The Vitess Docs | vttablet

vttablet

A VTTablet server controls a running MySQL server. VTTablet supports two primary types of deployments:

Managed MySQL (most common)
External MySQL

In addition to these deployment types, a partially managed VTTablet is also possible by setting --disable_active_reparents.

Example Usage #

Managed MySQL #

In this mode, Vitess actively manages MySQL:

export TOPOLOGY_FLAGS="--topo_implementation etcd2 --topo_global_server_address localhost:2379 --topo_global_root /vitess/global"
export VTDATAROOT="/tmp"

vttablet \
$TOPOLOGY_FLAGS
--tablet-path $alias
--init_keyspace $keyspace
--init_shard $shard
--init_tablet_type $tablet_type
--port $port
--grpc_port $grpc_port
--service_map 'grpc-queryservice,grpc-tabletmanager,grpc-updatestream'

$alias needs to be of the form: <cell>-id, and the cell should match one of the local cells that was created in the topology. The id can be left padded with zeroes: cell-100 and cell-000000100 are synonymous.

External MySQL #

In this mode, an external MySQL can be used such as AWS RDS, AWS Aurora, Google CloudSQL; or just an existing (vanilla) MySQL installation.

See Unmanaged Tablet for the full guide.

Even if a MySQL is external, you can still make vttablet perform some management functions. They are as follows:

--disable_active_reparents: If this flag is set, then any reparent or replica commands will not be allowed. These are InitShardPrimary, PlannedReparentShard, EmergencyReparentShard, and ReparentTablet. In this mode, you should use the TabletExternallyReparented command to inform vitess of the current primary.
--replication_connect_retry: This value is give to mysql when it connects a replica to the primary as the retry duration parameter.
--heartbeat_enable and --heartbeat_interval duration: cause vttablet to write heartbeats to the sidecar database. This information is also used by the replication reporter to assess replica lag.

Options #

The following global options apply to vttablet:

