Use query insights to improve query performance

This page describes how to use the Query insights dashboard to detect and analyze performance problems.

You can use Gemini in Databases assistance to help you observe and troubleshoot your Cloud SQL for PostgreSQL resources. For more information, see Observe and troubleshoot with Gemini assistance.

Introduction

Query insights helps you detect, diagnose, and prevent query performance problems for Cloud SQL databases. It supports intuitive monitoring and provides diagnostic information that helps you go beyond detection to identify the root cause of performance problems.

With query insights, you can monitor performance at an application level and trace the source of a problematic query across the application stack by model, view, controller, route, user, and host. The query insights tool can integrate with your existing application monitoring (APM) tools and Google Cloud services by using open standards and APIs. This way, you can monitor and troubleshoot query problems by using your favorite tool.

Query insights helps you improve Cloud SQL query performance by guiding you through the following steps:

Query insights for Cloud SQL Enterprise Plus edition

If you're using Cloud SQL Enterprise Plus edition, then you can access additional capabilities in query insights to perform advanced query performance diagnostics. In addition to the standard capabilities of the Query insights dashboard, query insights for Cloud SQL Enterprise Plus edition lets you do the following:

  • Capture and analyze wait events for all executed queries
  • Filter aggregated database load by additional dimensions such as queries, tags, wait event types, and more
  • Capture query plans for all executed queries
  • Sample up to 200 query plans per minute
  • Capture longer query text up to 100 KB
  • Obtain near real-time updates for metrics (in the order of seconds)
  • Maintain a longer 30-day retention of metrics

The following table compares functional requirements and capabilities of query insights for Cloud SQL Enterprise edition with query insights for Cloud SQL Enterprise Plus edition.

Comparison area Query insights for Cloud SQL Enterprise edition Query insights for Cloud SQL Enterprise Plus edition
Supported database versions PostgreSQL 9.6 or later PostgreSQL 12 or later
Supported machine types Supported on all machine types Not supported on instances that use a shared core machine type or on read replica instances
Supported regions Cloud SQL regional locations Cloud SQL Enterprise Plus edition regional locations
Metrics retention period 7 days 30 days
Query length limit maximum 4500 bytes 100 KB
Query plan sample maximum 20 200
Wait event analysis Not available Available

To enable query insights for Cloud SQL Enterprise Plus edition during Preview for your Cloud SQL Enterprise Plus edition instance, follow the steps in Enable query insights for Cloud SQL Enterprise Plus edition.

Pricing

There's no additional cost for query insights. In addition, there's no cost for enabling query insights for Cloud SQL Enterprise Plus edition, which is in Preview.

Storage requirements

Query insights for Cloud SQL Enterprise edition doesn't occupy any storage space in your Cloud SQL instance storage space. Metrics are stored in Cloud Monitoring. For API requests, see Cloud Monitoring Pricing. Cloud Monitoring has a tier that you can use at no additional cost.

Query insights for Cloud SQL Enterprise Plus edition (Preview) stores metrics data on the same disk attached to your Cloud SQL instance and requires that you keep the automatic storage increases setting enabled.

The storage requirement for seven days worth of data is approximately 36 GB. For 30 days, you need approximately 155 GB. Query insights for Cloud SQL Enterprise Plus edition uses up to 10 MB of RAM (shared memory). Metrics are expected to be available in query insights within 30 seconds of query completion. Applicable storage fees apply.

Before you begin

Before you use query insights, do the following.

  1. Add required roles and permissions.
  2. Enable the Cloud Trace API.
  3. If you're using Query insights for Cloud SQL Enterprise Plus edition, then make sure that Enable automatic storage increases is enabled for the instance.

Required roles and permissions

To use query insights, you need to grant roles with the required Identity and Access Management permissions or provide a user account with the required permissions.

For more information about granting roles, see Manage access.

To get the permissions that you need to access historical query execution data in the Query insights dashboard, ask your administrator to grant you the following IAM roles on the project that hosts the Cloud SQL instance:

For more information about granting roles, see Manage access to projects, folders, and organizations.

These predefined roles contain the permissions required to access historical query execution data in the Query insights dashboard. To see the exact permissions that are required, expand the Required permissions section:

Required permissions

The following permissions are required to access historical query execution data in the Query insights dashboard:

  • databaseinsights.aggregatedStats.query
  • databaseinsights.timeSeries.query

You might also be able to get these permissions with custom roles or other predefined roles.

