ttSize

Estimates the amount of space that a given table, including any views in the database, will consume when the table grows to include rows. You can use this utility on existing tables or to estimate table sizes when creating tables. If you do not specify an owner, ttSize prints size information for all tables of the given table name. The size information includes space occupied by any indexes defined on the table.

The memory required for varying-length columns is estimated by using the average length of the columns in the current table as the average length of the columns in the final table. If there are no rows in the current table, then ttSize assumes that the average column length is one half the maximum column length.

The memory required for LOB columns is estimated by using the average length of the columns in the current table as the average length of the columns in the final table. When no rows are being inserted into the table, computations do not include LOB columns.

The table is scanned when this utility is called. Avoid the scan of the table by specifying an optional non-NULL frac value, which should be between 0 and 1. The ttSize utility uses this value to estimate the average size of varying-length columns. The maximum size of each varying-length column is multiplied by the frac value to compute the estimated average size of VARBINARY or VARCHAR columns. If the frac option is not specified, the existing rows in the table are scanned and the average length of the varying-length columns in the existing rows is used. If frac is not specified and the table has no rows in it, then frac is assumed to have the value 0.5.

Required Privilege

This utility requires no privileges beyond those needed to perform select operations on the specified database objects.

Usage in TimesTen Scaleout and TimesTen Classic

This utility is supported in both TimesTen Classic and TimesTen Scaleout.

Syntax

ttSize {-h | -help | -?}
ttSize {-V | -version}
ttSize -tbl [owner.][tableName] [-rows rows] [- frac fraction] 
     {-connStr connection_string | DSN}

Options

ttSize has the options:

Option	Description
-connStr connection_string	An ODBC connection string that specifies a database location, driver, and optionally other connection attribute settings.
DSN	Specifies the name of a data source to which ttSize should connect to retrieve table information.
-frac frac	Specifies the estimated average fraction of out-of-line VARCHAR or VARBINARY column sizes that will be used. If this option is omitted and the table contains out-of-line variable sized columns, a table scan is done to determine the average sizes. If the table is empty, the fraction is estimated to be 0.5 (50%) filled.
-h -help -?	Prints a usage message and exits.
-tbl [owner.][tableName]	Specifies the name of the table whose definition should be used for size estimation. If the owner is omitted, the login name of the user is tried. If that is not found, the user SYS is used. tableName is an optional parameter. The output of ttSize is not very useful if you omit the tableName parameter.
-rows rows	Specifies the expected number of rows in the table. Space required to store a TimesTen table includes space for the actual data, plus overhead for bookkeeping, dynamic memory allocation and indexes. TimesTen may consume additional space due to memory fragmentation, temporary space allocated during query implementation and space to hold compiled SQL statements. If this option is omitted, the ttSize utility uses the number of rows in the existing table to estimate the table space, or uses 1 row if the table is empty.
-V | -version	Prints the release number of ttSize and exits.

Examples

To estimate the space required for a table, create the table in TimesTen, populate it with a sample of representative rows, create desired indexes and runttSize with those definitions. For example, to estimate the size of the NAMEID table in the data source FixedDs when it grows to 200,000 rows, run:

% ttSize -tbl Nameid -rows 200000 FixedDs

Rows = 200000

Total in-line row bytes = 7139428

Total = 7139428

Notes

• LOB columns are treated similar to var-type columns, unless there are no rows being inserted into the table. The average size computation does not include LOB columns in such cases.

• The columns PERM_ALLOCATED_SIZE and PERM_IN_USE_SIZE show the currently allocated size of the database (in KB units) and the in-use size of the database. The system updates this information each time a connection is made or released and each time a transaction is committed or rolled back.

• This utility is supported only for TimesTen Data Manager DSNs and not for TimesTen Client DSNs.