`MON$DATABASE`

MON$DATABASE displays the header information from the database the current user is connected to.

Column Name Data Type Description

Column Name	Data Type	Description
`MON$DATABASE_NAME`	`VARCHAR(255)`	The file name and full path of the primary database file, or the database alias
`MON$PAGE_SIZE`	`SMALLINT`	Database page size in bytes
`MON$ODS_MAJOR`	`SMALLINT`	Major ODS version, e.g., 11
`MON$ODS_MINOR`	`SMALLINT`	Minor ODS version, e.g., 2
`MON$OLDEST_TRANSACTION`	`BIGINT`	The number of the oldest [interesting] transaction (OIT)
`MON$OLDEST_ACTIVE`	`BIGINT`	The number of the oldest active transaction (OAT)
`MON$OLDEST_SNAPSHOT`	`BIGINT`	The number of the transaction that was active at the moment when the OAT was started — oldest snapshot transaction (OST)
`MON$NEXT_TRANSACTION`	`BIGINT`	The number of the next transaction, as it stood when the monitoring snapshot was taken
`MON$PAGE_BUFFERS`	`INTEGER`	The number of pages allocated in RAM for the database page cache
`MON$SQL_DIALECT`	`SMALLINT`	Database SQL Dialect: 1 or 3
`MON$SHUTDOWN_MODE`	`SMALLINT`	The current shutdown state of the database: `0` - the database is online `1` - multi-user shutdown `2` - single-user shutdown `3` - full shutdown
`MON$SWEEP_INTERVAL`	`INTEGER`	Sweep interval
`MON$READ_ONLY`	`SMALLINT`	Flag indicating whether the database is read-only (value 1) or read-write (value 0)
`MON$FORCED_WRITES`	`SMALLINT`	Indicates whether the write mode of the database is set for synchronous write (forced writes ON, value is 1) or asynchronous write (forced writes OFF, value is 0)
`MON$RESERVE_SPACE`	`SMALLINT`	The flag indicating reserve_space (value 1) or use_all_space (value 0) for filling database pages
`MON$CREATION_DATE`	`TIMESTAMP WITH TIME ZONE`	The date and time when the database was created or was last restored
`MON$PAGES`	`BIGINT`	The number of pages allocated for the database on an external device
`MON$STAT_ID`	`INTEGER`	Statistics identifier
`MON$BACKUP_STATE`	`SMALLINT`	Current physical backup (nBackup) state: `0` - normal `1` - stalled `2` - merge
`MON$CRYPT_PAGE`	`BIGINT`	Number of encrypted pages
`MON$OWNER`	`CHAR(63)`	Username of the database owner
`MON$SEC_DATABASE`	`CHAR(7)`	Displays what type of security database is used: `Default` - default security database, i.e. {secdb} `Self` - current database is used as security database `Other` - another database is used as security database (not itself or {secdb})
`MON$CRYPT_STATE`	`SMALLINT`	Current state of database encryption `0` - not encrypted `1` - encrypted `2` - decryption in progress `3` - encryption in progress
`MON$GUID`	`CHAR(38)`	Database GUID (persistent until restore/fixup)
`MON$FILE_ID`	`VARCHAR(255)`	Unique ID of the database file at the filesystem level
`MON$NEXT_ATTACHMENT`	`BIGINT`	Current value of the next attachment ID counter
`MON$NEXT_STATEMENT`	`BIGINT`	Current value of the next statement ID counter
`MON$REPLICA_MODE`	`SMALLINT`	Database replica mode `0` - not a replica `1` - read-only replica `2` - read-write replica

MON$DATABASE_NAME

VARCHAR(255)

The file name and full path of the primary database file, or the database alias

MON$PAGE_SIZE

SMALLINT

Database page size in bytes

MON$ODS_MAJOR

SMALLINT

Major ODS version, e.g., 11

MON$ODS_MINOR

SMALLINT

Minor ODS version, e.g., 2

MON$OLDEST_TRANSACTION

BIGINT

The number of the oldest [interesting] transaction (OIT)

MON$OLDEST_ACTIVE

BIGINT

The number of the oldest active transaction (OAT)

MON$OLDEST_SNAPSHOT

BIGINT

The number of the transaction that was active at the moment when the OAT was started — oldest snapshot transaction (OST)

MON$NEXT_TRANSACTION

BIGINT

The number of the next transaction, as it stood when the monitoring snapshot was taken