For example, in Database Insights, you can ask your administrator to grant you the Database Insights Viewer (roles/databaseinsights.viewer) predefined role. Then, in Cloud SQL, you can ask your administrator to grant you one of the following predefined roles:

Enable the Trace API

To view query plans and their end-to-end views, your Google Cloud project must have the Trace API enabled. This setting lets your Google Cloud project receive trace data from authenticated sources at no additional cost. This data can help you detect and diagnose performance issues in your instance.

To confirm that the Trace API is enabled, follow these steps:

  1. From the Google Cloud console, go to APIs and Services:

    Go to APIs and Services

  2. Click Enable APIs and Services.
  3. In the search bar, enter Trace API.
  4. If API enabled is displayed, then this API is enabled and there's nothing for you to do. Otherwise, click Enable.

Enable automatic storage increases

If you're using Query insights for Cloud SQL Enterprise Plus edition (Preview), then make sure that the instance setting to enable automatic storage increases remains enabled. By default, this option is enabled for Cloud SQL instances.

If you previously disabled this instance setting and want to enable Query insights for Cloud SQL Enterprise Plus edition, then re-enable automatic storage increases first. You can't turn off automatic storage increases and enable Query insights for Cloud SQL Enterprise Plus edition.

Enable query insights

Users who have access to the Cloud SQL dashboard can access query insights metrics. If you have permission to update instances, then you can enable query insights. For a list of permissions required for Cloud SQL instances, see Cloud SQL project access control. If you don't have these permissions and you want to enable query insights on your instances, then contact your administrator.

Console

Enable query insights for an instance

  1. In the Google Cloud console, go to the Cloud SQL Instances page.

    Go to Cloud SQL Instances

  2. To open the Overview page of an instance, click the instance name.
  3. On the Configuration tile, click Edit configuration.
  4. In the Customize your instance section, expand Query insights.
  5. Select the Enable Query insights checkbox.
  6. Optional. Select one or more of the following query insights additional features:
  7. Active query analysis

    Default: false

    Lets you review details about your actively running queries and if necessary, terminate long-running queries. For more information, see Monitor active queries. This feature is in Preview.

    Enable index advisor

    Default: false

    Index advisor provides index recommendations to speed up query processing. When you enable index advisor, your instance requires a restart. For more information, see Index advisor overview and Use index advisor. This feature is in Preview.

    Store client IP addresses

    Default: false

    Stores the client IP addresses where queries are coming from and helps you group that data to run metrics against it. Queries come from more than one host. Reviewing graphs for queries from client IP addresses can help identify the source of a problem.

    Store application tags

    Default: false

    Stores application tags that help you determine the APIs and model-view-controller (MVC) routes that are making requests and group the data to run metrics against it. This option requires you to comment queries with a specific set of tags using the sqlcommenter open source object-relational mapping (ORM) auto-instrumentation library. This information helps query insights identify the source of a problem and the MVC from which the problem is coming. Application paths help you with application monitoring.

    Customize query lengths

    Default: 1024

    Sets the query length limit to a specified value from 256 bytes to 4500 bytes. Higher query lengths are more useful for analytical queries, but they also require more memory. Changing the query length requires you to restart the instance. You can still add tags to queries that exceed the length limit.

    Set the maximum sampling rate

    Default: 5

    Sets the maximum sampling rate. Sampling rate is the number of executed query plan samples that are captured per minute across all databases on the instance. Change this value to a number from 0 (setting this value to 0 disables sampling) to 20. Increasing the sampling rate is likely to give you more data points but might increase performance overhead.

  8. Click Save.

Enable query insights for multiple instances

  1. In the Google Cloud console, go to the Cloud SQL Instances page.

    Go to Cloud SQL Instances

  2. Click the More Actions menu on any row.
  3. Select Enable Query insights.
  4. In the dialog, select the Enable Query insights for multiple instances checkbox.
  5. Click Enable.
  6. In the subsequent dialog, select the instances for which you want to enable query insights.
  7. Click Enable Query insights.

gcloud

To enable query insights for a Cloud SQL instance by using gcloud, run gcloud sql instances patch with the --insights-config-query-insights-enabled flag as follows after replacing INSTANCE_ID with the ID of the instance.

    gcloud sql instances patch INSTANCE_ID \
    --insights-config-query-insights-enabled
  

Also, use one or more of the following optional flags:

  • --insights-config-record-client-address

    Stores the client IP addresses where queries are coming from and helps you group that data to run metrics against it. Queries come from more than one host. Reviewing graphs for queries from client IP addresses can help identify the source of a problem.

