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Cluster Component Tables

This section includes information schema tables that fall into two categories: those that contain information about the status of cluster components and distribution of data accross them, and others that contain information for the purpose of MySQL compatibility.

information_schema.AGGREGATORS

This table contains information about aggregators. It is useful for understanding the number and attributes of the aggregators for a given cluster.

Column Name Description
HOST The hostname or IP address for the related aggregator.
PORT The port number of the related aggregator.
STATE The current state of a given aggregator.
OPENED_CONNECTIONS The number of connections opened on a given aggregator.
AVERAGE_ROUNDTRIP_LATENCY The average ping roundtrip latency in milliseconds for a given aggregator.
MASTER_AGGREGATOR If a given aggregator is in the role of master, this will be 1, otherwise 0.
ROLE Whether a given aggregator is a master or child. This will be leader for master aggregators, and follower for children.
NODE_ID The unique ID of a given aggregator node.

information_schema.CHARACTER_SETS

This table stores information about available character sets.

Column Name Description
CHARACTER_SET_NAME The character set name.
DEFAULT_COLLATE_NAME Default collation for a given character set.
DESCRIPTION Description of the character set.
MAXLEN The maximum number of bytes required to store one charcter of a given character set.

information_schema.COLLATIONS

This tables stores information about collations for each character set.

Column Name Description
COLLATION_NAME The collation name.
CHARACTER_SET_NAME The name of the associated character set for a given collation.
ID The unique ID for a given collation.
IS_DEFAULT YES if given collation is a the default for its character set, otherwise blank.
IS_COMPILED Whether or not the character set is fully compiled.
SORTLEN The amount of memory, in bytes, required in order for strings of a given character set to be sorted.

information_schema.COLLATION_CHARACTER_SET_APPLICABILITY

This table stores information about the available collations for each character set.

Column Name Description
COLLATION_NAME The collation name.
CHARACTER_SET_NAME The name of the associated character set for a given collation.

information_schema.COLUMNAR_SEGMENTS

This view stores information about each columnar_segment (column segment).

Column Name Description
DATABASE_NAME The name of the related database.
TABLE_NAME The name of the related table.
COLUMN_NAME The name of the related column.
SEGMENT_ID The ID of a given segment.
COLUMN_ID The ID of the related column.
FILE The name of the file directory where a given segment is stored.
HOST The hostname or IP address for the related leaf node.
PORT The port number of the related leaf node.
NODE_ID The ID of the related leaf node.
PARTITION The ID of the partition on which a given segment is stored.
ROWS_COUNT The number of rows in a given segement.
DELETED_ROWS_COUNT The number of deleted rows in a given segment.
ENCODING The encoding for a given column.
MIN_VALUE The minimum value of a given column in the segment.
MAX_VALUE The maximum value of a given column in the segment.
SEGMENT_MIN_VALUE The minimum value of the sort key column(s) in a given segment.
SEGMENT_MAX_VALUE The maximum value of the sort key column(s) in a given segment.
UNCOMPRESSED_SIZE The uncompressed size of a given columnar segment.
COMPRESSED_SIZE The compressed size of a given columnar segment.
CREATION_TIME The timestamp when a given columnstore file was created.
LSN Log sequence number of the related blob file.
TERM The term of the database, used to uniquely identify which node was the master of a specific database.
CHECKSUM The crc32c checksum of the file contents.
FILE_TYPE The type for a file where a given segment is stored.
OWNS_FILE Whether or not a corresponding file exists for a given column segement.
FILE_SIZE The size, in bytes, of a file where a given segment is stored.
FILE_OFFSET Specifies the offset in the file where a given segment is stored.

information_schema.COLUMNS

This table stores information about each column.