Name	Type	Definition
--alsologtostderr	boolean	log to standard error as well as files
--app_idle_timeout	duration	Idle timeout for app connections (default 1m0s)
--app_pool_size	int	Size of the connection pool for app connections (default 40)
--azblob_backup_account_key_file	string	Path to a file containing the Azure Storage account key; if this flag is unset, the environment variable VT_AZBLOB_ACCOUNT_KEY will be used as the key itself (NOT a file path).
--azblob_backup_account_name	string	Azure Storage Account name for backups; if this flag is unset, the environment variable VT_AZBLOB_ACCOUNT_NAME will be used.
--azblob_backup_buffer_size	int	The memory buffer size to use in bytes, per file or stripe, when streaming to Azure Blob Service. (default 104857600)
--azblob_backup_container_name	string	Azure Blob Container Name.
--azblob_backup_parallelism	int	Azure Blob operation parallelism (requires extra memory when increased -- a multiple of azblob_backup_buffer_size). (default 1)
--azblob_backup_storage_root	string	Root prefix for all backup-related Azure Blobs; this should exclude both initial and trailing '/' (e.g. just 'a/b' not '/a/b/').
--backup_engine_implementation	string	Specifies which implementation to use for creating new backups (builtin or xtrabackup). Restores will always be done with whichever engine created a given backup. (default "builtin")
--backup_storage_block_size	int	if backup_storage_compress is true, backup_storage_block_size sets the byte size for each block while compressing (default is 250000). (default 250000)
--backup_storage_compress	boolean	if set, the backup files will be compressed. (default true)
--backup_storage_implementation	string	Which backup storage implementation to use for creating and restoring backups.
--backup_storage_number_blocks	int	if backup_storage_compress is true, backup_storage_number_blocks sets the number of blocks that can be processed, at once, before the writer blocks, during compression (default is 2). It should be equal to the number of CPUs available for compression. (default 2)
--binlog_host	string	PITR restore parameter: hostname/IP of binlog server.
--binlog_password	string	PITR restore parameter: password of binlog server.
--binlog_player_grpc_ca	string	the server ca to use to validate servers when connecting
--binlog_player_grpc_cert	string	the cert to use to connect
--binlog_player_grpc_crl	string	the server crl to use to validate server certificates when connecting
--binlog_player_grpc_key	string	the key to use to connect
--binlog_player_grpc_server_name	string	the server name to use to validate server certificate
--binlog_player_protocol	string	the protocol to download binlogs from a vttablet (default "grpc")
--binlog_port	int	PITR restore parameter: port of binlog server.
--binlog_ssl_ca	string	PITR restore parameter: Filename containing TLS CA certificate to verify binlog server TLS certificate against.
--binlog_ssl_cert	string	PITR restore parameter: Filename containing mTLS client certificate to present to binlog server as authentication.
--binlog_ssl_key	string	PITR restore parameter: Filename containing mTLS client private key for use in binlog server authentication.
--binlog_ssl_server_name	string	PITR restore parameter: TLS server name (common name) to verify against for the binlog server we are connecting to (If not set: use the hostname or IP supplied in --binlog_host).
--binlog_user	string	PITR restore parameter: username of binlog server.
--builtinbackup-file-read-buffer-size	uint	read files using an IO buffer of this many bytes. Golang defaults are used when set to 0.
--builtinbackup-file-write-buffer-size	uint	write files using an IO buffer of this many bytes. Golang defaults are used when set to 0. (default 2097152)
--builtinbackup_mysqld_timeout	duration	how long to wait for mysqld to shutdown at the start of the backup. (default 10m0s)
--builtinbackup_progress	duration	how often to send progress updates when backing up large files. (default 5s)
--catch-	sigpipe	catch and ignore SIGPIPE on stdout and stderr if specified
--ceph_backup_storage_config	string	Path to JSON config file for ceph backup storage. (default "ceph_backup_config.json")
--compression-engine-name	string	compressor engine used for compression. (default "pargzip")
--compression-level	int	what level to pass to the compressor. (default 1)
--consolidator-stream-query-size	int	Configure the stream consolidator query size in bytes. Setting to 0 disables the stream consolidator. (default 2097152)
--consolidator-stream-total-size	int	Configure the stream consolidator total size in bytes. Setting to 0 disables the stream consolidator. (default 134217728)
--consul_auth_static_file	string	JSON File to read the topos/tokens from.
--datadog-agent-host	string	host to send spans to. if empty, no tracing will be done
--datadog-agent-port	string	port to send spans to. if empty, no tracing will be done
--db-credentials-file	string	db credentials file; send SIGHUP to reload this file
--db-credentials-server	string	db credentials server type ('file' - file implementation; 'vault' - HashiCorp Vault implementation) (default "file")
--db-credentials-vault-addr	string	URL to Vault server
--db-credentials-vault-path	string	Vault path to credentials JSON blob, e.g.: secret/data/prod/dbcreds
--db-credentials-vault-role-mountpoint	string	Vault AppRole mountpoint; can also be passed using VAULT_MOUNTPOINT environment variable (default "approle")
--db-credentials-vault-role-secretidfile	string	Path to file containing Vault AppRole secret_id; can also be passed using VAULT_SECRETID environment variable
--db-credentials-vault-roleid	string	Vault AppRole id; can also be passed using VAULT_ROLEID environment variable
--db-credentials-vault-timeout	duration	Timeout for vault API operations (default 10s)
--db-credentials-vault-tls-ca	string	Path to CA PEM for validating Vault server certificate
--db-credentials-vault-tokenfile	string	Path to file containing Vault auth token; token can also be passed using VAULT_TOKEN environment variable
--db-credentials-vault-ttl	duration	How long to cache DB credentials from the Vault server (default 30m0s)
--db_allprivs_password	string	db allprivs password
--db_allprivs_use_ssl	boolean	Set this flag to false to make the allprivs connection to not use ssl (default true)
--db_allprivs_user	string	db allprivs user userKey (default "vt_allprivs")
--db_app_password	string	db app password
--db_app_use_ssl	boolean	Set this flag to false to make the app connection to not use ssl (default true)
--db_app_user	string	db app user userKey (default "vt_app")
--db_appdebug_password	string	db appdebug password
--db_appdebug_use_ssl	boolean	Set this flag to false to make the appdebug connection to not use ssl (default true)