  • --insights-config-record-application-tags

    Stores application tags that help you determine the APIs and model-view-controller (MVC) routes that are making requests and group the data to run metrics against it. This option requires you to comment queries with a specific set of tags. You can do this by using the sqlcommenter open source object-relational mapping (ORM) auto-instrumentation library. This information helps Query Insights identify the source of a problem and the MVC the problem is coming from. Application paths help you with application monitoring.

  • --insights-config-query-string-length

    Sets the default query length limit to a specified value from 256 to 4500 bytes. The default query length is 1024 bytes. Higher query lengths are more useful for analytical queries, but they also require more memory. Changing the query length requires you to restart the instance. You can still add tags to queries that exceed the length limit.

  • --query_plans_per_minute

    By default, a maximum of 5 executed query plan samples are captured per minute across all databases on the instance. Change this value to a number from 0 (setting this value to 0 disables sampling) to 20. Increasing the sampling rate is likely to give you more data points but might add a performance overhead.

Replace the following:

  • INSIGHTS_CONFIG_QUERY_STRING_LENGTH: The query string length to be stored, in bytes.
  • API_TIER_STRING: The custom instance configuration to use for the instance.
  • REGION: The region for the instance.
gcloud sql instances patch INSTANCE_ID \
--insights-config-query-insights-enabled \
--insights-config-query-string-length=INSIGHTS_CONFIG_QUERY_STRING_LENGTH \
--query_plans_per_minute=QUERY_PLANS_PER_MINUTE \
--insights-config-record-application-tags \
--insights-config-record-client-address \
--tier=API_TIER_STRING \
--region=REGION
  

REST v1

To enable query insights for a Cloud SQL instance by using the REST API, call the instances.patch method with insightsConfig settings.

Before using any of the request data, make the following replacements:

  • project-id: The project ID.
  • instance-id: The instance ID.

HTTP method and URL:

PATCH https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id

Request JSON body:

{
  "settings" : { "insightsConfig" : { "queryInsightsEnabled" : true } }
}

To send your request, expand one of these options:

You should receive a JSON response similar to the following:

{
  "kind": "sql#operation",
  "targetLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id",
  "status": "PENDING",
  "user": "user@example.com",
  "insertTime": "2021-01-28T22:43:40.009Z",
  "operationType": "UPDATE",
  "name": "operation-id",
  "targetId": "instance-id",
  "selfLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/operations/operation-id",
  "targetProject": "project-id"
}

Terraform

To use Terraform to enable query insights for a Cloud SQL instance, set the query_insights_enabled flag to true.

Also, you can use one or more of the following optional flags:

  • query_string_length: Default is 1024 and you can configure it to a value between 256 and 4500 in bytes.
  • record_application_tags: Set the value to true if you want to record application tags from the query.
  • record_client_address: Set the value to true if you want to record the client IP address.
  • query_plans_per_minute: Default is 5 and you can configure it to a value between 5 and 20.

Here's an example:

  resource "google_sql_database_instance" "INSTANCE_NAME" {
  name                = "INSTANCE_NAME"
  database_version    = "POSTGRESQL_VERSION"
  region              = "REGION"
  root_password       = "PASSWORD"
  deletion_protection = false # set to true to prevent destruction of the resource
  settings {
    tier = "DB_TIER"
    insights_config {
      query_insights_enabled  = true
      query_string_length     = 2048 # Optional
      record_application_tags = true # Optional
      record_client_address   = true # Optional
      query_plans_per_minute  = 10 # Optional
    }
  }
  }
  

To apply your Terraform configuration in a Google Cloud project, complete the steps in the following sections.

Prepare Cloud Shell

  1. Launch Cloud Shell.
  2. Set the default Google Cloud project where you want to apply your Terraform configurations.

    You only need to run this command once per project, and you can run it in any directory.

    export GOOGLE_CLOUD_PROJECT=PROJECT_ID

    Environment variables are overridden if you set explicit values in the Terraform configuration file.

Prepare the directory

Each Terraform configuration file must have its own directory (also called a root module).

  1. In Cloud Shell, create a directory and a new file within that directory. The filename must have the .tf extension—for example main.tf. In this tutorial, the file is referred to as main.tf.
    mkdir DIRECTORY && cd DIRECTORY && touch main.tf
  2. If you are following a tutorial, you can copy the sample code in each section or step.

    Copy the sample code into the newly created main.tf.

    Optionally, copy the code from GitHub. This is recommended when the Terraform snippet is part of an end-to-end solution.

