Configuring database flags

MySQL | PostgreSQL | SQL Server

This page describes how to configure database flags for Cloud SQL, and lists the flags that you can set for your instance. You use database flags for many operations, including adjusting MySQL parameters, adjusting options, and configuring and tuning an instance.

In some cases, setting one flag may require that you set another flag to fully enable the desired functionality. For example, to enable slow query logging, you must set both the slow_query_log flag to on and the log_output flag to FILE to make your logs available using the Google Cloud Console Logs Viewer.

When you set, remove, or modify a flag for a database instance, the database might be restarted. The flag value is then persisted for the instance until you remove it. If the instance is the source of a replica, and the instance is restarted, the replica is also restarted to align with the current configuration of the instance.

Configuring database flags

Setting a database flag

Console

In the Google Cloud Console, create a new Cloud Console project, or open an existing project by selecting the project name.
Important: You should be aware that some resource identifiers (such as project IDs) might be retained beyond the life of your project. For this reason, avoid storing sensitive information in resource identifiers.
...see naming guidelines
Open the instance and click Edit.
Scroll down to the Flags section.
To set a flag that has not been set on the instance before, click Add item, choose the flag from the drop-down menu, and set its value.
Click Save to save your changes.
Confirm your changes under Flags on the Overview page.

gcloud

Edit the instance:

gcloud sql instances patch [INSTANCE_NAME] --database-flags [FLAG1=VALUE1,FLAG2=VALUE2]

This command will overwrite all database flags previously set. To keep those and add new ones, include the values for all flags you want set on the instance; any flag not specifically included is set to its default value. For flags that do not take a value, specify the flag name followed by an equals sign ("=").

For example, to set the general_log, skip_show_database, and wait_timeout flags, you can use the following command:

gcloud sql instances patch [INSTANCE_NAME] --database-flags \
    general_log=on,skip_show_database=on,wait_timeout=200000

REST v1beta4

To set a flag for an existing database:

Before using any of the request data below, 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":
  {
    "databaseFlags":
    [
      {
        "name": "flag_name",
        "value": "flag_value"
      }
    ]
  }
}

To send your request, expand one of these options:

curl (Linux, macOS, or Cloud Shell)

Note: The command below assumes that you have used either gcloud init or gcloud auth login to authenticate gcloud with your user account. You can check the currently active account by executing gcloud auth list.

Save the request body in a file called request.json, and execute the following command:

curl -X PATCH \
-H "Authorization: Bearer "$(gcloud auth print-access-token) \
-H "Content-Type: application/json; charset=utf-8" \
-d @request.json \
https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id

PowerShell (Windows)

Save the request body in a file called request.json, and execute the following command:

$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
  -Method PATCH `
  -Headers $headers `
  -ContentType: "application/json; charset=utf-8" `
  -InFile request.json `
  -Uri "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id" | Select-Object -Expand Content

You should receive a JSON response similar to the following:

Response

{
  "kind": "sql#operation",
  "targetLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id",
  "status": "PENDING",
  "user": "user@example.com",
  "insertTime": "2020-01-21T22:43:37.981Z",
  "operationType": "UPDATE",
  "name": "operation-id",
  "targetId": "instance-id",
  "selfLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/operations/operation-id",
  "targetProject": "project-id"
}

For example, to set the general_log flag for an existing database use:

Before using any of the request data below, 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":
  {
    "databaseFlags":
    [
      {
        "name": "general_log",
        "value": "on"
      }
    ]
  }
}

To send your request, expand one of these options:

curl (Linux, macOS, or Cloud Shell)

Save the request body in a file called request.json, and execute the following command:

curl -X PATCH \
-H "Authorization: Bearer "$(gcloud auth print-access-token) \
-H "Content-Type: application/json; charset=utf-8" \
-d @request.json \
https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id

PowerShell (Windows)

Save the request body in a file called request.json, and execute the following command:

$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
  -Method PATCH `
  -Headers $headers `
  -ContentType: "application/json; charset=utf-8" `
  -InFile request.json `
  -Uri "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id" | Select-Object -Expand Content

You should receive a JSON response similar to the following:

Response

{
  "kind": "sql#operation",
  "targetLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id",
  "status": "PENDING",
  "user": "user@example.com",
  "insertTime": "2020-01-21T22:43:37.981Z",
  "operationType": "UPDATE",
  "name": "operation-id",
  "targetId": "instance-id",
  "selfLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/operations/operation-id",
  "targetProject": "project-id"
}

If there are existing flags configured for the database, modify the previous command to include them. The PATCH command overwrites the existing flags with the ones specified in the request.

