Performance diagnostics in Managed Service for PostgreSQL
Managed Service for PostgreSQL provides a built-in tool for DBMS cluster performance diagnostics. Use it to analyze PostgreSQL performance metrics for sessions and queries.
Enabling statistics collection
Enable the Statistics sampling option when creating a cluster or updating its settings (the option is disabled by default).
If you do not have the Yandex Cloud command line interface yet, install and initialize it.
The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name
or --folder-id
parameter.
To enable statistics collection, pass the --performance-diagnostics
parameter in the update cluster command:
yc managed-postgresql cluster update <cluster_name_or_ID> \
...
--performance-diagnostics enabled=true,`
`sessions-sampling-interval=<session_sampling_interval>,`
`statements-sampling-interval=<statement_sampling_interval> \
...
Acceptable parameter values include:
sessions-sampling-interval
: Between1
and86400
seconds.statements-sampling-interval
: Between60
and86400
seconds.
-
Open the current Terraform configuration file with an infrastructure plan.
For more information about how to create this file, see Creating clusters.
For a complete list of available Managed Service for PostgreSQL cluster configuration fields, see the Terraform provider documentation
. -
To set up statistics collection, to the
config
section, add theperformance_diagnostics
section:resource "yandex_mdb_postgresql_cluster" "<cluster_name>" { ... config { ... performance_diagnostics { enabled = <enables statistics collection: true or false> sessions_sampling_interval = <sessions sampling interval> statements_sampling_interval = <statements sampling interval> } ... } ... }
Where:
enabled
: Enable statistics collection,true
orfalse
.sessions_sampling_interval
: Session sampling interval, from1
to86400
seconds.statements_sampling_interval
: Statement sampling interval, from60
to86400
seconds.
-
Make sure the settings are correct.
-
Using the command line, navigate to the folder that contains the up-to-date Terraform configuration files with an infrastructure plan.
-
Run the command:
terraform validate
If there are errors in the configuration files, Terraform will point to them.
-
-
Confirm updating the resources.
-
Run the command to view planned changes:
terraform plan
If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
-
If you are happy with the planned changes, apply them:
-
Run the command:
terraform apply
-
Confirm the update of resources.
-
Wait for the operation to complete.
-
Time limits
A Terraform provider sets the timeout for Managed Service for PostgreSQL cluster operations:
- Creating a cluster, including restoring from a backup: 30 minutes.
- Editing a cluster: 60 minutes.
- Deleting a cluster: 15 minutes.
Operations exceeding the set timeout are interrupted.
How do I change these limits?Add the
timeouts
block to the cluster description, for example:resource "yandex_mdb_postgresql_cluster" "<cluster_name>" { ... timeouts { create = "1h30m" # 1 hour 30 minutes update = "2h" # 2 hours delete = "30m" # 30 minutes } }
-
To enable statistics collection, use the create or update REST API method for the Cluster resource or the ClusterService/Create or ClusterService/Update gRPC API call and provide the following in the request:
-
Cluster ID in the
clusterId
parameter.You can get the ID with a list of clusters in the folder.
-
true
value in theconfig.performanceDiagnostics.enabled
parameter. -
Sessions sampling interval in the
config.performanceDiagnostics.sessionsSamplingInterval
parameter. Acceptable values are between1
and86400
seconds. -
Statements sampling interval in the
config.performanceDiagnostics.statementsSamplingInterval
parameter. Acceptable values are between60
and86400
seconds. -
List of cluster configuration fields to update in the
updateMask
parameter.
Warning
This API method resets any cluster settings that are not provided explicitly in the request to their defaults. To avoid this, make sure to provide the names of the fields to be changed in the updateMask
parameter.
Getting session statistics
- In the management console
, go to the folder page and select Managed Service for PostgreSQL. - Click the cluster name and select the Performance diagnostics → Sessions tab.
To view session statistics:
- Specify the required time interval.
- (Optional) Set filters.
- Select the required data segment.
To show or hide individual categories, click the category name in the chart legend.
To view the history of queries run during a session:
- Specify the required time interval.
- (Optional) Set filters.
To get statistics for sessions, use the PerformanceDiagnosticsService/ListRawSessionStates gRPC API call and include the following in your request:
-
Cluster ID in the
cluster_id
parameter.You can get the ID with a list of clusters in the folder.
-
Period your request data for:
from_time
: Period startto_time
: Period end
-
Pagination parameters:
page_size
: Maximum number of results per page.page_token
: Token of the previous results page used to get the next page.
For more information about what statistics you can get, see the PostgreSQL documentation
Getting query statistics
- In the management console
, go to the folder page and select Managed Service for PostgreSQL. - Click the cluster name and select the Performance diagnostics → Queries tab.
To view the query statistics for a specific time interval:
- Select the time interval you need.
- (Optional) Set filters.
To get information about the relative change in the query statistics:
- In the Interval 1 field, select the time interval to be used as a calculation basis for statistics.
- In the Interval 2 field, select the time interval to compare the statistics for interval 1 with.
- (Optional) Set filters.
For example, 10 SELECT * FROM cities
queries were executed in the first interval and 20 in the second. When comparing statistics, the difference by the number of queries
metric (the Calls
column in the table) will be +100%
.
To get statistics for queries, use the PerformanceDiagnosticsService/ListRawStatements gRPC API call and include the following in your request:
-
Cluster ID in the
cluster_id
parameter.You can get the ID with a list of clusters in the folder.
-
Period your request data for:
from_time
: Period startto_time
: Period end
-
Pagination parameters:
page_size
: Maximum number of results per page.page_token
: Token of the previous results page used to get the next page.
You can learn more about what statistics you can get in the pg_stat_statements
Getting information about query execution plans
The auto_explain
moduleEXPLAIN
command
To enable query logging, change the DBMS settings:
-
Use the Shared preload libraries field to select the
auto_explain
option. -
Enable the Auto explain log analyze setting.
-
Define the
auto_explain
module settings:Warning
Selecting
0
for Auto explain log min duration or enabling Auto explain log timing can significantly reduce cluster performance.