--db_appdebug_user	string	db appdebug user userKey (default "vt_appdebug")
--db_charset	string	Character set used for this tablet. (default "utf8mb4")
--db_conn_query_info	boolean	enable parsing and processing of QUERY_OK info fields
--db_connect_timeout_ms	int	connection timeout to mysqld in milliseconds (0 for no timeout)
--db_dba_password	string	db dba password
--db_dba_use_ssl	boolean	Set this flag to false to make the dba connection to not use ssl (default true)
--db_dba_user	string	db dba user userKey (default "vt_dba")
--db_erepl_password	string	db erepl password
--db_erepl_use_ssl	boolean	Set this flag to false to make the erepl connection to not use ssl (default true)
--db_erepl_user	string	db erepl user userKey (default "vt_erepl")
--db_filtered_password	string	db filtered password
--db_filtered_use_ssl	boolean	Set this flag to false to make the filtered connection to not use ssl (default true)
--db_filtered_user	string	db filtered user userKey (default "vt_filtered")
--db_flags	uint	Flag values as defined by MySQL.
--db_flavor	string	Flavor overrid. Valid value is FilePos.
--db_host	string	The host name for the tcp connection.
--db_port	int	tcp port
--db_repl_password	string	db repl password
--db_repl_use_ssl	boolean	Set this flag to false to make the repl connection to not use ssl (default true)
--db_repl_user	string	db repl user userKey (default "vt_repl")
--db_server_name	string	server name of the DB we are connecting to.
--db_socket	string	The unix socket to connect on. If this is specified, host and port will not be used.
--db_ssl_ca	string	connection ssl ca
--db_ssl_ca_path	string	connection ssl ca path
--db_ssl_cert	string	connection ssl certificate
--db_ssl_key	string	connection ssl key
--db_ssl_mode	SslMode	SSL mode to connect with. One of disabled, preferred, required, verify_ca & verify_identity.
--db_tls_min_version	string	Configures the minimal TLS version negotiated when SSL is enabled. Defaults to TLSv1.2. Options: TLSv1.0, TLSv1.1, TLSv1.2, TLSv1.3.
--dba_idle_timeout	duration	Idle timeout for dba connections (default 1m0s)
--dba_pool_size	int	Size of the connection pool for dba connections (default 20)
--degraded_threshold	duration	replication lag after which a replica is considered degraded (default 30s)
--disable-replication-manager	boolean	Disable replication manager to prevent replication repairs.
--disable_active_reparents	boolean	if set, do not allow active reparents. Use this to protect a cluster using external reparents.
--emit_stats	boolean	If set, emit stats to push-based monitoring and stats backends
--enable-consolidator	boolean	Synonym to -enable_consolidator (default true)
--enable-consolidator-replicas	boolean	Synonym to -enable_consolidator_replicas
--enable-lag-throttler	boolean	Synonym to -enable_lag_throttler
--enable-tx-throttler	boolean	Synonym to -enable_tx_throttler
--enable-per-workload-table-metrics	boolean	Synonym to --enable_per_workload_table_metrics
--enable_consolidator	boolean	This option enables the query consolidator. (default true)
--enable_consolidator_replicas	boolean	This option enables the query consolidator only on replicas.
--enable_hot_row_protection	boolean	If true, incoming transactions for the same row (range) will be queued and cannot consume all txpool slots.
--enable_hot_row_protection_dry_run	boolean	If true, hot row protection is not enforced but logs if transactions would have been queued.
--enable_lag_throttler	boolean	If true, vttablet will run a throttler service, and will implicitly enable heartbeats
--enable_replication_reporter	boolean	Use polling to track replication lag.
--enable_transaction_limit	boolean	If true, limit on number of transactions open at the same time will be enforced for all users. User trying to open a new transaction after exhausting their limit will receive an error immediately, regardless of whether there are available slots or not.
--enable_transaction_limit_dry_run	boolean	If true, limit on number of transactions open at the same time will be tracked for all users, but not enforced.
--enable_tx_throttler	boolean	If true replication-lag-based throttling on transactions will be enabled.
--enable_per_workload_table_metrics	boolean	If true, query counts and query error metrics include a label that identifies the workload.
--enforce-tableacl-	config	if this flag is true, vttablet will fail to start if a valid tableacl config does not exist
--enforce_strict_trans_tables	boolean	If true, vttablet requires MySQL to run with STRICT_TRANS_TABLES or STRICT_ALL_TABLES on. It is recommended to not turn this flag off. Otherwise MySQL may alter your supplied values before saving them to the database. (default true)
--external-compressor	string	command with arguments to use when compressing a backup.
--external-compressor-extension	string	extension to use when using an external compressor.
--external-decompressor	string	command with arguments to use when decompressing a backup.
--file_backup_storage_root	string	Root directory for the file backup storage.
--filecustomrules	string	file based custom rule path
--filecustomrules_watch	boolean	set up a watch on the target file and reload query rules when it changes
--gc_check_interval	duration	Interval between garbage collection checks (default 1h0m0s)
--gc_purge_check_interval	duration	Interval between purge discovery checks (default 1m0s)
--gcs_backup_storage_bucket	string	Google Cloud Storage bucket to use for backups.
--gcs_backup_storage_root	string	Root prefix for all backup-related object names.
--gh-ost-path	string	override default gh-ost binary full path
--grpc_auth_mode	string	Which auth plugin implementation to use (eg: static)
--grpc_auth_mtls_allowed_substrings	string	List of substrings of at least one of the client certificate names (separated by colon).
--grpc_auth_static_client_creds	string	When using grpc_static_auth in the server, this file provides the credentials to use to authenticate with server.
--grpc_auth_static_password_file	string	JSON File to read the users/passwords from.
--grpc_ca	string	server CA to use for gRPC connections, requires TLS, and enforces client certificate check
--grpc_cert	string	server certificate to use for gRPC connections, requires grpc_key, enables TLS
--grpc_compression	string	Which protocol to use for compressing gRPC. Default: nothing. Supported: snappy
--grpc_crl	string	path to a certificate revocation list in PEM format, client certificates will be further verified against this file during TLS handshake
--grpc_enable_optional_tls	boolean	enable optional TLS mode when a server accepts both TLS and plain-text connections on the same port
--grpc_enable_tracing	boolean	Enable gRPC tracing.
--grpc_initial_conn_window_size	int	gRPC initial connection window size