Clearing all flags to their default value

Console

In the Google Cloud Console, create a new Cloud Console project, or open an existing project by selecting the project name.
Important: You should be aware that some resource identifiers (such as project IDs) might be retained beyond the life of your project. For this reason, avoid storing sensitive information in resource identifiers.
...see naming guidelines
Open the instance and click Edit.
Open the Database flags section.
Click the X next to all of the flags shown.
Click Save to save your changes.

gcloud

Clear all flags to their default values on an instance:

gcloud sql instances patch [INSTANCE_NAME] --clear-database-flags

You are prompted to confirm that the instance will be restarted.

REST v1beta4

To clear all flags for an existing instance:

Before using any of the request data below, 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":
  {
    "databaseFlags": []
  }
}

To send your request, expand one of these options:

curl (Linux, macOS, or Cloud Shell)

Save the request body in a file called request.json, and execute the following command:

curl -X PATCH \
-H "Authorization: Bearer "$(gcloud auth print-access-token) \
-H "Content-Type: application/json; charset=utf-8" \
-d @request.json \
https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id

PowerShell (Windows)

Save the request body in a file called request.json, and execute the following command:

$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
  -Method PATCH `
  -Headers $headers `
  -ContentType: "application/json; charset=utf-8" `
  -InFile request.json `
  -Uri "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id" | Select-Object -Expand Content

You should receive a JSON response similar to the following:

Response

{
  "kind": "sql#operation",
  "targetLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id",
  "status": "PENDING",
  "user": "user@example.com",
  "insertTime": "2020-01-21T22:43:37.981Z",
  "operationType": "UPDATE",
  "name": "operation-id",
  "targetId": "instance-id",
  "selfLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/operations/operation-id",
  "targetProject": "project-id"
}

Viewing current values of database flags

To view all current values of the MySQL system variables, log into your instance with the mysql client and enter the following statement:

 SHOW VARIABLES;

Note that you can change the value only for supported flags (as listed below).

Determining what database flags have been set for an instance

To see what flags have been set for a Cloud SQL instance:

Console

In the Google Cloud Console, create a new Cloud Console project, or open an existing project by selecting the project name.
Important: You should be aware that some resource identifiers (such as project IDs) might be retained beyond the life of your project. For this reason, avoid storing sensitive information in resource identifiers.
...see naming guidelines
Select the instance to open its Instance Overview page.
The database flags that have been set are listed under the Database flags section.

gcloud

Get the instance state:

gcloud sql instances describe [INSTANCE_NAME]

In the output, database flags are listed under the settings as the collection databaseFlags. For more information about the representation of the flags in the output, see Instances Resource Representation.

REST v1beta4

To list flags configured for an instance:

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

project-id: The project ID
instance-id: The instance ID

HTTP method and URL:

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

To send your request, expand one of these options:

curl (Linux, macOS, or Cloud Shell)

Execute the following command:

curl -X GET \
-H "Authorization: Bearer "$(gcloud auth print-access-token) \
https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id

PowerShell (Windows)

Execute the following command:

$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
  -Method GET `
  -Headers $headers `
  -Uri "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id" | Select-Object -Expand Content

You should receive a JSON response similar to the following:

Response

{
  "settings":
  {
    "authorizedGaeApplications": [],
    "tier": "machine-type",
    "kind": "sql#settings",
    "availabilityType": "REGIONAL",
    "pricingPlan": "PER_USE",
    "replicationType": "SYNCHRONOUS",
    "activationPolicy": "ALWAYS",
    "ipConfiguration":
    {
      "privateNetwork": "projects/project-id/global/networks/default",
      "authorizedNetworks": [],
      "ipv4Enabled": false
    },
    "locationPreference":
    {
      "zone": "zone",
      "kind": "sql#locationPreference"
    },
    "databaseFlags": [
      {
        "name": "general_log",
        "value": "on"
      }
    ],
    "dataDiskType": "PD_SSD",
    "maintenanceWindow":
    {
      "kind": "sql#maintenanceWindow",
      "hour": 0,
      "day": 0
    },
    "backupConfiguration":
    {
      "startTime": "03:00",
      "kind": "sql#backupConfiguration",
      "enabled": true,
      "binaryLogEnabled": true
    },
    "settingsVersion": "54",
    "storageAutoResizeLimit": "0",
    "storageAutoResize": true,
    "dataDiskSizeGb": "10"
  }
}

In the output, look for the databaseFlags field.