Column Name Description
TABLE_CATALOG The name of the catalog related to the table a given column belongs to.
TABLE_SCHEMA The name of the related database (schema) for a given column.
TABLE_NAME The name of the table a given column belongs to.
COLUMN_NAME The name of the column.
ORDINAL_POSITION The position of a given column among others in the table.
COLUMN_DEFAULT The default value of a given column.
IS_NULLABLE This value is YES if NULL values can be stored in the column, and NO if NULL values cannot be stored in the column.
IS_SPARSE Whether or not sparse compression is used on a given column.
DATA_TYPE The data type of a given column.
CHARACTER_MAXIMUM_LENGTH The maximum number of characters for a given string column.
CHARACTER_OCTET_LENGTH The maximum length, in bytes, for a given string column.
NUMERIC_PRECISION The numeric precision (maximum number of digits present in a number) for a given column.
NUMERIC_SCALE The numeric scale (maximum number of digits to the right the decimal point in a number) for a given column.
CHARACTER_SET_NAME The name of the character set of a given column.
COLLATION_NAME The collation name for the character set of a given column.
COLUMN_TYPE The data type of a given column.
COLUMN_KEY If this column is empty, the column is not indexed or the secondary column is a non-unique index. If the value in this column is MUL, multiple occurrences of the same value are allowed, and the column is the first included in a non-unique index. If the value of this column is PRI, it is either a primary key or one of multiple columns in a primary key. If the value of this column is UNI, it is the first column included in a unique index.
EXTRA Whether a given column was created with additional options such as auto_increment, that are included in the column_definition section of the CREATE TABLE syntax.
PRIVILEGES The privileges the current user has for a given column.
COLUMN_COMMENT Comments (if any) from the definition of a given column.

information_schema.DISTRIBUTED_DATABASES

This table contains information about databases.

Column Name Description
DATABASE_ID The unique ID of a given database.
DATABASE_NAME The name of a given database.
NUM_PARTITIONS The number of a partitions in a given database.
CLUSTER_ID The ID of the related cluster for a given database.
REMOTE_NAME The remote name of a given database.
IS_SYNC Determines if the database uses synchronous replication for high availability.
IS_SYNC_DURABILITY Determines if the database uses synchronous durability.
IS_PAUSED Whether DR replication of a given database is paused.

information_schema.DISTRIBUTED_PARTITIONS

This table contains information about partitions.

Column Name Description
DATABASE_ID The unique ID of the related database for a given partition.
ORDINAL The ordinal number for a given partition, which decides the order in which data is distributed among partitions.
HOST The hostname or IP address for the related node.
PORT The port number of the related node.
ROLE The role of the related node.
LOCKED Whether a given partition is locked, as part of a partition level lock or higher.
NODE_ID The ID of the related node.
IS_OFFLINE Whether a given partition is offline.
SYNC_DESIRED This is TRUE if a given partition instance uses synchronous replication. This matches the column IS_SYNC from information_schema.DISTRIBUTED_DATABASES of the corresponding database.
STATE The current state of a given partition. This can be EMPTY (for online masters), ASYNC, SYNC, READY or UNRECOVERABLE.
INSTANCE_ID Unique ID of the partition instance.
IS_READ_REPLICA Whether a given partition is part of a read replica or not.

information_schema.LEAVES

This table contains information about leaves.

Column Name Description
HOST The hostname or IP address for a given leaf node.
PORT The port number of a given leaf node.
AVAILABILITY_GROUP The ID of the related availability group.
PAIR_HOST The hostname or IP address for the mate of a given leaf which is part of a pair.
PAIR_PORT The port number of the mate of a given leaf which is part of a pair.
STATE The state of a given leaf node.
OPENED_CONNECTIONS The number of connections opened on a given leaf node.
AVERAGE_ROUNDTRIP_LATENCY The average ping roundtrip latency in milliseconds for a given leaf node.
NODE_ID The unique ID of a given leaf node.
GRACE_PERIOD_IN_SECONDS Time left for the node to recover after failing and coming back online. This is set by engine variable failover_initial_grace_interval_seconds.

information_schema.MV_CLUSTER_STATUS

This table stores information about partitions within a cluster. Learn more about interpreting this table in the SingleStore DB Components to Monitor guide.

