stat_activity.datname, + pg_stat_activity.pid, + pg_stat_activity.usename, + CASE + WHEN pg_stat_activity.query IS NULL THEN 'no query'::text + WHEN pg_stat_activity.query IS NOT NULL AND + pg_stat_activity.state = 'idle'::text THEN 'no query'::text + ELSE regexp_replace(pg_stat_activity.query, '[\n\r]+'::text, + ' '::text, 'g'::text) + END AS query + FROM pg_stat_activity + ) + SELECT stat.datname::name AS db, + stat.usename::name AS username, + stat.pid, + proc.proc_state::text AS state, +('"'::text || stat.query) || '"'::text AS query, + (proc.utime/1000)::bigint AS session_usertime, + (proc.stime/1000)::bigint AS session_systemtime, + proc.vsize AS session_virtual_memory_size, + proc.rss AS session_resident_memory_size, + proc.processor AS session_processor_number, + proc.rchar AS session_bytes_read, + proc.rchar-proc.reads AS session_logical_bytes_read, + proc.wchar AS session_bytes_written, + proc.wchar-proc.writes AS session_logical_bytes_writes, + proc.syscr AS session_read_io, + proc.syscw AS session_write_io, + proc.reads AS session_physical_reads, + proc.writes AS session_physical_writes, + proc.cwrites AS session_cancel_writes + FROM proctab proc, + stat_activity stat + WHERE proc.pid = stat.pid; +```