The SYSCS_DIAG.SPACE_TABLE diagnostic table function shows the space usage of a particular table and its indexes. You can use this diagnostic table function to determine if space might be saved by compressing the table and indexes.
All users can access this diagnostic table function, whether or not the database has authentication and SQL authorization enabled.
The returned table has the columns shown in the following table.
Column Name | Type | Length | Nullable | Contents |
---|---|---|---|---|
CONGLOMERATENAME | VARCHAR | 128 | true | The name of the conglomerate, which is either the table name or the index name. (Unlike the SYSCONGLOMERATES column of the same name, table ID's do not appear here). |
ISINDEX | SMALLINT | 5 | false | Is not zero if the conglomerate is an index, 0 otherwise. |
NUMALLOCATEDPAGES | BIGINT | 20 | false | The number of pages actively linked into the table. The total number of pages in the file is the sum of NUMALLOCATEDPAGES + NUMFREEPAGES. |
NUMFREEPAGES | BIGINT | 20 | false | The number of free pages that belong to the table. When a new page is to be linked into the table the system will move a page from the NUMFREEPAGES list to the NUMALLOCATEDPAGES list. The total number of pages in the file is the sum of NUMALLOCATEDPAGES + NUMFREEPAGES. |
NUMUNFILLEDPAGES | BIGINT | 20 | false | The number of unfilled pages that belong to the table. Unfilled pages are allocated pages that are not completely full. Note that the number of unfilled pages is an estimate and is not exact. Running the same query twice can give different results on this column. |
PAGESIZE | INTEGER | 10 | false | The size of the page in bytes for that conglomerate. |
ESTIMSPACESAVING | BIGINT | 20 | false | The estimated space which could possibly be saved by compressing the conglomerate, in bytes. |
TABLEID | CHAR | 36 | false | The id of the table to which the conglomerate belongs. |
SELECT sysschemas.schemaname, T2.* FROM SYS.SYSTABLES systabs, SYS.SYSSCHEMAS sysschemas, TABLE (SYSCS_DIAG.SPACE_TABLE()) AS T2 WHERE systabs.tabletype = 'T' AND sysschemas.schemaid = systabs.schemaid AND systabs.tableid = T2.tableid;where T2 is a user-specified table name that is any valid identifier.
Both the schemaName and the tableName arguments must be expressions whose data types map to Java strings. If the schemaName and the tableName are non-delimited identifiers, you must specify the names in upper case.
SELECT * FROM TABLE (SYSCS_DIAG.SPACE_TABLE('MYSCHEMA', 'MYTABLE')) AS T2