--grpc_initial_window_size	int	gRPC initial window size
--grpc_keepalive_time	duration	After a duration of this time, if the client doesn't see any activity, it pings the server to see if the transport is still alive. (default 10s)
--grpc_keepalive_timeout	duration	After having pinged for keepalive check, the client waits for a duration of Timeout and if no activity is seen even after that the connection is closed. (default 10s)
--grpc_key	string	server private key to use for gRPC connections, requires grpc_cert, enables TLS
--grpc_max_connection_age	duration	Maximum age of a client connection before GoAway is sent. (default 2562047h47m16.854775807s)
--grpc_max_connection_age_grace	duration	Additional grace period after grpc_max_connection_age, after which connections are forcibly closed. (default 2562047h47m16.854775807s)
--grpc_max_message_size	int	Maximum allowed RPC message size. Larger messages will be rejected by gRPC with the error 'exceeding the max size'. (default 16777216)
--grpc_port	int	Port to listen on for gRPC calls. If zero, do not listen.
--grpc_prometheus	boolean	Enable gRPC monitoring with Prometheus.
--grpc_server_ca	string	path to server CA in PEM format, which will be combine with server cert, return full certificate chain to clients
--grpc_server_initial_conn_window_size	int	gRPC server initial connection window size
--grpc_server_initial_window_size	int	gRPC server initial window size
--grpc_server_keepalive_enforcement_policy_min_time	duration	gRPC server minimum keepalive time (default 10s)
--grpc_server_keepalive_enforcement_policy_permit_without_stream	boolean	gRPC server permit client keepalive pings even when there are no active streams (RPCs)
--health_check_interval	duration	Interval between health checks (default 20s)
--heartbeat_enable	boolean	If true, vttablet records (if master) or checks (if replica) the current time of a replication heartbeat in the table _vt.heartbeat. The result is used to inform the serving state of the vttablet via healthchecks.
--heartbeat_interval	duration	How frequently to read and write replication heartbeat. (default 1s)
--heartbeat_on_demand_duration	duration	If non-zero, heartbeats are only written upon consumer request, and only run for up to given duration following the request. Frequent requests can keep the heartbeat running consistently; when requests are infrequent heartbeat may completely stop between requests
-h, --help	boolean	display usage and exit
--hot_row_protection_concurrent_transactions	int	Number of concurrent transactions let through to the txpool/MySQL for the same hot row. Should be > 1 to have enough 'ready' transactions in MySQL and benefit from a pipelining effect. (default 5)
--hot_row_protection_max_global_queue_size	int	Global queue limit across all row (ranges). Useful to prevent that the queue can grow unbounded. (default 1000)
--hot_row_protection_max_queue_size	int	Maximum number of BeginExecute RPCs which will be queued for the same row (range). (default 20)
--init_db_name_override	string	(init parameter) override the name of the db used by vttablet. Without this flag, the db name defaults to vt_
--init_keyspace	string	(init parameter) keyspace to use for this tablet
--init_populate_metadata	boolean	(init parameter) populate metadata tables even if restore_from_backup is disabled. If restore_from_backup is enabled, metadata tables are always populated regardless of this flag.
--init_shard	string	(init parameter) shard to use for this tablet
--init_tablet_type	string	(init parameter) the tablet type to use for this tablet.
--init_tags	StringMap	(init parameter) comma separated list of key:value pairs used to tag the tablet
--init_timeout	duration	(init parameter) timeout to use for the init phase. (default 1m0s)
--jaeger-agent-host	string	host and port to send spans to. if empty, no tracing will be done
--keep_logs	duration	keep logs for this long (using ctime) (zero to keep forever)
--keep_logs_by_mtime	duration	keep logs for this long (using mtime) (zero to keep forever)
--lameduck-period	duration	keep running at least this long after SIGTERM before stopping (default 50ms)
--lock-timeout	duration	Maximum time for which a shard/keyspace lock can be acquired for (default 45s)
--lock_tables_timeout	duration	How long to keep the table locked before timing out (default 1m0s)
--log_backtrace_at	traceLocation	when logging hits line file:N, emit a stack trace (default :0)
--log_dir	string	If non-empty, write log files in this directory
--log_err_stacks	boolean	log stack traces for errors
--log_queries	boolean	Enable query logging to syslog.
--log_queries_to_file	string	Enable query logging to the specified file
--log_rotate_max_size	uint	size in bytes at which logs are rotated (glog.MaxSize) (default 1887436800)
--logtostderr	boolean	log to standard error instead of files
--manifest-external-decompressor	string	command with arguments to store in the backup manifest when compressing a backup with an external compression engine.
--max-stack-size	int	configure the maximum stack size in bytes (default 67108864)
--max_concurrent_online_ddl	int	Maximum number of online DDL changes that may run concurrently (default 256)
--migration_check_interval	duration	Interval between migration checks (default 1m0s)
--mycnf-file	string	path to my.cnf, if reading all config params from there
--mycnf_bin_log_path	string	mysql binlog path
--mycnf_data_dir	string	data directory for mysql
--mycnf_error_log_path	string	mysql error log path
--mycnf_general_log_path	string	mysql general log path
--mycnf_innodb_data_home_dir	string	Innodb data home directory
--mycnf_innodb_log_group_home_dir	string	Innodb log group home directory
--mycnf_master_info_file	string	mysql master.info file
--mycnf_mysql_port	int	port mysql is listening on
--mycnf_pid_file	string	mysql pid file
--mycnf_relay_log_index_path	string	mysql relay log index path
--mycnf_relay_log_info_path	string	mysql relay log info path
--mycnf_relay_log_path	string	mysql relay log path
--mycnf_secure_file_priv	string	mysql path for loading secure files
--mycnf_server_id	int	mysql server id of the server (if specified, mycnf-file will be ignored)
--mycnf_slow_log_path	string	mysql slow query log path
--mycnf_socket_file	string	mysql socket file
--mycnf_tmp_dir	string	mysql tmp directory
--mysql_server_version	string	MySQL server version to advertise.
--mysqlctl_mycnf_template	string	template file to use for generating the my.cnf file during server init
--mysqlctl_socket	string	socket file to use for remote mysqlctl actions (empty for local actions)
--onclose_timeout	duration	wait no more than this for OnClose handlers before stopping (default 10s)
--onterm_timeout	duration	wait no more than this for OnTermSync handlers before stopping (default 10s)
