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MySQL | PostgreSQL | SQL Server
This page describes how to manage instances with a high number of open tables
and a high number of open table definitions. This recommender is called Manage open tables.
Every day, this recommender analyzes metrics for the following:
The number of open tables or open table definitions for an instance as follows:
If the number of open tables or open table definitions increases by 1 table
every 2 seconds, or faster, during the previous 24 hours.
If the number of open tables or open table definitions is equal to or more
than the value of table_open_cache and table_definition_cache,
respectively.
If either of these are true, then the recommender advises you to increase the
value of table_open_cache or table_definition_cache.
For more information on increasing the value of table_open_cache and
table_definition_cache, see Table limit.
GET https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/recommenders/google.cloudsql.instance.PerformanceRecommender/recommendations
Replace the following:
PROJECT_ID: your project ID
LOCATION: a region where your instances are located, such as us-central1
View insights and detailed recommendations
To view insights and detailed recommendations, follow these steps:
Console
Do one of the following:
On the Performance Recommendations page, click the Performance
recommendations card and then click Manage open tables. The
recommendation panel appears, which contains insights and detailed
recommendations for the instance.
On the Instances page, click Manage open tables.
The list of instances displays only those instances for which the
recommendation applies.
GET https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/insightTypes/google.cloudsql.instance.PerformanceInsight/insights
Replace the following:
PROJECT_ID: your project ID
LOCATION: a region where your instances are located, such as us-central1
Apply the recommendation
To implement this recommendation, do one of the following:
For a high number of open tables, increase the value of table_open_cache by
500 until the recommendation disappears.
For a high number of open table definitions, increase the value of
table_definition_cache by 500 until the recommendation disappears.
This recommendation is updated daily, so after you increase the value of either
table_open_cache or table_definition_cache, wait for 24 hours before
checking the recommendation again. For more information on increasing the value
of table_open_cache and table_definition_cache, see Table limit.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-22 UTC."],[],[],null,["# Manage open tables and open table definitions\n\n\u003cbr /\u003e\n\nMySQL \\| PostgreSQL \\| SQL Server\n\n\u003cbr /\u003e\n\n|\n| **Preview\n| --- [Gemini in Databases](/gemini/docs/overview)**\n|\n|\n| This feature is subject to the \"Pre-GA Offerings Terms\" in the General Service Terms section\n| of the [Service Specific Terms](/terms/service-terms#1).\n|\n| You can process personal data for this feature as outlined in the\n| [Cloud Data Processing\n| Addendum](/terms/data-processing-addendum), subject to the obligations and restrictions described in the agreement under\n| which you access Google Cloud.\n|\n| Pre-GA features are available \"as is\" and might have limited support.\n|\n| For more information, see the\n| [launch stage descriptions](/products#product-launch-stages).\n\nThis page describes how to manage instances with a high number of open tables\nand a high number of open table definitions. This [recommender](/recommender/docs/recommenders) is called **Manage open tables**.\n\nEvery day, this recommender analyzes metrics for the following:\n\n- The number of open tables or open table definitions for an instance as follows:\n - If the number of open tables or open table definitions increases by 1 table every 2 seconds, or faster, during the previous 24 hours.\n - If the number of open tables or open table definitions is equal to or more than the value of `table_open_cache` and `table_definition_cache`, respectively. If either of these are true, then the recommender advises you to increase the value of `table_open_cache` or `table_definition_cache`.\n\nFor more information on increasing the value of `table_open_cache` and\n`table_definition_cache`, see [Table limit](/sql/docs/quotas#table_limit).\n\nPricing\n-------\n\nThe **Manage open tables** recommender is in the *Standard*\n[Recommender pricing tier](/recommender/pricing).\n\nBefore you begin\n----------------\n\n[Enable the Recommender API](/recommender/docs/enabling).\n\n### Required roles and permissions\n\nTo get the permissions to view and work with insights and recommendations,\nensure that you have the required [Identity and Access Management (IAM) roles](/sql/docs/mysql/project-access-control#roles).\n\nFor more information about IAM roles, see [IAM basic and predefined roles reference](/iam/docs/understanding-roles) and [Manage access to projects, folders, and organizations](/iam/docs/granting-changing-revoking-access).