MON$PAGE_BUFFERS

INTEGER

The number of pages allocated in RAM for the database page cache

MON$SQL_DIALECT

SMALLINT

Database SQL Dialect: 1 or 3

MON$SHUTDOWN_MODE

SMALLINT

The current shutdown state of the database:

0 - the database is online
1 - multi-user shutdown
2 - single-user shutdown
3 - full shutdown

MON$SWEEP_INTERVAL

INTEGER

Sweep interval

MON$READ_ONLY

SMALLINT

Flag indicating whether the database is read-only (value 1) or read-write (value 0)

MON$FORCED_WRITES

SMALLINT

Indicates whether the write mode of the database is set for synchronous write (forced writes ON, value is 1) or asynchronous write (forced writes OFF, value is 0)

MON$RESERVE_SPACE

SMALLINT

The flag indicating reserve_space (value 1) or use_all_space (value 0) for filling database pages

MON$CREATION_DATE

TIMESTAMP WITH TIME ZONE

The date and time when the database was created or was last restored

MON$PAGES

BIGINT

The number of pages allocated for the database on an external device

MON$STAT_ID

INTEGER

Statistics identifier

MON$BACKUP_STATE

SMALLINT

Current physical backup (nBackup) state:

0 - normal
1 - stalled
2 - merge

MON$CRYPT_PAGE

BIGINT

Number of encrypted pages

MON$OWNER

CHAR(63)

Username of the database owner

MON$SEC_DATABASE

CHAR(7)

Displays what type of security database is used:

Default - default security database, i.e. {secdb}
Self - current database is used as security database
Other - another database is used as security database (not itself or {secdb})

MON$CRYPT_STATE

SMALLINT

Current state of database encryption

0 - not encrypted
1 - encrypted
2 - decryption in progress
3 - encryption in progress

MON$GUID

CHAR(38)

Database GUID (persistent until restore/fixup)

MON$FILE_ID

VARCHAR(255)

Unique ID of the database file at the filesystem level

MON$NEXT_ATTACHMENT

BIGINT

Current value of the next attachment ID counter

MON$NEXT_STATEMENT

BIGINT

Current value of the next statement ID counter

MON$REPLICA_MODE

SMALLINT

Database replica mode

0 - not a replica
1 - read-only replica
2 - read-write replica

`MON$IO_STATS`

MON$IO_STATS displays input/output statistics.The counters are cumulative, by group, for each group of statistics.

Column Name Data Type Description

Column Name	Data Type	Description
`MON$STAT_ID`	`INTEGER`	Statistics identifier
`MON$STAT_GROUP`	`SMALLINT`	Statistics group: `0` - database `1` - connection `2` - transaction `3` - statement `4` - call
`MON$PAGE_READS`	`BIGINT`	Count of database pages read
`MON$PAGE_WRITES`	`BIGINT`	Count of database pages written to
`MON$PAGE_FETCHES`	`BIGINT`	Count of database pages fetched
`MON$PAGE_MARKS`	`BIGINT`	Count of database pages marked

MON$STAT_ID

INTEGER

Statistics identifier

MON$STAT_GROUP

SMALLINT

Statistics group:

0 - database
1 - connection
2 - transaction
3 - statement
4 - call

MON$PAGE_READS

BIGINT

Count of database pages read

MON$PAGE_WRITES

BIGINT

Count of database pages written to

MON$PAGE_FETCHES

BIGINT

Count of database pages fetched

MON$PAGE_MARKS

BIGINT

Count of database pages marked

docnext count = 4

`MON$MEMORY_USAGE`

MON$MEMORY_USAGE displays memory usage statistics.

Column Name Data Type Description

Column Name	Data Type	Description
`MON$STAT_ID`	`INTEGER`	Statistics identifier
`MON$STAT_GROUP`	`SMALLINT`	Statistics group: `0` - database `1` - connection `2` - transaction `3` - operator `4` - call
`MON$MEMORY_USED`	`BIGINT`	The amount of memory in use, in bytes.This data is about the high-level memory allocation performed by the server.It can be useful to track down memory leaks and excessive memory usage in connections, procedures, etc.
`MON$MEMORY_ALLOCATED`	`BIGINT`	The amount of memory allocated by the operating system, in bytes.This data is about the low-level memory allocation performed by the Firebird memory manager — the amount of memory allocated by the operating system — which can allow you to control the physical memory usage.
`MON$MAX_MEMORY_USED`	`BIGINT`	The maximum number of bytes used by this object
`MON$MAX_MEMORY_ALLOCATED`	`BIGINT`	The maximum number of bytes allocated for this object by the operating system

MON$STAT_ID

INTEGER

Statistics identifier

MON$STAT_GROUP

SMALLINT

Statistics group:

0 - database
1 - connection
2 - transaction
3 - operator
4 - call

MON$MEMORY_USED

BIGINT

The amount of memory in use, in bytes.This data is about the high-level memory allocation performed by the server.It can be useful to track down memory leaks and excessive memory usage in connections, procedures, etc.