  3. Review and modify the sample parameters to apply to your environment.
  4. Save your changes.
  5. Initialize Terraform. You only need to do this once per directory.
    terraform init

    Optionally, to use the latest Google provider version, include the -upgrade option:

    terraform init -upgrade

Apply the changes

  1. Review the configuration and verify that the resources that Terraform is going to create or update match your expectations:
    terraform plan

    Make corrections to the configuration as necessary.

  2. Apply the Terraform configuration by running the following command and entering yes at the prompt:
    terraform apply

    Wait until Terraform displays the "Apply complete!" message.

  3. Open your Google Cloud project to view the results. In the Google Cloud console, navigate to your resources in the UI to make sure that Terraform has created or updated them.

Metrics are expected to be available in query insights within minutes of query completion. Review the Cloud Monitoring data retention policy.

Query insights traces are stored in Cloud Trace. Review the Cloud Trace data retention policy.

Enable query insights for Cloud SQL Enterprise Plus edition

You can enable query insights for Cloud SQL Enterprise Plus edition on your Cloud SQL instance only by using the Google Cloud console.

  1. In the Google Cloud console, go to the Cloud SQL Instances page.

    Go to Cloud SQL Instances

  2. To open the Overview page of an instance, click the instance name.
  3. Click Edit.
  4. In the Storage section, verify that Enable automatic storage increases checkbox is selected.
  5. In the Customize your instance section, expand Query insights.
  6. Select the Enable Enterprise Plus features checkbox.
  7. After you enable query insights for Cloud SQL Enterprise Plus edition, you can update the following fields:

    • Customize query lengths: specify the limit, in bytes, of the query length. You can specify a number from 1024 to 100000. Any query string that goes above the specified limit becomes truncated in the display. A higher query length limit requires more memory. The default value is 10000 bytes.

      By default, the maximum sample rate is 200 query plan samples per minute across all databases on the instance.

  8. Click Save.

View the Query insights dashboard

The Query insights dashboard shows the query load based on factors that you select. Query load is a measurement of the total work for all the queries in the instance in the selected time range. The dashboard provides a series of filters that help you view query load.

To open the Query insights dashboard, follow these steps:

  1. To open the Overview page of an instance, click the instance name.
  2. Either select the Query insights tab in the left navigation panel or click the Go to Query insights for more in-depth info on queries and performance link.

The Query insights dashboard opens. It shows the following information about your instance:

Shows the Query insights dashboard, with drop-down menus
         for databases, users, and addresses. To the right of the drop-down
         menus, there's a filter for setting a time range. Also,
         a graph shows the database load for top queries. At the bottom
         of the graph, there are selection boxes for CPU capacity, CPU and
         CPU wait, IO Wait, and Lock Wait and a tab each for queries and tags.

  • Databases: Filters query load on a specific database or all databases.
  • User: Filters query load from a specific user account.
  • Client address: Filters query load from a specific IP address.
  • Time range: Filters query load by time ranges, such as 1 hour, 6 hours, 1 day, 7 days, 30 days, or a custom range.
  • Database load graph: Displays the query load graph, based on filtered data.
  • CPU capacity, CPU and CPU wait, IO wait, and Lock wait: Filters loads based on the options that you select. See View the database load for top queries for details about each of these filters.
  • Queries and Tags: Filters query load by either a selected query or a selected SQL query tag. See Filter the database load.

View the database load for all queries

Database query load is a measure of the work (in CPU seconds) that the executed queries in your selected database perform over time. Each running query is either using or waiting for CPU resources, IO resources, or lock resources. Database query load is the ratio of the amount of time taken by all the queries that are completed in a given time window to the wall-clock time.

The top-level query insights dashboard shows the Database load — all top queries graph. Drop-down menus on the dashboard let you filter the graph for a specific database, user, or client address.

Shows the database load graph with a load for CPU capacity, CPU and
         CPU wait, IO Wait, and Lock Wait.

Colored lines in the graph show the query load, split into categories:

  • CPU capacity: The number of CPUs available on the instance.
  • CPU and CPU Wait: The ratio of the time taken by queries in an active state to wall-clock time. IO and Lock waits don't block queries that are in an active state. This metric might mean that the query is either using the CPU or waiting for the Linux scheduler to schedule the server process running the query while other processes are using the CPU.
  • IO Wait: The ratio of time taken by queries that are waiting for IO to wall-clock time. IO wait includes Read IO Wait and Write IO Wait. If you want a breakdown of information for IO waits, you can see it in Cloud Monitoring. See Cloud SQL metrics for more information. For more information, see the PostgreSQL event table.
  • Lock Wait: The ratio of time taken by queries that are waiting for Locks to wall-clock time. It includes Lock Waits, LwLock Waits, and Buffer pin Lock waits. To see a breakdown of information for lock waits, use Cloud Monitoring. See Cloud SQL metrics for more information.