Supported flags

The flags supported in Cloud SQL are the most commonly requested flags for MySQL. Flags not mentioned below are not supported.

For a given flag, Cloud SQL might support a different range from the corresponding MySQL parameter or option.

The flags apply to all versions of MySQL supported by Cloud SQL except where noted.

A | B | C | D | E | F | G | I | L | M | N | O | P | Q | R | S | T | U | W

Cloud SQL Flag	Type Acceptable Values and Notes	Restart Required?
activate_all_roles_on_login	`boolean` `on` \| `off` default: `off` Note: The flag is supported in MySQL 8.0 for Cloud SQL.	No
auto_increment_increment	`integer` `1` ... `65535`	No
auto_increment_offset	`integer` `1` ... `65535`	No
binlog_cache_size	`integer` `4096` ... `9223372036854775807`	No
binlog_expire_log_seconds	`integer` `0` ... `4294967295` MySQL 8.0 only. Default is 2592000, which equals 30 days. See the Tips section for more information about this flag.	No
binlog_group_commit_sync_delay	0 ... 1000000 Supported in MySQL 5.7, 8.0 Default is 0.	No
binlog_group_commit_sync_no_delay_count	0 ... 1000000 Supported in MySQL 5.7, 8.0 Default is 0.	No
binlog_row_image	`enumeration` `full` (default), `minimal`, or `noblob`	No
binlog_stmt_cache_size	`4096` ... `9223372036854775807`	No
binlog_transaction_dependency_history_size	`integer` For information about how to use this flag and its acceptable values, see Configuring parallel replication.	No
binlog_transaction_dependency_tracking	`enumeration` For information about how to use this flag and its acceptable values, see Configuring parallel replication.	No
character_set_server	`string` utf8 or utf8mb4 (recommended)	Yes
default_password_lifetime	`integer` `0...65535` default: `0` Note: The flag is supported in MySQL 8.0 for Cloud SQL.	No
default_time_zone	`string` Specify values as time zone offsets, from `-12:59` to `+13:00`. Leading zeros required. For example, London is in the UTC time zone, which is +00:00 in the supported values for this flag. Named areas, such as 'Europe/London', are not supported by Cloud SQL. Note: Automatic adjustment to daylight saving time is not supported. You must update this flag manually, on the primary instance and on all read replicas, to account for it.	Yes
disconnect_on_expired_password	`boolean` `on` \| `off` default: `on` Note: The flag is supported in MySQL 8.0 for Cloud SQL.	Yes
eq_range_index_dive_limit	`integer` `0` ... `2147483647`	No
event_scheduler	`boolean` `on` \| `off` If you are using the Event Scheduler, configure your instance with an activation policy of ALWAYS to ensure that scheduled events run.	No
expire_log_days	`integer` `0` ... `99` Default is 0, which means no automatic removal. See the Tips section for more information about this flag.	No
explicit_defaults_for_timestamp	`boolean` `on` \| `off`	No
ft_max_word_len	`integer` `10` ... `252`	Yes
ft_min_word_len	`integer` `1` ... `16`	Yes
ft_query_expansion_limit	`integer` `0` ... `1000`	Yes
general_log	`boolean` `on` \| `off` See the Tips section for more information about general logs.	No
generated_random_password_length	`integer` `5-255` default: `20` Note: The flag is supported in MySQL 8.0 for Cloud SQL.	No
group_concat_max_len	`integer` `4` ... `17179869184`	No
init_connect	`string`	No
innodb_adaptive_hash_index	`boolean` `on` \| `off`	No
innodb_adaptive_hash_index_parts	`integer` `1` ... `512`	Yes
innodb_adaptive_max_sleep_delay	`integer` `0` ... `1000000`	No
innodb_autoinc_lock_mode	`integer` `0` ... `2`	Yes
innodb_buffer_pool_size	`integer` Setting this flag for MySQL 5.6 requires a restart. See the Tips section for more information about this flag.	No
innodb_change_buffer_max_size	`integer` `0` ... `50`	No
innodb_concurrency_tickets	`integer` `1` ... `4294967295`	No
innodb_file_per_table	`boolean` `on` \| `off` See the Tips section for more information about this flag.	No
innodb_fill_factor	`integer` `10` ... `100`	No
innodb_flush_log_at_trx_commit	`integer` `1, 2` Default: `1`. See the Tips section for more information about this flag.	No
innodb_ft_cache_size	`integer` `1600000` ... `80000000`	Yes
innodb_ft_enable_diag_print	`boolean` `on` \| `off`	No
innodb_ft_enable_stopword	`boolean` `on` \| `off`	No
innodb_ft_max_token_size	`integer` `10` ... `252` Supported only in MySQL 5.6 and later versions.	Yes
innodb_ft_min_token_size	`integer` `0` ... `16` Supported only in MySQL 5.6 and later versions.	Yes
innodb_ft_num_word_optimize	`integer` `1000` ... `10000`	No
