Version: Cloud

Monitor Postgres DB on Instance

Overview

PostgreSQL on instances is monitored using sfAgent configured with Postgres plugin.

Get Started

To get started with PostgreSQL integration, create a user and grant permissions to collect data from your PostgreSQL server.

Create New User

Create a read-only user with the following command:

create user <username> with password '<password>';

note

Use the username and password created in this section while setting access permission and configuration.

Set Access Permission

For version 10.0 or greater, use the below code to set access permission.

grant SELECT ON pg_stat_database to <username>; 
grant pg_monitor to <username>; 

For older versions, use the below code to set access permission.

grant SELECT ON pg_stat_database to <username>;

note

By default, these permissions are granted to the root user

Prerequisite to Collect Total Query Duration

Execute the following command to check pg_stat_statement is available.

SELECT * FROM pg_available_extensions WHERE name = 'pg_stat_statements' and  installed_version is not null;

If the table is empty, using the following command create the extension.

CREATE EXTENSION pg_stat_statements;
alter system set shared_preload_libraries='pg_stat_statements';

note

Once the extension is added restart the Postgres service using the following command: systemctl restart postgresql.

Configuration

Refer to sfAgent section for steps to install and automatically generate plugin configurations. User can also manually add the configuration shown below to config.yaml under /opt/sfagent/ directory.

key: <profile_key> 
tags: 
  Name: <name> 
  appName: <app_name> 
  projectName: <project_name> 
metrics: 
  plugins: 
    - name: postgres 
      enabled: true 
      interval: 60 
      config: 
        documentsTypes: 
          - databaseDetails 
          - indexDetails 
          - queryDetails 
          - serverDetails 
          - tableDetails 
        host: 127.0.0.1 
        password: <password> 
        port: 5432 
        user: <username> 
logging: 
  plugins: 
    - name: postgres-general 
      enabled: true 
      config: 
        log_level: 
          - error 
          - warning 
          - info 
          - log 
        log_path: /var/log/postgresql/postgresql-10-main.log 
    - name: postgres-slowquery 
      enabled: true 
      config: 
        log_path: /var/log/postgresql/postgresql-10-main.log 

Enable Logs

Enable PostgreSQL general logs

It is required to configure PostgreSQL.conf file to enable PostgreSQL logs. To locate the PostgreSQL.conf, execute the following command:

postgres=# show config_file; 
           config_file             
---------------------------------- 
 /data/pgsql/data/postgresql.conf 
(1 row) 

Update the Postgresql.conf file with the variables shown below:

log_min_messages = warning  # set level as appropriate 
log_line_prefix = '< %m > '

Example:

once the logs are enabled, PostgreSQL general logs will be generated in the below format.

< 2023-05-04 11:52:10.470 IST > LOG:  duration: 1006.577 ms  statement: select pg_sleep(1);

Enable PostgreSQL Slow Query logs

To enable PostgreSQL slow query logs, update the PostgreSQL.conf file with the variables shown below:

log_min_duration_statement = 200

Enable Total Query Duration

To enable PostgreSQL total query duration, update the PostgreSQL.conf file with the variables shown below:

pg_stat_statements.track = all
track_activities = on
track_io_timing = on
track_functions = all     

View Database Metrics and Logs

Go to the Application tab in SnappyFlow and navigate to your Project > Application > Dashboard.
In the dashboard window, click the tab menu ... icon on the Metric section.
Select the Import from template option.
In the Import to Metrics Panes window, select Filter By: Standard, Template Name: PostgreSQL.
Click the Save button.
Database metrics are displayed in the Metrics section of the dashboard.

To view general logs, navigate to Log management > Primary storage.
In the Primary Storage window, set the log filter to a general log as per the requirement.