MON$MEMORY_ALLOCATED

BIGINT

The amount of memory allocated by the operating system, in bytes.This data is about the low-level memory allocation performed by the Firebird memory manager — the amount of memory allocated by the operating system — which can allow you to control the physical memory usage.

MON$MAX_MEMORY_USED

BIGINT

The maximum number of bytes used by this object

MON$MAX_MEMORY_ALLOCATED

BIGINT

The maximum number of bytes allocated for this object by the operating system

Note

Counters associated with database-level records MON$DATABASE (MON$STAT_GROUP = 0), display memory allocation for all connections.In the Classic and SuperClassic zero values of the counters indicate that these architectures have no common cache.

Minor memory allocations are not accrued here but are added to the database memory pool instead.

Getting 10 requests consuming the most memory

SELECT
  STMT.MON$ATTACHMENT_ID,
  STMT.MON$SQL_TEXT,
  MEM.MON$MEMORY_USED
FROM MON$MEMORY_USAGE MEM
NATURAL JOIN MON$STATEMENTS STMT
ORDER BY MEM.MON$MEMORY_USED DESC
FETCH FIRST 10 ROWS ONLY

`MON$RECORD_STATS`

MON$RECORD_STATS displays record-level statistics.The counters are cumulative, by group, for each group of statistics.

Column Name Data Type Description

Column Name	Data Type	Description
`MON$STAT_ID`	`INTEGER`	Statistics identifier
`MON$STAT_GROUP`	`SMALLINT`	Statistics group: `0` - database `1` - connection `2` - transaction `3` - statement `4` - call
`MON$RECORD_SEQ_READS`	`BIGINT`	Count of records read sequentially
`MON$RECORD_IDX_READS`	`BIGINT`	Count of records read via an index
`MON$RECORD_INSERTS`	`BIGINT`	Count of inserted records
`MON$RECORD_UPDATES`	`BIGINT`	Count of updated records
`MON$RECORD_DELETES`	`BIGINT`	Count of deleted records
`MON$RECORD_BACKOUTS`	`BIGINT`	Count of records backed out
`MON$RECORD_PURGES`	`BIGINT`	Count of records purged
`MON$RECORD_EXPUNGES`	`BIGINT`	Count of records expunged
`MON$RECORD_LOCKS`	`BIGINT`	Number of records locked
`MON$RECORD_WAITS`	`BIGINT`	Number of update, delete or lock attempts on records owned by other active transactions.Transaction is in `WAIT` mode.
`MON$RECORD_CONFLICTS`	`BIGINT`	Number of unsuccessful update, delete or lock attempts on records owned by other active transactions.These are reported as update conflicts.
`MON$BACKVERSION_READS`	`BIGINT`	Number of back-versions read to find visible records
`MON$FRAGMENT_READS`	`BIGINT`	Number of fragmented records read
`MON$RECORD_RPT_READS`	`BIGINT`	Number of repeated reads of records
`MON$RECORD_IMGC`	`BIGINT`	Number of records processed by the intermediate garbage collector

MON$STAT_ID

INTEGER

Statistics identifier

MON$STAT_GROUP

SMALLINT

Statistics group:

0 - database
1 - connection
2 - transaction
3 - statement
4 - call

MON$RECORD_SEQ_READS

BIGINT

Count of records read sequentially

MON$RECORD_IDX_READS

BIGINT

Count of records read via an index

MON$RECORD_INSERTS

BIGINT

Count of inserted records

MON$RECORD_UPDATES

BIGINT

Count of updated records

MON$RECORD_DELETES

BIGINT

Count of deleted records

MON$RECORD_BACKOUTS

BIGINT

Count of records backed out

MON$RECORD_PURGES

BIGINT

Count of records purged

MON$RECORD_EXPUNGES

BIGINT

Count of records expunged

MON$RECORD_LOCKS

BIGINT

Number of records locked

MON$RECORD_WAITS

BIGINT

Number of update, delete or lock attempts on records owned by other active transactions.Transaction is in WAIT mode.

MON$RECORD_CONFLICTS

BIGINT

Number of unsuccessful update, delete or lock attempts on records owned by other active transactions.These are reported as update conflicts.