innodb_ft_result_cache_limit	`integer` `1000000` ... `4294967295`	No
innodb_ft_server_stopword_table	`string` Supported only in MySQL 5.6 and later versions.	No
innodb_ft_sort_pll_degree	`integer` `1` ... `32`	Yes
innodb_ft_total_cache_size	`integer` `32000000` ... `1600000000`	Yes
innodb_ft_user_stopword_table	`string`	No
innodb_large_prefix	`boolean` `on` \| `off` Supported only in MySQL 5.6.	No
innodb_lock_wait_timeout	`integer` `1` ... `1073741824`	No
innodb_log_buffer_size	`integer` `262144` ... `4294967295`	Yes
innodb_log_file_size	`integer` MySQL 5.6: `1048576` ... `274877906944` MySQL 5.7: `4194304` ... `274877906944`	Yes
innodb_lru_scan_depth	`integer` `100` ... `9223372036854775807`	No
innodb_old_blocks_pct	`integer` `5` ... `95`	No
innodb_old_blocks_time	`integer` `0` ... `4294967295`	No
innodb_online_alter_log_max_size	`integer` `65536` ... `9223372036854775807`	No
innodb_optimize_fulltext_only	`boolean` `on` \| `off`	No
innodb_print_all_deadlocks	`boolean` `on` \| `off`	No
innodb_purge_threads	`1 ... 32` Supported in MySQL 5.6, 5.7, 8.0 Default is 1.	Yes
innodb_random_read_ahead	`boolean` `on` \| `off`	No
innodb_read_ahead_threshold	`integer` `0` ... `64`	No
innodb_read_io_threads	`integer` `1` ... `64`	Yes
innodb_replication_delay	`integer` `0` ... `4294967295`	No
innodb_rollback_on_timeout	`boolean` `on` \| `off`	Yes
innodb_rollback_segments	`integer` `1` ... `128`	No
innodb_sort_buffer_size	`integer` `65536` ... `67108864`	Yes
innodb_stats_auto_recalc	`boolean` `on` \| `off`	No
innodb_stats_method	`enumeration` `nulls_equal` \| `nulls_unequal` \| `nulls_ignored`	No
innodb_stats_on_metadata	`boolean` `on` \| `off`	No
innodb_stats_persistent	`boolean` `on` \| `off`	No
innodb_stats_persistent_sample_pages	`integer` `1` ... `9223372036854775807`	No
innodb_stats_sample_pages	`integer` `1` ... `9223372036854775807`	No
innodb_stats_transient_sample_pages	`integer` `1` ... `9223372036854775807`	No
innodb_status_output	`boolean` `on` \| `off`	No
innodb_status_output_locks	`boolean` `on` \| `off`	No
innodb_strict_mode	`boolean` `on` \| `off`	No
innodb_sync_array_size	`1 ... 1024` Supported in MySQL 5.6, 5.7, 8.0 Default is 1.	Yes
innodb_thread_concurrency	`integer` `0` ... `1000`	No
innodb_thread_sleep_delay	`integer` `0` ... `1000000`	No
innodb_write_io_threads	`integer` `1` ... `64`	Yes
interactive_timeout	`integer` `1` ... `31536000`	No
internal_tmp_mem_storage_engine	`enumeration` `MEMORY`, `TempTable` This flag is used for MySQL 8.0 only.	No
join_buffer_size	`integer` `128` ... `9223372036854775807`	No
local_infile	`boolean` `on` \| `off`	No
lock_wait_timeout	`integer` `1` ... `31536000`	No
log_bin_trust_function_creators	`boolean` `on` \| `off`	No
log_output	`set` `FILE` \| `TABLE` \| `NONE`	No
log_queries_not_using_indexes	`boolean` `on` \| `off`	No
log_throttle_queries_not_using_indexes	`integer` `0` ... `9223372036854775807`	No
long_query_time	`float` `0` ... `30000000` Cloud SQL provides the ability to set this flag to less than 1 if needed. If the `log_queries_not_using_indexes` flag is also enabled, you may see queries with less than the time specified here.	No
lower_case_table_names	`integer` `0` or `1` In most cases, use the default value of 0, which makes table and database names case sensitive. If you need to change the value of this flag, make sure that you understand how the change will affect your existing tables and databases. Warning: This flag is not supported for MySQL 8.0 for Cloud SQL.	Yes
mandatory_roles	`string` `role name` default: `empty string` Note: The flag is supported in MySQL 8.0 for Cloud SQL.	No
max_allowed_packet	`integer` `16384` ... `1073741824` This value must be a multiple of 1024, if sql_mode=TRADITIONAL or sql_mode=STRICT_ALL_TABLES.	No
max_binlog_size	`integer` `4096` ... `1073741824`	No
max_connections	`integer` `14` ... `262143`	Yes
max_digest_length	`integer` `0` ... `1048576`	Yes
max_execution_time	`integer` `0` ... `9223372036854775807`	No
max_heap_table_size	`integer` `16384` ... `67108864` See the Tips section for more information about this flag.	No
max_join_size	`integer` `16` ... `9223372036854775807`	No
max_length_for_sort_data	`integer` `4` ... `8388608`	No
max_points_in_geometry	`integer` `3` ... `1048576`	No
max_prepared_stmt_count	`integer` `0` ... `1048576`	No
max_seeks_for_key	`integer` `1` ... `9223372036854775807`	No
max_sort_length	`integer` `4` ... `8388608`	No