--opentsdb_uri	string	URI of opentsdb /api/put method
--pid_file	string	If set, the process will write its pid to the named file, and delete it on graceful shutdown.
--pitr_gtid_lookup_timeout	duration	PITR restore parameter: timeout for fetching gtid from timestamp. (default 1m0s)
--pool_hostname_resolve_interval	duration	if set force an update to all hostnames and reconnect if changed, defaults to 0 (disabled)
--port	int	port for the server
--pprof	strings	enable profiling
--pt-osc-path	string	override default pt-online-schema-change binary full path
--publish_retry_interval	duration	how long vttablet waits to retry publishing the tablet record (default 30s)
--purge_logs_interval	duration	how often try to remove old logs (default 1h0m0s)
--query-log-stream-handler	string	URL handler for streaming queries log (default "/debug/querylog")
--querylog-filter-tag	string	string that must be present in the query for it to be logged; if using a value as the tag, you need to disable query normalization
--querylog-format	string	format for query logs ("text" or "json") (default "text")
--querylog-row-threshold	uint	Number of rows a query has to return or affect before being logged; not useful for streaming queries. 0 means all queries will be logged.
--queryserver-config-acl-exempt-acl	string	an acl that exempt from table acl checking (this acl is free to access any vitess tables).
--queryserver-config-annotate-queries	boolean	prefix queries to MySQL backend with comment indicating vtgate principal (user) and target tablet type
--queryserver-config-enable-table-acl-dry-run	boolean	If this flag is enabled, tabletserver will emit monitoring metrics and let the request pass regardless of table acl check results
--queryserver-config-idle-timeout	float	query server idle timeout (in seconds), vttablet manages various mysql connection pools. This config means if a connection has not been used in given idle timeout, this connection will be removed from pool. This effectively manages number of connection objects and optimize the pool performance. (default 1800)
--queryserver-config-max-result-size	int	query server max result size, maximum number of rows allowed to return from vttablet for non-streaming queries. (default 10000)
--queryserver-config-message-postpone-cap	int	query server message postpone cap is the maximum number of messages that can be postponed at any given time. Set this number to substantially lower than transaction cap, so that the transaction pool isn't exhausted by the message subsystem. (default 4)
--queryserver-config-olap-transaction-timeout	float	query server transaction timeout (in seconds), after which a transaction in an OLAP session will be killed (default 30)
--queryserver-config-passthrough-dmls	boolean	query server pass through all dml statements without rewriting
--queryserver-config-pool-conn-max-lifetime	float	query server connection max lifetime (in seconds), vttablet manages various mysql connection pools. This config means if a connection has lived at least this long, it connection will be removed from pool upon the next time it is returned to the pool.
--queryserver-config-pool-size	int	query server read pool size, connection pool is used by regular queries (non streaming, not in a transaction) (default 16)
--queryserver-config-query-cache-lfu	boolean	query server cache algorithm. when set to true, a new cache algorithm based on a TinyLFU admission policy will be used to improve cache behavior and prevent pollution from sparse queries (default true)
--queryserver-config-query-cache-memory	int	query server query cache size in bytes, maximum amount of memory to be used for caching. vttablet analyzes every incoming query and generate a query plan, these plans are being cached in a lru cache. This config controls the capacity of the lru cache. (default 33554432)
--queryserver-config-query-cache-size	int	query server query cache size, maximum number of queries to be cached. vttablet analyzes every incoming query and generate a query plan, these plans are being cached in a lru cache. This config controls the capacity of the lru cache. (default 5000)
--queryserver-config-query-pool-timeout	float	query server query pool timeout (in seconds), it is how long vttablet waits for a connection from the query pool. If set to 0 (default) then the overall query timeout is used instead.
--queryserver-config-query-pool-waiter-cap	int	query server query pool waiter limit, this is the maximum number of queries that can be queued waiting to get a connection (default 5000)
--queryserver-config-query-timeout	float	query server query timeout (in seconds), this is the query timeout in vttablet side. If a query takes more than this timeout, it will be killed. (default 30)
--queryserver-config-schema-change-signal	boolean	query server schema signal, will signal connected vtgates that schema has changed whenever this is detected. VTGates will need to have -schema_change_signal enabled for this to work (default true)
--queryserver-config-schema-reload-time	float	query server schema reload time, how often vttablet reloads schemas from underlying MySQL instance in seconds. vttablet keeps table schemas in its own memory and periodically refreshes it from MySQL. This config controls the reload time. (default 1800)
--queryserver-config-stream-buffer-size	int	query server stream buffer size, the maximum number of bytes sent from vttablet for each stream call. It's recommended to keep this value in sync with vtgate's stream_buffer_size. (default 32768)
--queryserver-config-stream-pool-size	int	query server stream connection pool size, stream pool is used by stream queries: queries that return results to client in a streaming fashion (default 200)
--queryserver-config-stream-pool-timeout	float	query server stream pool timeout (in seconds), it is how long vttablet waits for a connection from the stream pool. If set to 0 (default) then there is no timeout.
--queryserver-config-stream-pool-waiter-cap	int	query server stream pool waiter limit, this is the maximum number of streaming queries that can be queued waiting to get a connection
--queryserver-config-strict-table-	acl	only allow queries that pass table acl checks
--queryserver-config-terse-errors	boolean	prevent bind vars from escaping in client error messages
--queryserver-config-transaction-cap	int	query server transaction cap is the maximum number of transactions allowed to happen at any given point of a time for a single vttablet. E.g. by setting transaction cap to 100, there are at most 100 transactions will be processed by a vttablet and the 101th transaction will be blocked (and fail if it cannot get connection within specified timeout) (default 20)
