ttSize

Description

Estimates the amount of space that a given table, including any views in the data store will consume when it grows to include rows rows. It can be used on existing tables or to estimate table sizes when creating tables. If no owner is specified, the size information is printed for all tables of the given 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 table is scanned when this utility is called. The scan of the table can be avoided by specifying an optional non-NULL frac value, which should be between 0 and 1. This value is used 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 data store objects.

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 containing the name of the data store, the server name and DSN (if necessary) and any relevant connection attributes.
`DSN`	Specifies the name of a data source to which ttSize should connect to retrieve table information.
`-frac` `fraction`	Estimated average fraction of VARBINARY or VARCHAR column sizes.
`-h` `-help` `-?`	Prints a usage message and exits.
`-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 execution and space to hold compiled SQL statements. If this option is omitted, the number of rows in the existing table is used, or 1 if the table is empty.
`-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.
`-V \| -version`	Prints the release number of ttSize and exits.

Example

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 execute ttSize 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, execute:

ttSize FixedDs -tbl Nameid -rows 200000

Notes

Another method for estimating size requirements and measuring fragmentation is to use the MONITOR table. (See "SYS.MONITOR" in Oracle TimesTen In-Memory Database SQL Reference.)

The columns PERM_ALLOCATED_SIZE and PERM_IN_USE_SIZE show the currently allocated size of the data store (in KB units) and the in-use size of the data store. 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. It is not supported for TimesTen Client DSNs.