max_sp_recursion_depth	`integer` `0` ... `255`	No
max_user_connections	`integer` `0` ... `4294967295`	No
max_write_lock_count	`integer` `1` ... `9223372036854775807`	No
net_read_timeout	`integer` `30` ... `4294967295`	No
net_retry_count	`integer` `10` ... `4294967295`	No
net_write_timeout	`integer` `60` ... `4294967295`	No
optimizer_prune_level	`integer` `0` ... `1`	No
optimizer_search_depth	`integer` `0` ... `62`	No
optimizer_trace_max_mem_size	`integer` `0` ... `9223372036854775807`	No
optimizer_trace_offset	`integer` `-9223372036854775808` ... `9223372036854775807`	No
parser_max_mem_size	`integer` `10000000` ... `9223372036854775807`	No
password_history	`integer` `0-4294967295` default: `0` Note: The flag is supported in MySQL 8.0 for Cloud SQL.	No
password_require_current	`boolean` `on` \| `off` default: `off` Note: The flag is supported in MySQL 8.0 for Cloud SQL.	No
password_reuse_interval	`integer` `0-4294967295` default: `0` Note: The flag is supported in MySQL 8.0 for Cloud SQL.	No
performance_schema	`boolean` `on` \| `off` (default) See Tips section for more information about performance_schema flags.	Yes
performance_schema_accounts_size	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_digests_size	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_events_stages_history_long_size	`integer` `-1` ... `1048576`	Yes
performance_schema_events_stages_history_size	`integer` `-1` ... `1024` See Tips section for more information about performance_schema flags.	Yes
performance_schema_events_statements_history_long_size	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_events_statements_history_size	`integer` `-1` ... `1024` See Tips section for more information about performance_schema flags.	Yes
performance_schema_events_transactions_history_long_size	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_events_transactions_history_size	`integer` `-1` ... `1024` See Tips section for more information about performance_schema flags.	Yes
performance_schema_events_waits_history_long_size	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_events_waits_history_size	`integer` `-1` ... `1024` See Tips section for more information about performance_schema flags.	Yes
performance_schema_hosts_size	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_cond_classes	`integer` `0` ... `256` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_cond_instances	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_digest_length	`integer` `0` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_file_classes	`integer` `0` ... `256` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_file_handles	`integer` `0` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_file_instances	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_index_stat	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_memory_classes	`integer` `0` ... `1024` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_metadata_locks	`integer` `-1` ... `104857600` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_mutex_classes	`integer` `0` ... `256` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_mutex_instances	`integer` `-1` ... `104857600` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_prepared_statements_instances	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_program_instances	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_rwlock_classes	`integer` `0` ... `256` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_rwlock_instances	`integer` `-1` ... `104857600` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_socket_classes	`integer` `0` ... `256` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_socket_instances	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_sql_text_length	`integer` `0` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_stage_classes	`integer` `0` ... `256` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_statement_classes	`integer` `0` ... `256` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_statement_stack	`integer` `1` ... `256` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_table_handles	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_table_instances	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_table_lock_stat	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_thread_classes	`integer` `0` ... `256` See Tips section for more information about performance_schema flags.	Yes