Colored lines in the graph show per database load by execution time. Review the graph and use the filtering options to explore these questions:

  • Is the query load high? Is the graph spiking or elevated over time? If you don't see a high load, then the problem isn't with your query.
  • How long has the load been high? Is it high only now or has it been high for a long time? Use the range selector to select various time periods to find out how long the problem has lasted. Zoom in to view a time window where query load spikes are observed. Zoom out to view up to one week of the timeline.
  • What's causing the high load? You can select options to examine the CPU capacity, CPU and CPU wait, Lock wait, or IO wait. The graph for each of these options is a different color so that you can spot the one with the highest load. The dark blue line on the graph shows the maximum CPU capacity of the system. It lets you compare the query load with the maximum CPU system capacity. This comparison helps you determine whether an instance is running out of CPU resources.
  • Which database is experiencing the load? Select different databases from the Databases drop-down menu to find the databases with the highest loads.
  • Do specific users or IP addresses cause higher loads? Select different users and addresses from the drop-down menus to identify the ones that are causing higher loads.

Filter the database load

You can filter the database load by queries or tags. If you're using query insights for Cloud SQL Enterprise Plus edition, then you can customize the database load chart to break down the displayed data using any of the following dimensions:

  • All queries
  • Wait event types

  • Wait events

  • Databases

  • Users

  • Tags

  • Client addresses

To customize the database load chart, select a dimension from the Database Load by execution time drop-down.

View the top contributors to database load

To view the top contributors to the database load, you can use the Top dimensions by database load table. The Top dimensions by database load table displays the top contributors for the time period and dimension that you select in the Database Load by execution time chart drop-down. You can modify the time period or dimension to view the top contributors for a different dimension or time period.

In the Top dimensions by data load table, you can select the following tabs.

Tab Description
Queries The table displays the top normalized queries by total execution time. For each query, the data shown in columns are listed as follows:
  • Avg execution time (ms): average time for the query to execute.
  • Total execution time (ms): the total execution time taken by the specific query.
  • Avg rows returned: the average number of rows fetched for the query.
  • Times called: the number of times the query was called by the application.
  • %load by SELECTED_DIMENSION: the percentage line chart depicts how the selected dimension is distributed for the specific query.
Wait event types The table displays the list of top wait event types that occurred during the selected time period. This table is only available for query insights for Cloud SQL Enterprise Plus edition.
  • Avg time spent in wait (ms): average time the queries spent in the specific wait event type.
  • Total time spent in wait (ms): the total execution time the queries spent in the specific wait event type.
  • Wait event type count: the number of times a specific wait event type occurred in the selected time period.
  • %load by SELECTED_DIMENSION: the percentage line chart depicts how the dimension selected for the database load chart is distributed for the specific wait event type.
Wait events The table displays the list of top wait events that occurred during the selected time period. This table is only available for query insights for Cloud SQL Enterprise Plus edition.
  • Avg time spent in wait (ms): average time the queries spent in the specific wait event.
  • Total time spent in wait (ms): the total execution time the queries spent in the specific wait event.
  • Wait event count: the number of times a specific wait event type occurred in the selected time period.
  • %load by SELECTED_DIMENSION: the percentage line chart depicts how the dimension selected for the database load chart is distributed for the specific wait event.
Databases The table shows the list of top databases that contributed to the load during the chosen time period across all executed queries.
  • Avg time spent in database (ms): average time the queries spent in the specific database.
  • Total time spent in database (ms): the total execution time the queries spent in the specific database.
  • %load by SELECTED_DIMENSION: the percentage line chart depicts how the dimension selected for the database load chart is distributed across the specific database.
Users The table shows the list of top users for the selected time period across all executed queries.
  • Avg time spent in user (ms): average time the queries spent on the specific user.
  • Total time spent in user (ms).: the total execution time the queries spent in the specific user.
  • %load by SELECTED_DIMENSION: the percentage line chart depicts how the dimension selected for the database load chart is distributed across the specific user.
Tags For information about tags, Filter by query tags.
Client addresses The table shows the list of top users for the selected time period across all executed queries.
  • Total time spent in client address (ms): the total execution time the queries spent for a specific client.
  • %load by SELECTED_DIMENSION: the percentage line chart depicts how the dimension selected for the database load chart is distributed across the specific client.