Column Name Description
NODE_ID The ID of the related node.
HOST The hostname or IP address for the related leaf node.
PORT The port number of the related leaf node.
DATABASE_NAME The name of the related database.
ROLE The role of the related database (orphan, master, child, or reference).
STATE The state of the related database (online, offline, replicating).
POSITION A number indicating the position in the transaction log.
MASTER_HOST The hostname or IP address for the related master aggregator.
MASTER_PORT The port number of the related master aggregator.
METADATA_MASTER_NODE_ID The ID of the master aggregator node expected by the metadata.
METADATA_MASTER_HOST The hostname or IP address for the related master aggregator expected by the metadata.
METADATA_MASTER_PORT The port number of the related master aggregator expected by the metadata.
METADATA_ROLE The role of the related database expected by the metadata.
DETAILS An optional message about the current state.
COMMITTED_POSITION The position up to which each transaction has been committed. All pages in the log before this LSN are confirmed to be committed.
HARDENED_POSITION The current position in the transaction log on disk. All pages in the log before this LSN are written to disk.
REPLAY_POSITION The position up to which changes have been applied to replica. All pages before this LSN have been replayed into memory.

information_schema.MV_DISTRIBUTED_DATABASES_STATUS

This view contains information about the status of databases.

Column Name Description
DATABASE_NAME The name of a given related database.
NUM_PARTITIONS The number of partitions in a given database.
SUMMARY Exposes status of the database: healthy/degraded/offline.
ONLINE Whether a given database is online.
REPLICATING Whether a given database is replicating.
RECOVERING Whether a given database is recovering.
PENDING Whether a given database is pending.
TRANSITION Whether a given database is in transition.
UNRECOVERABLE Whether a given database is unrecoverable.
OFFLINE Whether a given database is offline.
SYNC_MISMATCH True if some partition instances are replicating in a mode different from the replication mode of the database.

information_schema.MV_EVENTS

This view contains information about events. It is useful for monitoring events across clusters over time. Learn more about interpreting this view in the SingleStore DB Components to Monitor guide.

Column Name Description
ORIGIN_NODE_ID The ID of the node from where a given event occurred.
EVENT_TIME The timestamp of a given event.
SEVERITY The severity of a given event: NOTICE, WARNING, or ERROR
EVENT_TYPE The type of event that occurred.
DETAILS Additional information about a given event in JSON format.

MV_EVENTS.EVENT_TYPE

This section provides descriptions for each potential result of SELECT DISTINCT EVENT_TYPE FROM information_schema.MV_EVENTS. Each result is one type of event occuring on the related node.

Event Type Description
NODE_STARTING The related node is starting up.
NODE_ONLINE The related node is online.
NODE_OFFLINE The related node is offline.
NODE_ATTACHING The related node is attaching.
NODE_DETACHED The related node is detaching.
LEAF_ADD A leaf node is being added to the cluster.
LEAF_REMOVE A leaf node is being removed from the cluster.
AGGREGATOR_ADD An aggregator is being added to the cluster.
AGGREGATOR_REMOVE An aggregator is being removed from the cluster.
DATABASE_REPLICATION_START Replication of the database is started.
DATABASE_REPLICATION_STOP Replication of the database is stopped.
REBALANCE_STARTED Rebalance operations have started.
REBALANCE_FINISHED Rebalance operations have finished.
NOTIFY_AGGREGATOR_PROMOTED The related node has been notified of an aggregator being promoted from child to master.
NODE_REACHABLE The related node has become reachable.
NODE_UNREACHABLE The related node has become unreachable.
SYSTEM_VAR_CHANGED An engine variable was reconfigured.
HEARTBEAT_QUERY_FAILURE A heartbeat query failed.
NODE_MEMORY_VIOLATION The available memory for the related node has gone below the desired threshold. The engine variable node_memory_low_threshold_mb sets this threshold.
NODE_DISK_VIOLATION A warning that available disk space has gone below the desired threshold. The engine variable node_disk_low_threshold_mb sets this threshold.
NODE_PING_VIOLATION A warning that the network ping latency for a node has increased above the allowed threshold. See node_ping_latency_high_threshold_ms.
BACKUP_DB The related database, and therefore the given node, has been backed up.
RESTORE_DB A backup of the related database, and therefore the given node, has been restored.
MAX_MEMORY Maximum server memory has been hit.
MAX_TABLE_MEMORY Maximum table memory has been hit.
MAX_MEMORY_ON_REPLAY This means that replicate operations ran out of memory, stopping replay.
PARTITION_UNRECOVERABLE A partition is lost due to failure and no longer can be recovered.
WORKLOAD_THROTTLE
PIPELINE_STOPPED A pipeline stopped.
INGEST_ERRORS_OUT_OF_DISK Ingest is failing due to low disk space available.
DATABASE_REPROVISION The related database is being reprovisioned.