\n\n\u003cbr /\u003e\n\nList the recommendations\n------------------------\n\nTo list the recommendations, follow these steps: \n\n### Console\n\nTo list recommendations about instance performance, follow these steps:\n\n1. Go to the **Cloud SQL Instances** page.\n\n[Go to Cloud SQL Instances](https://console.cloud.google.com/sql/instances)\n\n1. On the **Improve instance health by investigating issues and acting on\n recommendations** banner, click **Expand Details** .\n\nAlternatively, follow these steps:\n\n1. Go to the **Recommendation Hub** . See also [Find and apply recommendations with the Recommendations](/recommender/docs/recommendation-hub/identify-configuration-problems).\n\n [Go to the Recommendation Hub](https://console.cloud.google.com/home/recommendations/)\n2. In the **All recommendations** card, click **Performance** .\n\n### gcloud\n\nRun the [`gcloud recommender recommendations list`](/sdk/gcloud/reference/recommender/recommendations/list) command as follows: \n\n```\ngcloud recommender recommendations list \\\n--project=PROJECT_ID \\\n--location=LOCATION \\\n--recommender=google.cloudsql.instance.PerformanceRecommender \\\n--filter=recommenderSubtype=MYSQL_RECONFIG_OPEN_TABLES\n```\n\nReplace the following:\n\n- \u003cvar translate=\"no\"\u003ePROJECT_ID\u003c/var\u003e: your project ID\n- \u003cvar translate=\"no\"\u003eLOCATION\u003c/var\u003e: a region where your instances are located, such as `us-central1`\n\n### API\n\nCall the [`recommendations.list`](/recommender/docs/reference/rest/v1/projects.locations.recommenders.recommendations/list) method as follows: \n\n```\nGET https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/recommenders/google.cloudsql.instance.PerformanceRecommender/recommendations\n```\n\nReplace the following:\n\n- \u003cvar translate=\"no\"\u003ePROJECT_ID\u003c/var\u003e: your project ID\n- \u003cvar translate=\"no\"\u003eLOCATION\u003c/var\u003e: a region where your instances are located, such as `us-central1`\n\nView insights and detailed recommendations\n------------------------------------------\n\nTo view insights and detailed recommendations, follow these steps: \n\n### Console\n\nDo one of the following:\n\n- On the **Performance Recommendations** page, click the **Performance\n recommendations** card and then click **Manage open tables**. The\n recommendation panel appears, which contains insights and detailed\n recommendations for the instance.\n\n- On the **Instances** page, click **Manage open tables**.\n The list of instances displays only those instances for which the\n recommendation applies.\n\n### gcloud\n\nRun the [`gcloud recommender insights list`](/sdk/gcloud/reference/recommender/insights/list) command as follows: \n\n```\n\ngcloud recommender insights list \\\n--project=PROJECT_ID \\\n--location=LOCATION \\\n--insight-type=google.cloudsql.instance.PerformanceInsight \\\n--filter=insightSubtype=INSIGHT_SUBTYPE\n\n```\n\nReplace the following:\n\n- \u003cvar translate=\"no\"\u003ePROJECT_ID\u003c/var\u003e: your project ID\n- \u003cvar translate=\"no\"\u003eLOCATION\u003c/var\u003e: a region where your instances are located, such as `us-central1`\n- \u003cvar translate=\"no\"\u003eINSIGHT_SUBTYPE\u003c/var\u003e: set this parameter to one of the following:\n - `MYSQL_HIGH_NUMBER_OF_OPEN_TABLES`: display insights for the number of open tables for your instance\n - `MYSQL_HIGH_NUMBER_OF_OPEN_TABLE_DEFINITIONS`: display insights for the number of open table definitions for your instance\n\n### API\n\nCall the [`insights.list`](/recommender/docs/reference/rest/v1/projects.locations.insightTypes.insights/list) method as follows: \n\n```\n\nGET https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/insightTypes/google.cloudsql.instance.PerformanceInsight/insights\n\n```\n\nReplace the following:\n\n- \u003cvar translate=\"no\"\u003ePROJECT_ID\u003c/var\u003e: your project ID\n- \u003cvar translate=\"no\"\u003eLOCATION\u003c/var\u003e: a region where your instances are located, such as `us-central1`\n\nApply the recommendation\n------------------------\n\nTo implement this recommendation, do one of the following:\n\n- For a high number of open tables, increase the value of `table_open_cache` by\n 500 until the recommendation disappears.\n\n- For a high number of open table definitions, increase the value of\n `table_definition_cache` by 500 until the recommendation disappears.\n\n| **Note:** Increasing `table_open_cache` or`table_definition_cache` requires more memory. After increasing these flags, monitor the memory usage .\n\nThis recommendation is updated daily, so after you increase the value of either\n`table_open_cache` or `table_definition_cache`, wait for 24 hours before\nchecking the recommendation again. For more information on increasing the value\nof `table_open_cache` and `table_definition_cache`, see [Table limit](/sql/docs/quotas#table_limit).\n\nWhat's next\n-----------\n\n- [Google Cloud recommenders](/recommender/docs/recommenders)"]]