Filter by queries

The Queries table provides an overview of the queries that cause the most query load. The table shows all the normalized queries for the time window and options selected on the Query insights dashboard. It sorts queries by the total execution time during the time window that you selected.

Shows the database load graph with a load for queries, with
         filters selected for CPU capacity, CPU and
         CPU wait, IO Wait, and Lock Wait.

To sort the table, select a column heading or a property from Filter queries. The table shows the following properties:

  • Query: the normalized query string. By default, Query insights shows only 1024 characters in the query string. Queries labeled UTILITY COMMAND usually include BEGIN, COMMIT, and EXPLAIN commands or wrapper commands.
  • Database: the database against which the query was run.
  • Load by total time/Load by CPU/Load by IO wait/Load by lock wait: The options by which you can filter specific queries to find the largest load.
  • % load by queries: The percentage load by individual query.
  • Avg execution time (ms): The average time for the query to execute.
  • Times called: the number of times the application called the query.
  • Avg rows returned: the average number of rows returned for the query.

Query insights stores and displays only normalized queries.

By default, query insights doesn't collect IP addresses or tag information. You can enable query insights to collect this information and, when required, disable collection.

Query plan traces don't collect or store any constant values and removes any PII information that the constant might show.

For PostgreSQL 9.6 and 10, query insights displays normalized queries, that is, ? replaces the literal constant value. In the following example, the name constant is removed and ? replaces it.

  UPDATE
    "demo_customer"
  SET
    "customer_id" = ?::uuid,
    "name" = ?,
    "address" = ?,
    "rating" = ?,
    "balance" = ?,
    "current_city" = ?,
    "current_location" = ?
  WHERE
    "demo_customer"."id" = ?
  

For PostgreSQL version 11 and later, $1, $2, and similar variables replace literal constant values.

  UPDATE
    "demo_customer"
  SET
    "customer_id" = $1::uuid,
    "name" = $2,
    "address" = $3,
    "rating" = $4,
    "balance" = $5,
    "current_city" = $6,
    "current_location" = $7
  WHERE
    "demo_customer"."id" = $8
  

Filter by query tags

To troubleshoot an application, you must first add tags to your SQL queries. Query load tags provide a breakdown of the query load of the selected tag over time.

Query insights provides application-centric monitoring to diagnose performance problems for applications built using ORMs. If you're responsible for the entire application stack, query insights provides query monitoring from an application view. Query tagging helps you find issues at higher-level constructs, such as with the business logic or a microservice.

You might tag queries by the business logic, for example, the payment, inventory, business analytics, or shipping tags. You can then find the query load that the various business logic create. For example, you might observe unexpected events, such as spikes for a business analytics tag at 1 PM or unexpected growth for a payment service trending over the previous week.

To calculate the Database load for tag, query insights uses the amount of time taken by every query that uses the tag that you select. The tool calculates the completion time at the minute boundary by using wall-clock time.

On the query insights dashboard, to view the tags table, select Tags. The table sorts tags by their total load by total time.

Shows the Query Insights dashboard, with load for tags and a list of tags.

You can sort the table by selecting a property from Filter tags, or by clicking a column heading. The table shows the following properties:

  • Action, Controller, Framework, Route, Application, DB driver: Each property that you added to your queries appears as a column. At least one of these properties must be added if you want to filter by tags.
  • Load by total time/Load by CPU/Load by IO wait/Load by lock wait: Options to filter specific queries to find the largest load for each option.
  • Avg execution time (ms): The average time for the query to run.
  • Avg rows returned: The average number of rows returned for the query.
  • Times called: The number of times the application called the query.
  • Database: The database against which the query was run.

Examine a specific query or tag

To determine whether a query or a tag is the root cause of the problem, do the following from the Queries tab or Tags tab, respectively:

  1. To sort the list in descending order, click the Load by total time header.
  2. Click the query or tag at the top of the list. It has the highest load and is taking more time than the others.

A dashboard opens showing the details of the selected query or tag.

Examine a specific query load

The dashboard for a selected query appears as follows:

Shows the database load and latency graphs for a
         specific query.