To view slow query logs, navigate to Metrics > Slow Queries.
To access the unprocessed data gathered from the plugins, navigate to the Browse data section and select the following data:

Index: Metrics
Instance: Select an instance
Plugin: postgres
Document type: serverDetails, databaseDetails, tableDetails, slowqueryDetails, postgres-general, postgres-slowquery, Session Details, checkpointDetails, lockDetails, vaccumDetails

Metric List

Server Details

Metric	Description
numCreatedTempFiles	Total number of temporary files created.
numTransactions	Total number of transactions that have been committed and rolled back.
archiveFailCount	Number of failed attempts for archiving WAL files.
activeProcesses	Number of active process running in the server.
archivedCount	Number of WAL files that have been successfully archived.
numUpdate	Total number of rows updated by queries.
numRollback	Total number of transactions that have been rolled back.
host	The host address of the instance.
cacheHits	Number of times disk blocks were found already in the buffer cache.
idle_in_transaction	Number of idle_in_transaction process running in the server.
numSelect	Total number of live rows fetched by select queries.
maxConnections	The maximum number of concurrent connections to the database server.
tempFileSize	Total amount of data written to temporary files by queries.
idleProcesses	Number of idle process waiting in the server.
numCommit	Total number of transactions that have been committed.
cacheSize	The effective size of the disk cache that is available to a single query.
numConnections	Total number of backends currently connected to this server.
indexSize	Total size of the indices.
bufferSize	Amount of memory the database server uses for shared memory buffers.
dbSize	Total size of the databases.
upTime	Time difference between start time and current time.
abortedConnection	Number of aborted process in the server.
numInsert	Total number of rows inserted by queries in this database.
numDelete	Total number of rows deleted by queries in this database.
cacheHitRatio	Cache Hit Percentage on the server.
numDatabases	Number of Databases.
version	PostgreSQL version of the server.
activeSession	Total number of active sessions.
blockedSession	Total number of blocked sessions.

Database Details

Metric	Description
blkReadTime	Time spent writing data file blocks by backends in this database, in milliseconds.
blocksRead	Number of disk blocks read in this database.
transPerSec	Number of transaction in this database per second.
numDeadTuple	Estimated number of dead rows in database.
numTransactions	Number of transactions in this database that have been committed and rolled back.
numLiveTuple	Estimated number of live rows in database.
numFetch	Number of live rows fetched by index scans in this database.
numRollback	Number of transactions in this database that have been rolled back.
numUpdate	Number of rows updated by queries in this database.
host	The host address of the instance.
numReturn	Number of live rows fetched by sequential scans and index entries returned by index scans in this database.
tempFileSize	Total amount of data written to temporary files by queries in this database.
_dbName	Name of the database.
numCommit	Number of transactions in this database that have been committed.
blocksHit	Number of times disk blocks were found already in the buffer cache, so that a read was not necessary (this only includes hits in the PostgreSQL buffer cache, not the operating system's file system cache).
blkWriteTime	Time spent writing data file blocks by backends in this database, in milliseconds.
numTempFile	Number of temporary files created by queries in this database.
indexSize	Total disk space used by all indexes in the database.
dbSize	Size of the database.
numInsert	Number of rows inserted by queries in this database.
numDelete	Number of rows deleted by queries in this database.
cacheHitRatio	Percentage of cacheHit of this database.
indexHitRatio	Percentage of indexHit of this table.
numTables	Number of tables in this database.

Table Details

Metric	Description
numDeadTuple	Estimated number of dead rows.
numLiveTuple	Estimated number of live rows.
numUpdate	Number of rows updated.
_tableName	Name of the table.
_dbName	Name of the database for this table.
tableSize	Total disk space used by the specified table.
idxBlksRead	Number of disk blocks read from all indexes on this table.
host	The host address of the instance.
seqScan	Number of sequential scans initiated on this table.
indexScanFetch	Number of live rows fetched by index scans.
heapBlksRead	Number of disk blocks read from this table.
idxBlksHit	Number of buffer hits in all indexes on this table.
heapBlksHit	Number of buffer hits in this table.
seqScanFetch	Number of live rows fetched by sequential scans.
indexSize	Total disk space used by indexes attached to the specified table.
numInsert	Number of rows inserted.
indexScan	Number of index scans initiated on this table.
numDelete	Number of rows deleted.
cacheHitRatio	Percentage of cacheHit of this table.
_schemaName	Name of the schema of this table.
indexHitRatio	Percentage of indexHit of this table.