information_schema.MV_HOSTS_INFORMATION

This view contains information about hosts.

Column Name Description
IP_ADDR The IP address of a given host.
SYSTEM_MEMORY_MB The memory, in MB, of a given host.
SYSTEM_CPU_COUNT The number of CPUs a given host has.

information_schema.MV_NODES

This table contains information about nodes.

Column Name Description
ID The unique ID of a given node.
IP_ADDR The IP address of a given node.
PORT The port number of a given node.
TYPE The type of a given node.
STATE The state of a given node.
AVAILABILITY_GROUP The ID of the related availability group for a given node.
NUM_CPUS The number of CPUs available to a given node.
MAX_MEMORY_MB The maximum memory use, in MB, of a given node.
MEMORY_USED_MB The amount of memory, in MB, used by a given node.
TABLE_MEMORY_USED_MB The amount of memory, in MB, used by the related table(s) for a given node.
TOTAL_DISK_DATA_MB The total amount of disk data, in MB.
AVAILABLE_DATA_DISK The amount of available disk data, in MB.
UPTIME
VERSION The version of SingleStore that a given node is running on.

information_schema.PARAMETERS

This table contains information about parameters.

Column Name Description
SPECIFIC_CATALOG The name of the catalog that a given parameter belongs to.
SPECIFIC_SCHEMA The name of the related schema (database) for a given parameter.
SPECIFIC_NAME The name of the routine which contains a given parameter.
ORDINAL_POSITION The position of a given parameter among others in a given stored procedure or other object containing a parameter.
PARAMETER_MODE The mode of a given parameter.
PARAMETER_NAME The name of a given parameter.
DATA_TYPE The data type of a given parameter.
CHARACTER_MAXIMUM_LENGTH The maximum length, in characters, for a given string parameter.
CHARACTER_OCTET_LENGTH The maximum length, in bytes, for a given string parameter.
NUMERIC_PRECISION The numeric precision (maximum number of digits present in a number) for a given parameter.
NUMERIC_SCALE The numeric scale (maximum number of digits to the right the decimal point in a number) for a given parameter.
CHARACTER_SET_NAME The name of the related character set for a given parameter.
COLLATION_NAME The name of the related collation for a given parameter.
DTD_IDENTIFIER This field contains the datatype of a given parameter, as well as other low level information.
ROUTINE_TYPE The type of routine a given parameter is associated with: PROCEDURE or FUNCTION.

information_schema.ROUTINES

This table contains information about routines in a cluster.