The Database load — specific query graph shows a measure of the work (in CPU seconds) that your normalized query has performed in your selected query over time. To calculate load, it uses the amount of time taken by the normalized queries that are completed at the minute boundary to the wall-clock time. At the top of the table, the first 1024 characters of the normalized query, with literals removed for aggregation and PII reasons, are displayed.

Shows the database load graph with a load for a specific query, with
         filters selected for CPU capacity, CPU and CPU wait, IO wait, and Lock
         wait.

As with the total queries graph, you can filter the load for a specific query by Database, User, and Client address. Query load is split into CPU capacity, CPU and CPU wait, IO wait, and Lock wait.

Examine a specific tagged query load

The dashboard for a selected tag appears as follows. For example, if all queries from a microservices payment are tagged as payment, you can see the amount of query load that's trending by viewing the tag payment.

Shows the database load and latency graphs on the page for a
         specific tag.

The Database load — specific tags graph shows a measure of the work (in CPU seconds) that queries matching your selected tags have performed in your selected database over time. As with the total queries graph, you can filter the load for a specific tag by Database, User, and Client address.

Examine operations in a sampled query plan

A query plan takes a sample of your query and breaks it down into individual operations. It explains and analyzes each operation in the query.

The Query plan samples graph shows all the query plans running at particular times and the amount of time each plan took to run. You can change the rate at which query plan samples are captured per minute. See Enable Query Insights.

A graph for sample query plans, with the time when they
         were run at the bottom of the graph (x axis) and the number of seconds
         they ran on the right (y axis).

By default, the panel on the right shows the details for the sample query plan that takes the longest time, as visible on the Query plan samples graph. To see the details for another sample query plan, click the relevant circle on the graph. Expanded details show a model of all the operations in the query plan. Each operation shows the latency, rows returned, and the cost of the operation. When you select an operation, you can see more details, such as shared hit blocks, the type of schema, loops, and plan rows.

The query plan shows the latency and cost for each operation
         run for the query. It starts with an aggregate, which returns 48 rows,
         with a latency of 31.06 ms and a cost. of 296.34. The next operation is
         a nested loop, which splits into another nested loop and a materialize.
         The nested loop splits into another nested loop and an index scan. The
         materialize leads to a sequence scan.

Try to narrow down the problem by looking into the following questions:

  1. What's the resource consumption?
  2. How does it relate to other queries?
  3. Does consumption change over time?

Examine latency

Latency is the time taken for the normalized query to complete, in wall-clock time. You use the Latency graph to examine latency on the query or tag. The latency dashboard shows the 50th, 95th, and 99th percentile latencies to find outlier behaviors.

The following image shows the database load graph at the 50th percentile for a specific query with filters selected for CPU capacity, CPU and CPU wait, IO wait, and Lock wait.

Shows the query latency graph for a specific
         query with filters selected for CPU capacity, CPU and CPU wait,
         IO wait, and Lock wait.

The latency of parallel queries is measured in wall-clock time even though the query load can be higher for the query due to multiple cores being used to run part of the query.

Try to narrow down the problem by looking into the following questions:

  • What's causing the high load? Select options to look at the CPU capacity, CPU and CPU wait, I/O wait, or Lock wait.
  • How long has the load been high? Is it only high now? Or has it been high for a long time? Change the time range to find the date and time that the load started performing poorly.
  • Were there spikes in latency? Change the time window to study the historical latency for the normalized query.

Trace the source of the problem

When you find the areas and times where the load was the highest, identify the source of the problem by using tracing to drill down further.

To help you identify the specific source of the problem, such as a model, view, controller, route, host, or user, query insights provides an in-context end-to-end application trace view. This view helps you understand what's going on at the Database Layer for a specific request and to find the source of a problematic query by model, view, controllers, and route.

If you enable OpenCensus or OpenTelemetry, opencensus span information is sent to the database along with the tag information inside SQL comments. Any traces from the application to Cloud Logging are linked with database query plan traces to help identify the source of the problem.

Click the End to end tab in the Sample Query screen to look at the in-context trace.

Select an End-to-end tag to view specific information
         about the tag. The Summary shows the RPCs and Total Duration in ms for
         each operation for that tag.

To determine the client and user causing the problem, use the Top client addresses and Top users tables to find the highest loads. You can add a user or IP address to the filter to further analyze a specific user or client address. The details in the tables include the percentage of the query load, the average execution time in milliseconds, and the times called.

The image shows that for top client addresses, the load was
         100%, the average execution time was 19,568 seconds, and the times
         called was 1,226. For top users, the user postgres had 100% of the load,
         had an average execution time of 19,568 ms, and was called 1,226
         times.