MON$BACKVERSION_READS

BIGINT

Number of back-versions read to find visible records

MON$FRAGMENT_READS

BIGINT

Number of fragmented records read

MON$RECORD_RPT_READS

BIGINT

Number of repeated reads of records

MON$RECORD_IMGC

BIGINT

Number of records processed by the intermediate garbage collector

`MON$STATEMENTS`

MON$STATEMENTS displays statements prepared for execution.

Column Name Data Type Description

Column Name	Data Type	Description
`MON$STATEMENT_ID`	`BIGINT`	Statement identifier
`MON$ATTACHMENT_ID`	`BIGINT`	Connection identifier
`MON$TRANSACTION_ID`	`BIGINT`	Transaction identifier
`MON$STATE`	`SMALLINT`	Statement state: `0` - idle `1` - active `2` - stalled
`MON$TIMESTAMP`	`TIMESTAMP WITH TIME ZONE`	The date and time when the statement was prepared
`MON$SQL_TEXT`	`BLOB TEXT`	Statement text in SQL
`MON$STAT_ID`	`INTEGER`	Statistics identifier
`MON$EXPLAINED_PLAN`	`BLOB TEXT`	Explained execution plan
`MON$STATEMENT_TIMEOUT`	`INTEGER`	Connection-level statement timeout in milliseconds.When `0` is reported the timeout of `MON$ATTACHMENT.MON$STATEMENT_TIMEOUT` for this connection applies.
`MON$STATEMENT_TIMER`	`TIMESTAMP WITH TIME ZONE`	Statement timer expiration time
`MON$COMPILED_STATEMENT_ID`	`BIGINT`	Compiled statement id

MON$STATEMENT_ID

BIGINT

Statement identifier

MON$ATTACHMENT_ID

BIGINT

Connection identifier

MON$TRANSACTION_ID

BIGINT

Transaction identifier

MON$STATE

SMALLINT

Statement state:

0 - idle
1 - active
2 - stalled

MON$TIMESTAMP

TIMESTAMP WITH TIME ZONE

The date and time when the statement was prepared

MON$SQL_TEXT

BLOB TEXT

Statement text in SQL

MON$STAT_ID

INTEGER

Statistics identifier

MON$EXPLAINED_PLAN

BLOB TEXT

Explained execution plan

MON$STATEMENT_TIMEOUT

INTEGER

Connection-level statement timeout in milliseconds.When 0 is reported the timeout of MON$ATTACHMENT.MON$STATEMENT_TIMEOUT for this connection applies.

MON$STATEMENT_TIMER

TIMESTAMP WITH TIME ZONE

Statement timer expiration time

MON$COMPILED_STATEMENT_ID

BIGINT

Compiled statement id

The STALLED state indicates that, at the time of the snapshot, the statement had an open cursor and was waiting for the client to resume fetching rows.

Display active queries, excluding those running in your connection

SELECT
  ATT.MON$USER,
  ATT.MON$REMOTE_ADDRESS,
  STMT.MON$SQL_TEXT,
  STMT.MON$TIMESTAMP
FROM MON$ATTACHMENTS ATT
JOIN MON$STATEMENTS STMT ON ATT.MON$ATTACHMENT_ID = STMT.MON$ATTACHMENT_ID
WHERE ATT.MON$ATTACHMENT_ID <> CURRENT_CONNECTION
AND STMT.MON$STATE = 1

Using `MON$STATEMENTS` to Cancel a Query

Monitoring tables are read-only.However, the server has a built-in mechanism for deleting (and only deleting) records in the MON$STATEMENTS table, which makes it possible to cancel a running query.

Note

Notes

If no statements are currently being executed in the connection, any attempt to cancel queries will not proceed
After a query is cancelled, calling execute/fetch API functions will return an error with the isc_cancelled code
Subsequent queries from this connection will proceed as normal
Cancellation of the statement does not occur synchronously, it only marks the request for cancellation, and the cancellation itself is done asynchronously by the server

Example

Cancelling all active queries for the specified connection:

DELETE FROM MON$STATEMENTS
  WHERE MON$ATTACHMENT_ID = 32

MON$DATABASE

MON$DATABASE

MON$IO_STATS

docnext count = 4

MON$MEMORY_USAGE

MON$RECORD_STATS

MON$STATEMENTS

Using MON$STATEMENTS to Cancel a Query

`MON$DATABASE`

`MON$IO_STATS`

`MON$MEMORY_USAGE`

`MON$RECORD_STATS`

`MON$STATEMENTS`

Using `MON$STATEMENTS` to Cancel a Query