performance_schema_max_thread_instances	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_session_connect_attrs_size	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_setup_actors_size	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_setup_objects_size	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
performance_schema_users_size	`integer` `-1` ... `1048576` See Tips section for more information about performance_schema flags.	Yes
query_alloc_block_size	`integer` `1024` ... `4294967295`	No
query_cache_limit	`integer` `0` ... `223338299392` This flag is not available for MySQL 8.0 as the query cache is deprecated as of MySQL 5.7.20, and is removed in MySQL 8.0.	No
query_cache_min_res_unit	`integer` `0` ... `9223372036854775807` This flag is not available for MySQL 8.0 as the query cache is deprecated as of MySQL 5.7.20, and is removed in MySQL 8.0.	No
query_cache_size	`integer` `0` ... `223338299392` This flag is not available for MySQL 8.0 as the query cache is deprecated as of MySQL 5.7.20, and is removed in MySQL 8.0. See the Tips section for more information about this flag.	No
query_cache_type	`enumeration` `0` ... `2` This flag is not available for MySQL 8.0 as the query cache is deprecated as of MySQL 5.7.20, and is removed in MySQL 8.0. See the Tips section for more information about this flag.	Yes
query_cache_wlock_invalidate	`boolean` `on` \| `off` This flag is not available for MySQL 8.0 as the query cache is deprecated as of MySQL 5.7.20, and is removed in MySQL 8.0.	No
query_prealloc_size	`integer` `8192` ... `9223372036854775807`	No
range_alloc_block_size	`integer` `4096` ... `4294967295`	No
range_optimizer_max_mem_size	`integer` `0` ... `9223372036854775807`	No
read_buffer_size	`integer` `8192` ... `2147483647`	No
read_only	`boolean` `on` \| `off` Has no effect for replicas.	No
read_rnd_buffer_size	`integer` `1` ... `2147483647`	No
show_compatibility_56	`boolean` `on` \| `off` Supported only in MySQL 5.7.	No
skip_show_database	`flag` `on` \| `off`	Yes
slave_parallel_type	`enumeration` For information about how to use this flag and its acceptable values, see Configuring parallel replication.	No
slave_parallel_workers	`integer` For information about how to use this flag and its acceptable values, see Configuring parallel replication.	No
slave_preserve_commit_order	`boolean` For information about how to use this flag and its acceptable values, see Configuring parallel replication.	No
slave_pending_jobs_size_max	`integer` For information about how to use this flag and its acceptable values, see Configuring parallel replication.	No
slow_query_log	`boolean` `on` \| `off` See the Tips section for more information on slow query logs.	No
sort_buffer_size	`integer` `32768` ... `9223372036854775807`	No
sql_mode	`string` See the Server SQL Modes in the MySQL documentation for allowed values, including combined modes, such as `ANSI`. `NO_DIR_IN_CREATE` is not supported. Cloud SQL for MySQL doesn't support empty values for the `sql_mode` flag. Instead of using an empty value, set this flag to the `NO_ENGINE_SUBSTITUTION` mode. If specifying a comma-separated list of modes using gcloud commands, use the --flags-file argument.	No
stored_program_cache	`integer` `16` ... `524288`	No
sync_binlog	`integer` `0` ... `4294967295` Supported only on read replicas and external server replicas in MySQL 5.7 and 8.0. The default setting of 1 enables the synchronization of the binary log to disk before transactions are committed. This flag is not supported on primary instances or legacy HA failover replicas. If a replica using this flag is promoted, the flag is removed.	No
table_definition_cache	`integer` `400` ... `524288`	No
table_open_cache	`integer` `1` ... `524288`	No
table_open_cache_instances	`integer` `1` ... `64`	Yes
thread_cache_size	`integer` `0` ... `16384`	No
thread_stack	`integer` `131072` ... `9223372036854775807`	Yes
tmp_table_size	`integer` `1024` ... `67108864` See the Tips section for more information about this flag.	No
transaction_alloc_block_size	`integer` `1024` ... `131072`	No
transaction_isolation	`enumeration` `READ-UNCOMMITTED` \| `READ-COMMITTED` \| `REPEATABLE-READ` \| `SERIALIZABLE`	Yes
transaction_prealloc_size	`integer` `1024` ... `131072`	No
transaction_write_set_extraction	`enumeration` For information about how to use this flag and its acceptable values, see Configuring parallel replication.	No
updatable_views_with_limit	`integer` `0` ... `1`	No
wait_timeout	`integer` `1` ... `31536000`	No