Index Details

Metric	Description
_indexName	Name of this index.
blksHit	Number of buffer hits in this index.
_tableName	Name of the table for this index.
blksRead	Number of disk blocks read from this index.
numFetch	Number of live table rows fetched by simple index scans using this index.
indexScan	Number of index scans initiated on this index.
_schemaName	Name of the schema of this index.
_dbName	Name of the database for this index.
host	The host address of the instance.
numReturn	Number of index entries returned by scans on this index.

Slow Query Details

Metric	Description
runtime	Period of time for the current query is running.
userName	Name of the user logged into this backend.
wait_event	True if backend is currently waiting, otherwise False.
_dbName	Name of the database this backend is connected to.
host	The host address of the instance.
state	Current overall state of this backend. Possible values are: active, idle, idle in transaction, idle in transaction (aborted), fastpath function call, disabled.
_queryName	If state is active this field shows the currently executing query. In all other states, it shows the last query that was executed.

Session Details

Metric	Description
blockedSession	Total number of blocked sessions.
totalqueryDuration	The total duration of active sessions in PostgreSQL database.
averageDuration	The average duration of active sessions in PostgreSQL database.
sessionperuser	Count or frequency of sessions associated with each user.
sessionperDatabase	The host address of the instance.
sessionperHost	Count of sessions associated with each host.
sessionperApplication	Count of sessions associated with each application.
connectionperDatabase	Count of sessions associated with each database.
PID	PID assigned to the session.
username	User associated with the session.
client_addr	IP address or hostname of the client machine initiating the session.
application	Name or identifier of the client application establishing the session.
backend_start	Timestamp indicating when the session was established.
state	Current state of the session, such as "idle", "active", "idle in transaction", "idle in transaction (aborted)", etc.
stateChange	Timestamp when the state of a session transitions from one state to another.

Checkpoint Details

Metric	Description
checkpointSegments	Number of checkpoints performed based on the checkpoint_timeout.
checkpointBuffersAlloc	Number of buffers allocated for database operations.
checkpointBuffersClean	Number of buffers written by backends during normal database operations.
checkpointBuffersBackendFsync	Number of times a backend had to execute its own sync call (normally the background writer handles those even when the backend does its own write).

Vacuum Details

Metric	Description
autovacuumStatus	Automatic maintenance process is enabled or not.
numOfVacuumProgress	if vaccum is running, the pg_stat_progress_vacuum view will contain one row for each backend (including autovacuum worker processes) that is currently vacuuming.

Lock Details

Metric	Description
Database	Database to which the lock belongs.
lockMode	Type of lock mode (AccessShareLock, RowShareLock,etc).
lockStatus	Lock is granted or not.
waitEvent	Type of wait event.
lockType	The type of lock being held, such as relation, transactionid, virtualxid, object, extend, page, tuple, etc.
processID	Process ID of the session holding the lock.
relationName	Relation (table, index, etc.) on which the lock is held.

Monitor Postgres DB on Instance

Overview​

Get Started​

Create New User​

Set Access Permission​

Prerequisite to Collect Total Query Duration​

Configuration​

Enable Logs​

Enable PostgreSQL general logs​

Enable PostgreSQL Slow Query logs​

Enable Total Query Duration​

View Database Metrics and Logs​

Metric List​

Server Details​

Database Details​

Table Details​

Index Details​

Slow Query Details​

Session Details​

Checkpoint Details​

Vacuum Details​

Lock Details​

Overview

Get Started

Create New User

Set Access Permission

Prerequisite to Collect Total Query Duration

Configuration

Enable Logs

Enable PostgreSQL general logs

Enable PostgreSQL Slow Query logs

Enable Total Query Duration

View Database Metrics and Logs

Metric List

Server Details

Database Details

Table Details

Index Details

Slow Query Details

Session Details

Checkpoint Details

Vacuum Details

Lock Details