Postgres CPU 과다 사용 ( high CPU Usage )

PostgreSQL CPU 과다 사용 ( high CPU Usage )

Postgres 프로세스중에서 CPU가 높은 PID를 찾고, 해당 PID를 통해서 Postgres ID를 찾아,

실행중인 query문장을 찾는다.

>Postgres(포스트 그레스) Backend ID(datid)를 System 프로세스 ID와 일치하는 정보는 아래 쿼리 결과를 통해서 실행된 query를 살펴 볼 수 있다.

SELECT pid, datname, usename, query FROM pg_stat_activity
where pid='';

> 실행 결과 예제 ( 구version )

http://dba.stackexchange.com/questions/44084/troubleshooting-high-cpu-usage-from-postgres-and-postmaster-services

* pg_stat_activity 속성

One row per server process, showing information related to the current activity of that process, such as state and current query. See pg_stat_activity for details.

Column	Type	Description
datid	oid	OID of the database this backend is connected to
datname	name	Name of the database this backend is connected to
pid	integer	Process ID of this backend
usesysid	oid	OID of the user logged into this backend
usename	name	Name of the user logged into this backend
application_name	text	Name of the application that is connected to this backend
client_addr	inet	IP address of the client connected to this backend. If this field is null, it indicates either that the client is connected via a Unix socket on the server machine or that this is an internal process such as autovacuum.
client_hostname	text	Host name of the connected client, as reported by a reverse DNS lookup of client_addr. This field will only be non-null for IP connections, and only when log_hostname is enabled.
client_port	integer	TCP port number that the client is using for communication with this backend, or -1 if a Unix socket is used
backend_start	timestamp with time zone	Time when this process was started, i.e., when the client connected to the server
xact_start	timestamp with time zone	Time when this process' current transaction was started, or null if no transaction is active. If the current query is the first of its transaction, this column is equal to the query_start column.
query_start	timestamp with time zone	Time when the currently active query was started, or if state is not active, when the last query was started
state_change	timestamp with time zone	Time when the state was last changed
waiting	boolean	True if this backend is currently waiting on a lock
state	text	Current overall state of this backend. Possible values are: active: The backend is executing a query. idle: The backend is waiting for a new client command. idle in transaction: The backend is in a transaction, but is not currently executing a query. idle in transaction (aborted): This state is similar to idle in transaction, except one of the statements in the transaction caused an error. fastpath function call: The backend is executing a fast-path function. disabled: This state is reported if track_activities is disabled in this backend.
query	text	Text of this backend's most recent query. If state is active this field shows the currently executing query. In all other states, it shows the last query that was executed.

https://www.postgresql.org/docs/9.2/static/monitoring-stats.html