Tips for working with flags

general_log, slow_query_log

To make your general or slow query logs available, enable the corresponding flag and set the log_output flag to FILE. This makes the log output available using the Logs Viewer in the Google Cloud Console. Note that Google Cloud's operations suite logging charges apply. To minimize instance storage cost, general and slow query logs on the instance disk will be rotated when the log file is older than 24 hours (and no changes have been made within that duration) or greater than 100MB in size. Old log files will be automatically deleted after the rotation.

If log_output is set to NONE, you will be unable to access the logs. If you set log_output to TABLE, the log output is placed in a table in your database. If this table becomes large, it can affect instance restart time or cause the instance to lose its SLA coverage; for this reason, the TABLE option is not recommended. If needed, you can truncate your log tables by using the API. For more information, see the instances.truncateLog reference page.

MySQL provides a more sophisticated utility for examining and procesing binary log files called mysqlbinlog. This utility is available with the MySQL Server software. If you have a MySQL instance, then you can use mysqlbinlog to determine your desired recovery position.

expire_logs_days, binlog_expire_logs_seconds: If you enable point-in-time recovery, the expiration period of your binary logs will be determined by the lesser of your transaction log retention period and the value of this flag. For more information, see the transaction log retention page.

innodb_buffer_pool_size

The value of the innodb_buffer_pool_size is the size in bytes of the buffer pool. You cannot enable this flag on instances that have fewer than 3,840 MiB of RAM.

This flag is not configurable for shared-core machine types (f1_micro and g1_small). Changing this flag on MySQL 5.6 requires a restart.

In Cloud SQL, the default, minimum allowable, and maximum allowable values of the innodb_buffer_pool_size flag depend on the instance's memory. These values can be roughly calculated as a percentage of the instance's RAM. By default, the value of this flag is typically set close to the maximum allowable value. The maximum allowable allocation percentage increases with instance size. The minimum allowable value is usually about 20% of the instance's RAM.

Approximate values for this flag:

Instance RAM Range	Min %	Default %	Max %
0 - 4.0GB of RAM		~34%
4.0GB - 7.5GB	~20%	~34%	~34%
7.5GB - 12GB	~20%	~52%	~52%
12GB - 24GB	~20%	~67%	~67%
24GB and above	~20%	~72%	~72%

Your exact values may vary. To calculate the current value for your instance, you can run the query:

  show global variables like 'innodb_buffer_pool_size'

For reference, the minimum allowable, default, and maximum allowable values are provided for the predefined machine types below.