Column Name Description
SPECIFIC_NAME The name of a given routine.
ROUTINE_CATALOG The related catalog for a given routine.
ROUTINE_SCHEMA The related schema (database) for a given routine.
ROUTINE_NAME The name of a given routine.
ROUTINE_TYPE The type of routine a given parameter is associated with: PROCEDURE or FUNCTION.
DATA_TYPE The datatype of a given routine. If a routine is the PROCEDURE type, this column is NULL.
CHARACTER_MAXIMUM_LENGTH The maximum length, in number of characters, returned by a given routine. If a routine is the PROCEDURE type, this column is NULL.
CHARACTER_OCTET_LENGTH The maximum length, in bytes, returned by a given routine. If a routine is the PROCEDURE type, this column is NULL.
NUMERIC_PRECISION The numeric precision (maximum number of digits present in a number) for the return of a given routine. If a routine is the PROCEDURE type, this column is NULL.
NUMERIC_SCALE The numeric scale (maximum number of digits to the right the decimal point in a number) for the return to a given routine. If a routine is the PROCEDURE type, this column is NULL.
CHARACTER_SET_NAME The related character set name returned by a given routine. If a routine is the PROCEDURE type, this column is NULL.
COLLATION_NAME The related collation name returned by a given routine. If a routine is the PROCEDURE type, this column is NULL.
DTD_IDENTIFIER The datatype returned by a given routine. If a routine is the PROCEDURE type, this column is NULL.
ROUTINE_BODY The language used to define a given routine. This value is always SQL.
ROUTINE_DEFINITION The SQL statement executed by a given routine.
EXTERNAL_NAME This value is always NULL.
EXTERNAL_LANGUAGE The language of the routine. This value is always SQL.
PARAMETER_STYLE This value is always SQL.
SQL_PATH This value is always NULL.
SECURITY_TYPE This value is always DEFINER.
CREATED The timestamp at which a given routine was created.
LAST_ALTERED The timestamp at which a given routine was last updated.
SQL_MODE The setting of the SQL_mode engine variable at the creation of a given routine.
ROUTINE_COMMENT Comments (if any) left during the creation of a given routine.
DEFINER The user who created a given routine.
CHARACTER_SET_CLIENT The setting of the character_set_client engine variable at the creation of a given routine.
COLLATION_CONNECTION The setting of the collation_connection engine variable at the creation of a given routine.
DATABASE_COLLATION The related collation for a given routine.

information_schema.SCHEMATA

This table contains information about schemas (databases).

Column Name Description
CATALOG_NAME The name of the related catalog for a given database.
SCHEMA_NAME The name of a given database.
DEFAULT_CHARACTER_SET_NAME The name of the default character set for a given database.
DEFAULT_COLLATION_NAME The name of the default collation for a given database.
SQL_PATH This value is always NULL.

information_schema.SITES

This table contains information about sites, and is available with SingleStore Managed Service.

Column Name Description
SITE_ID The unique ID of a given site.
SITE_NAME The name of a given site.

information_schema.TABLE_CONSTRAINTS

This table contains information about table constraints.

Column Name Description
CONSTRAINT_CATALOG The name of the related catalog for a given constraint.
CONSTRAINT_SCHEMA The name of the related schema (database) for a given constraint.
CONSTRAINT_NAME The name of a given constraint.
TABLE_SCHEMA The name of the related schema (database) for the table related to a given constraint.
TABLE_NAME The name of the realated table.
CONSTRAINT_TYPE The type of constraint.

information_schema.VIEWS

This table contains information about the views in a cluster.

Column Name Description
TABLE_CATALOG The related catalog for a given view.
TABLE_SCHEMA The related schema (database) for a given view.
TABLE_NAME The name of a given view.
VIEW_DEFINITION The SQL statement used to define a given view.
CHECK_OPTION This column exists for MySQL compatbility and is always NONE.
IS_UPDATABLE Whether or not a given view can be updated.
DEFINER The user who created a given view.
SECURITY_TYPE This value is always DEFINER.
CHARACTER_SET_CLIENT The session setting for the character_set_client engine variable when a given view was created.
COLLATION_CONNECTION The session setting for the collation_connection engine variable when a given view was created.