--queryserver-config-transaction-timeout	float	query server transaction timeout (in seconds), a transaction will be killed if it takes longer than this value (default 30)
--queryserver-config-truncate-error-len	int	truncate errors sent to client if they are longer than this value (0 means do not truncate)
--queryserver-config-txpool-timeout	float	query server transaction pool timeout, it is how long vttablet waits if tx pool is full (default 1)
--queryserver-config-txpool-waiter-cap	int	query server transaction pool waiter limit, this is the maximum number of transactions that can be queued waiting to get a connection (default 5000)
--queryserver-config-warn-result-size	int	query server result size warning threshold, warn if number of rows returned from vttablet for non-streaming queries exceeds this
--queryserver-enable-settings-pool	boolean	Enable pooling of connections with modified system settings (default true)
--queryserver-enable-views	boolean	Enable views support in vttablet.
--queryserver_enable_online_ddl	boolean	Enable online DDL. (default true)
--redact-debug-ui-queries	boolean	redact full queries and bind variables from debug UI
--relay_log_max_items	int	Maximum number of rows for VReplication target buffering. (default 5000)
--relay_log_max_size	int	Maximum buffer size (in bytes) for VReplication target buffering. If single rows are larger than this, a single row is buffered at a time. (default 250000)
--remote_operation_timeout	duration	time to wait for a remote operation (default 15s)
--replication_connect_retry	duration	how long to wait in between replica reconnect attempts. Only precise to the second. (default 10s)
--restore_concurrency	int	(init restore parameter) how many concurrent files to restore at once (default 4)
--restore_from_backup	boolean	(init restore parameter) will check BackupStorage for a recent backup at startup and start there
--restore_from_backup_ts	string	(init restore parameter) if set, restore the latest backup taken at or before this timestamp. Example: '2021-04-29.133050'
--retain_online_ddl_tables	duration	How long should vttablet keep an old migrated table before purging it (default 24h0m0s)
--s3_backup_aws_endpoint	string	endpoint of the S3 backend (region must be provided).
--s3_backup_aws_region	string	AWS region to use. (default "us-east-1")
--s3_backup_aws_retries	int	AWS request retries. (default -1)
--s3_backup_force_path_style	boolean	force the s3 path style.
--s3_backup_log_level	string	determine the S3 loglevel to use from LogOff, LogDebug, LogDebugWithSigning, LogDebugWithHTTPBody, LogDebugWithRequestRetries, LogDebugWithRequestErrors. (default "LogOff")
--s3_backup_server_side_encryption	string	server-side encryption algorithm (e.g., AES256, aws:kms, sse_c:/path/to/key/file).
--s3_backup_storage_bucket	string	S3 bucket to use for backups.
--s3_backup_storage_root	string	root prefix for all backup-related object names.
--s3_backup_tls_skip_verify_cert	boolean	skip the 'certificate is valid' check for SSL connections.
--sanitize_log_messages	boolean	Remove potentially sensitive information in tablet INFO, WARNING, and ERROR log messages such as query parameters.
--schema-change-reload-timeout	duration	query server schema change reload timeout, this is how long to wait for the signaled schema reload operation to complete before giving up (default 30s)
--schema-version-max-age-seconds	int	Max age of schema version records to kept in memory by the vreplication historian
--security_policy	string	the name of a registered security policy to use for controlling access to URLs - empty means allow all for anyone (built-in policies: deny-all, read-only)
--service_map	strings	comma separated list of services to enable (or disable if prefixed with '-') Example: grpc-queryservice
--serving_state_grace_period	duration	how long to pause after broadcasting health to vtgate, before enforcing a new serving state
--shard_sync_retry_delay	duration	delay between retries of updates to keep the tablet and its shard record in sync (default 30s)
--shutdown_grace_period	float	how long to wait (in seconds) for queries and transactions to complete during graceful shutdown.
--sql-max-length-errors	int	truncate queries in error logs to the given length (default unlimited)
--sql-max-length-ui	int	truncate queries in debug UIs to the given length (default 512) (default 512)
--srv_topo_cache_refresh	duration	how frequently to refresh the topology for cached entries (default 1s)
--srv_topo_cache_ttl	duration	how long to use cached entries for topology (default 1s)
--srv_topo_timeout	duration	topo server timeout (default 5s)
--stats_backend	string	The name of the registered push-based monitoring/stats backend to use
--stats_combine_dimensions	string	List of dimensions to be combined into a single "all" value in exported stats vars
--stats_common_tags	strings	Comma-separated list of common tags for the stats backend. It provides both label and values. Example: label1:value1,label2:value2
--stats_drop_variables	string	Variables to be dropped from the list of exported variables.
--stats_emit_period	duration	Interval between emitting stats to all registered backends (default 1m0s)
--statsd_address	string	Address for statsd client
--statsd_sample_rate	float	Sample rate for statsd metrics (default 1)
--stderrthreshold	severity	logs at or above this threshold go to stderr (default 1)
--stream_health_buffer_size	uint	max streaming health entries to buffer per streaming health client (default 20)
--table-acl-config	string	path to table access checker config file; send SIGHUP to reload this file
--table-acl-config-reload-interval	duration	Ticker to reload ACLs. Duration flag, format e.g.: 30s. Default: do not reload
--table_gc_lifecycle	string	States for a DROP TABLE garbage collection cycle. Default is 'hold,purge,evac,drop', use any subset ('drop' implcitly always included) (default "hold,purge,evac,drop")
--tablet-path	string	tablet alias
--tablet_config	string	YAML file config for tablet
--tablet_dir	string	The directory within the vtdataroot to store vttablet/mysql files. Defaults to being generated by the tablet uid.
--tablet_grpc_ca	string	the server ca to use to validate servers when connecting
--tablet_grpc_cert	string	the cert to use to connect
--tablet_grpc_crl	string	the server crl to use to validate server certificates when connecting
--tablet_grpc_key	string	the key to use to connect
--tablet_grpc_server_name	string	the server name to use to validate server certificate
--tablet_hostname	string	if not empty, this hostname will be assumed instead of trying to resolve it
--tablet_manager_grpc_ca	string	the server ca to use to validate servers when connecting
--tablet_manager_grpc_cert	string	the cert to use to connect