Predefined machine type	Instance RAM (GB)	Min (GB) (% of total)	Default (GB) (% of total)	Max (GB) (% of total)
f1-micro	0.6	-	0.053	-
g1-small	1.7	-	0.625	-
db-custom-1-3840	3.75	0.875 (23%)	1.375 (37%)	1.375 (37%)
db-custom-2-7680	7.5	1.5 (20%)	4 (53%)	4 (53%)
db-custom-4-15360	15	3 (20%)	10.5 (70%)	10.5 (70%)
db-custom-8-30720	30	6 (20%)	22 (73%)	22 (73%)
db-custom-16-61440	60	12 (20%)	44 (73%)	44 (73%)
db-custom-32-122880	120	24 (20%)	87 (73%)	87 (73%)
db-custom-64-245760	240	48 (20%)	173 (72%)	173 (72%)
db-custom-96-368640	360	72 (20%)	260 (72%)	260 (72%)
db-custom-2-13312	13	3 (23%)	9 (69%)	9 (69%)
db-custom-4-26624	26	6 (23%)	19 (73%)	19 (73%)
db-custom-8-53248	52	11 (21%)	38 (73%)	38 (73%)
db-custom-16-106496	104	21 (20%)	75 (72%)	75 (72%)
db-custom-32-212992	208	42 (20%)	150 (72%)	150 (72%)
db-custom-64-425984	416	84 (20%)	300 (72%)	300 (72%)
db-custom-96-638976	624	125 (20%)	450 (72%)	450 (72%)

innodb_file_per_table

For all MySQL versions 5.6 and higher, the default value is ON.

innodb_flush_log_at_trx_commit

If you need higher performance, we recommend setting the value to 2. Cloud SQL does not support setting the value for this flag to 0. If you set the flag value to 2, you must either disable the binary log on the replica, or set sync_binlog to a value other than 1.

You can only enable this flag for read replicas and external server replicas. For external server replicas, this flag must be set to the default value of 1 for full ACID compliance. You cannot enable this flag on primary instances or failover replicas.

max_heap_table_size, tmp_table_size

Exhausting the available instance memory can occur when you set tmp_table_size and max_heap_table_size too high for the number of concurrent queries the instance processes. Exhausting the memory will result in an instance crash and restart.

For more information about working with these flags, see How MySQL Uses Internal Temporary Tables and The MEMORY Storage Engine.

performance_schema

You cannot enable this flag on instances that have fewer than 26,624 MiB of RAM. If you enable this flag, you cannot change your machine type to a size that does not support the flag; you must first disable this flag.

Flags managed by Cloud SQL

Cloud SQL adjusts certain system flags depending on the instance machine type. You cannot adjust these values.

innodb_buffer_pool_instances

1 for db-f1-micro and db-g1-small.
1 if RAM < 7.5 GB.
2 if 7.5 GB <= RAM < 13 GB.
4 if 13 GB <= RAM < 26 GB.
8 if RAM >= 26 GB.

Troubleshooting

Click the links in the table for details:

For this problem...	The issue might be...	Try this...
Enabling a flag crashes the instance.	The `max_connections` flag value may be set too high.	Contact customer support to request a flag removal.
Time zone doesn't automatically change.	Automated time zone change is not supported.	Time must be changed manually. Learn more.
`Bad syntax for dict arg`.	Complex parameter values require special treatment.	Learn more.

Enabling a flag crashes the instance

After enabling a flag the instances loop between panicking and crashing.

The issue might be

Setting the max_connections flag value too high causes this error.

Things to try

Contact customer support to request a flag removal followed by a hard drain. This forces the instance to restart on a different host with a fresh configuration without the undesired flag or setting.

Time zone doesn't automatically change

The time zone didn't automatically change for daylight savings time.

The issue might be

Automated time zone changes are not supported in Cloud SQL and must be done manually, and not by string but by time zone offset value.

Things to try

Edit the instance to change the default_time_zone flag. Named areas are not supported. For example: Europe/LondonLondon is in the UTC time zone, which would be a supported value of +00:00 for the default_time_zone flag.

Bad syntax for dict arg

You see the error message Bad syntax for dict arg when trying to set a flag.

The issue might be

Complex parameter values, such as comma-separated lists, require special treatment when used with gcloud commands.

Things to try

Use the gcloud --flags-file parameter, which specifies a YAML or JSON file containing a --flag:value dictionary useful for complex flag values.

What's next

Learn more about MySQL system variables.
Learn more about Operational Guidelines.