You can use Cloud Trace to see end-to-end tracing for each step in the query plan. On the query insights dashboard, click the View in trace link to open the Cloud Trace tool. The trace graph shows all the traces that have been run for the selected period.

The trace graph shows all the traces that have been run for
         the selected period, in this case, one hour. The
         page also has a table that shows latency, HTTP method, URL, and the
         time when the trace was run.cd

For details, see Finding and viewing traces.

Add tags to SQL queries

Tagging SQL queries simplifies application troubleshooting. You can use sqlcommenter to add tags to your SQL queries either automatically or manually.

Use sqlcommenter with ORM

When you use ORM instead of directly writing SQL queries, you might not find application code that's causing performance challenges. You might also have trouble analyzing how your application code affects query performance. To tackle this issue, Query Insights provides an open source library called sqlcommenter. This library is useful for developers and administrators using ORM tools to detect which application code is causing performance problems.

If you're using ORM and sqlcommenter together, the tags are automatically created. You don't need to add or change code in your application.

You can install sqlcommenter on the application server. The instrumentation library allows application information related to your MVC framework to be propagated to the database along with the queries as a SQL comment. The database picks up these tags and starts recording and aggregating statistics by tags, which are orthogonal to statistics aggregated by normalized queries. Query insights shows the tags so that you know which application is causing the query load and can find the application code that's causing performance problems.

When you examine results in SQL database logs, they appear as follows:

    SELECT * from USERS /action='run+this',
    controller='foo%3',
    traceparent='00-01',
    tracestate='rojo%2'/
  

Supported tags include the controller name, route, framework, and action.

The set of ORM tools in sqlcommenter is supported for the following programming languages:

Python
  • Django
  • psycopg2
  • Sqlalchemy
  • Flask
Java
  • Hibernate
  • Spring
Ruby
  • Rails
Node.js
  • Knex.js
  • Sequelize.js
  • Express.js

For more information about sqlcommenter and how to use it in your ORM framework, see the sqlcommenter documentation.

Use sqlcommenter to add tags

If you're not using ORM, you must manually add sqlcommenter tags or comments in the correct SQL comment format to your SQL query. You must also augment each SQL statement with a comment containing a serialized key-value pair. Use at least one of the following keys:

  • action=''
  • controller=''
  • framework=''
  • route=''
  • application=''
  • db driver=''

Query insights drops all other keys.

Disable query insights

Console

To disable query insights for a Cloud SQL instance by using the Google Cloud console, follow these steps:

  1. In the Google Cloud console, go to the Cloud SQL Instances page.

    Go to Cloud SQL Instances

  2. To open the Overview page of an instance, click the instance name.
  3. On the Configuration tile, click Edit configuration.
  4. In the Configuration options section, expand Query insights.
  5. Clear the Enable Query insights checkbox.
  6. Click Save.

gcloud

To disable query insights for a Cloud SQL instance by using gcloud, run gcloud sql instances patch with the --no-insights-config-query-insights-enabled flag as follows, after replacing INSTANCE_ID with the ID of the instance.

gcloud sql instances patch INSTANCE_ID 
--no-insights-config-query-insights-enabled

REST

To disable query insights for a Cloud SQL instance by using the REST API, call the instances.patch method with queryInsightsEnabled set to false as follows.

Before using any of the request data, make the following replacements:

  • project-id: The project ID.
  • instance-id: The instance ID.

HTTP method and URL:

PATCH https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id

Request JSON body:

{
  "settings" : { "insightsConfig" : { "queryInsightsEnabled" : false } }
}

To send your request, expand one of these options:

You should receive a JSON response similar to the following:

{
  "kind": "sql#operation",
  "targetLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id",
  "status": "PENDING",
  "user": "user@example.com",
  "insertTime": "2021-01-28T22:43:40.009Z",
  "operationType": "UPDATE",
  "name": "operation-id",
  "targetId": "instance-id",
  "selfLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/operations/operation-id",
  "targetProject": "project-id"
}

Disable query insights for Cloud SQL Enterprise Plus edition

To disable query insights for Cloud SQL Enterprise Plus edition, do the following:

  1. In the Google Cloud console, go to the Cloud SQL Instances page.

    Go to Cloud SQL Instances

  2. To open the Overview page of an instance, click the instance name.
  3. Click Edit.
  4. In the Customize your instance section, expand Query insights.
  5. Clear the Enable Enterprise Plus features checkbox.
  6. Click Save.

What's next