--tablet_manager_grpc_concurrency	int	concurrency to use to talk to a vttablet server for performance-sensitive RPCs (like ExecuteFetchAs{Dba,AllPrivs,App}) (default 8)
--tablet_manager_grpc_connpool_size	int	number of tablets to keep tmclient connections open to (default 100)
--tablet_manager_grpc_crl	string	the server crl to use to validate server certificates when connecting
--tablet_manager_grpc_key	string	the key to use to connect
--tablet_manager_grpc_server_name	string	the server name to use to validate server certificate
--tablet_manager_protocol	string	Protocol to use to make tabletmanager RPCs to vttablets. (default "grpc")
--tablet_protocol	string	Protocol to use to make queryservice RPCs to vttablets. (default "grpc")
--throttle_check_as_check_self	boolean	Should throttler/check return a throttler/check-self result (changes throttler behavior for writes)
--throttle_metrics_query	SELECT	Override default heartbeat/lag metric. Use either SELECT (must return single row, single value) or `SHOW GLOBAL ... LIKE ...` queries. Set -throttle_metrics_threshold respectively.
--throttle_metrics_threshold	float	Override default throttle threshold, respective to -throttle_metrics_query (default 1.7976931348623157e+308)
--throttle_tablet_types	string	Comma separated VTTablet types to be considered by the throttler. default: 'replica'. example: 'replica,rdonly'. 'replica' aways implicitly included (default "replica")
--throttle_threshold	duration	Replication lag threshold for default lag throttling (default 1s)
--throttler-config-via-topo	boolean	When 'true', read config from topo service and ignore throttle_threshold, throttle_metrics_threshold, throttle_metrics_query, throttle_check_as_check_self
--topo_consul_lock_delay	duration	LockDelay for consul session. (default 15s)
--topo_consul_lock_session_checks	string	List of checks for consul session. (default "serfHealth")
--topo_consul_lock_session_ttl	string	TTL for consul session.
--topo_consul_watch_poll_duration	duration	time of the long poll for watch queries. (default 30s)
--topo_etcd_lease_ttl	int	Lease TTL for locks and leader election. The client will use KeepAlive to keep the lease going. (default 30)
--topo_etcd_tls_ca	string	path to the ca to use to validate the server cert when connecting to the etcd topo server
--topo_etcd_tls_cert	string	path to the client cert to use to connect to the etcd topo server, requires topo_etcd_tls_key, enables TLS
--topo_etcd_tls_key	string	path to the client key to use to connect to the etcd topo server, enables TLS
--topo_global_root	string	the path of the global topology data in the global topology server
--topo_global_server_address	string	the address of the global topology server
--topo_implementation	string	the topology implementation to use
--topo_k8s_context	string	The kubeconfig context to use, overrides the 'current-context' from the config
--topo_k8s_kubeconfig	string	Path to a valid kubeconfig file. When running as a k8s pod inside the same cluster you wish to use as the topo, you may omit this and the below arguments, and Vitess is capable of auto-discovering the correct values. https://kubernetes.io/docs/tasks/access-application-cluster/access-cluster/#accessing-the-api-from-a-pod
--topo_k8s_namespace	string	The kubernetes namespace to use for all objects. Default comes from the context or in-cluster config
--topo_zk_auth_file	string	auth to use when connecting to the zk topo server, file contents should be :, e.g., digest:user:pass
--topo_zk_base_timeout	duration	zk base timeout (see zk.Connect) (default 30s)
--topo_zk_max_concurrency	int	maximum number of pending requests to send to a Zookeeper server. (default 64)
--topo_zk_tls_ca	string	the server ca to use to validate servers when connecting to the zk topo server
--topo_zk_tls_cert	string	the cert to use to connect to the zk topo server, requires topo_zk_tls_key, enables TLS
--topo_zk_tls_key	string	the key to use to connect to the zk topo server, enables TLS
--topocustomrule_cell	string	topo cell for customrules file. (default "global")
--topocustomrule_path	string	path for customrules file. Disabled if empty.
--tracer	string	tracing service to use (default "noop")
--tracing-enable-logging	boolean	whether to enable logging in the tracing service
--tracing-sampling-rate	float	sampling rate for the probabilistic jaeger sampler (default 0.1)
--tracing-sampling-type	string	sampling strategy to use for jaeger. possible values are 'const', 'probabilistic', 'rateLimiting', or 'remote' (default "const")
--track_schema_versions	boolean	When enabled, vttablet will store versions of schemas at each position that a DDL is applied and allow retrieval of the schema corresponding to a position
--transaction-log-stream-handler	string	URL handler for streaming transactions log (default "/debug/txlog")
--transaction_limit_by_component	boolean	Include CallerID.component when considering who the user is for the purpose of transaction limit.
--transaction_limit_by_principal	boolean	Include CallerID.principal when considering who the user is for the purpose of transaction limit. (default true)
--transaction_limit_by_subcomponent	boolean	Include CallerID.subcomponent when considering who the user is for the purpose of transaction limit.
--transaction_limit_by_username	boolean	Include VTGateCallerID.username when considering who the user is for the purpose of transaction limit. (default true)
--transaction_limit_per_user	float	Maximum number of transactions a single user is allowed to use at any time, represented as fraction of -transaction_cap. (default 0.4)
--twopc_abandon_age	float	time in seconds. Any unresolved transaction older than this time will be sent to the coordinator to be resolved.
--twopc_coordinator_address	string	address of the (VTGate) process(es) that will be used to notify of abandoned transactions.
--twopc_enable	boolean	if the flag is on, 2pc is enabled. Other 2pc flags must be supplied.
--tx-throttler-config	string	Synonym to -tx_throttler_config (default "target_replication_lag_sec: 2\nmax_replication_lag_sec: 10\ninitial_rate: 100\nmax_increase: 1\nemergency_decrease: 0.5\nmin_duration_between_increases_sec: 40\nmax_duration_between_increases_sec: 62\nmin_duration_between_decreases_sec: 20\nspread_backlog_across_sec: 20\nage_bad_rate_after_sec: 180\nbad_rate_increase: 0.1\nmax_rate_approach_threshold: 0.9\n")
--tx-throttler-default-priority int	int	Default query priority used by the transaction throttler if it is not specified in a query comment directive. It must be a number between 0 (highest priority) and 100 (lowest priority) (default: 100)
--tx-throttler-healthcheck-cells	strings	Synonym to -tx_throttler_healthcheck_cells
--tx-throttler-tablet-types	strings	A comma-separated list of tablet types. Only tablets of this type are monitored for replication lag by the transaction throttler. Supported types are replica and/or rdonly. (default replica)
--tx_throttler_config	string	The configuration of the transaction throttler as a text formatted throttlerdata.Configuration protocol buffer message (default "target_replication_lag_sec: 2\nmax_replication_lag_sec: 10\ninitial_rate: 100\nmax_increase: 1\nemergency_decrease: 0.5\nmin_duration_between_increases_sec: 40\nmax_duration_between_increases_sec: 62\nmin_duration_between_decreases_sec: 20\nspread_backlog_across_sec: 20\nage_bad_rate_after_sec: 180\nbad_rate_increase: 0.1\nmax_rate_approach_threshold: 0.9\n")
--tx_throttler_healthcheck_cells	strings	A comma-separated list of cells. Only tabletservers running in these cells will be monitored for replication lag by the transaction throttler.
--unhealthy_threshold	duration	replication lag after which a replica is considered unhealthy (default 2h0m0s)
--v	Level	log level for V logs
-v, --version	boolean	print binary version
--vmodule	moduleSpec	comma-separated list of pattern=N settings for file-filtered logging
--vreplication-parallel-insert-workers	int	Number of parallel insertion workers to use during copy phase. Set <= 1 to disable parallelism, or > 1 to enable concurrent insertion during copy phase. (default 1)
--vreplication_copy_phase_duration	duration	Duration for each copy phase loop (before running the next catchup: default 1h) (default 1h0m0s)
--vreplication_copy_phase_max_innodb_history_list_length	int	The maximum InnoDB transaction history that can exist on a vstreamer (source) before starting another round of copying rows. This helps to limit the impact on the source tablet. (default 1000000)
--vreplication_copy_phase_max_mysql_replication_lag	int	The maximum MySQL replication lag (in seconds) that can exist on a vstreamer (source) before starting another round of copying rows. This helps to limit the impact on the source tablet. (default 43200)
--vreplication_experimental_flags	int	(Bitmask) of experimental features in vreplication to enable (default 1)
--vreplication_healthcheck_retry_delay	duration	healthcheck retry delay (default 5s)
--vreplication_healthcheck_timeout	duration	healthcheck retry delay (default 1m0s)
--vreplication_healthcheck_topology_refresh	duration	refresh interval for re-reading the topology (default 30s)
--vreplication_heartbeat_update_interval	int	Frequency (in seconds, default 1, max 60) at which the time_updated column of a vreplication stream when idling (default 1)
--vreplication_max_time_to_retry_on_error	duration	stop automatically retrying when we've had consecutive failures with the same error for this long after the first occurrence
--vreplication_replica_lag_tolerance	duration	Replica lag threshold duration: once lag is below this we switch from copy phase to the replication (streaming) phase (default 1m0s)
--vreplication_retry_delay	duration	delay before retrying a failed workflow event in the replication phase (default 5s)
--vreplication_store_compressed_gtid	boolean	Store compressed gtids in the pos column of _vt.vreplication
--vreplication_tablet_type	string	comma separated list of tablet types used as a source (default "in_order:REPLICA,PRIMARY")
--vstream-binlog-rotation-threshold	int	Byte size at which a VStreamer will attempt to rotate the source's open binary log before starting a GTID snapshot based stream (e.g. a ResultStreamer or RowStreamer) (default 67108864)
--vstream_dynamic_packet_size	boolean	Enable dynamic packet sizing for VReplication. This will adjust the packet size during replication to improve performance. (default true)
--vstream_packet_size	int	Suggested packet size for VReplication streamer. This is used only as a recommendation. The actual packet size may be more or less than this amount. (default 250000)
--vtgate_protocol	string	how to talk to vtgate (default "grpc")
--vttablet_skip_buildinfo_tags	string	comma-separated list of buildinfo tags to skip from merging with --init_tags. each tag is either an exact match or a regular expression of the form '/regexp/'. (default "/.*/")
--wait_for_backup_interval	duration	(init restore parameter) if this is greater than 0, instead of starting up empty when no backups are found, keep checking at this interval for a backup to appear
--watch_replication_stream	boolean	When enabled, vttablet will stream the MySQL replication stream from the local server, and use it to update schema when it sees a DDL.
--xbstream_restore_flags	string	Flags to pass to xbstream command during restore. These should be space separated and will be added to the end of the command. These need to match the ones used for backup e.g. --compress / --decompress, --encrypt / --decrypt
--xtrabackup_backup_flags	string	Flags to pass to backup command. These should be space separated and will be added to the end of the command
--xtrabackup_prepare_flags	string	Flags to pass to prepare command. These should be space separated and will be added to the end of the command
--xtrabackup_root_path	string	Directory location of the xtrabackup and xbstream executables, e.g., /usr/bin
--xtrabackup_stream_mode	string	Which mode to use if streaming, valid values are tar and xbstream. Please note that tar is not supported in XtraBackup 8.0 (default "tar")
--xtrabackup_stripe_block_size	uint	Size in bytes of each block that gets sent to a given stripe before rotating to the next stripe (default 102400)
--xtrabackup_stripes	uint	If greater than 0, use data striping across this many destination files to parallelize data transfer and decompression
--xtrabackup_user	string	User that xtrabackup will use to connect to the database server. This user must have all necessary privileges. For details, please refer to xtrabackup documentation.

Key Options #

--restore_from_backup: The default value for this flag is false. If set to true, and the my.cnf file was successfully loaded, then vttablet can perform automatic restores as follows:
- If started against a mysql instance that has no data files, it will search the list of backups for the latest one, and initiate a restore. After this, it will point the mysql to the current primary and wait for replication to catch up. Once replication is caught up to the specified tolerance limit, it will advertise itself as serving. This will cause the vtgates to add it to the list of healthy tablets to serve queries from.
- If this flag is true, but my.cnf was not loaded, then vttablet will fatally exit with an error message.
- You can additionally control the level of concurrency for a restore with the --restore_concurrency flag. This is typically useful in cloud environments to prevent the restore process from becoming a 'noisy' neighbor by consuming all available disk IOPS.

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