ttOptSetColIntvlStats

Description

Modifies the statistics for the specified columns with interval information. This procedure allows an application to set statistics manually rather than have TimesTen automatically compute them. This feature is useful for preparing commands before the data has been inserted or for seeing how table characteristics can affect the choice of execution plan. This procedure modifies the relevant row(s) in the COL_STATS system table.

Because this procedure can be used before any data are in the table, the values specified do not need to bear any relation to the actual values, although some basic validity checking is performed.

Required privilege

This procedure requires no privilege (if owner) or ALTER ANY TABLE privilege (if not owner).

Syntax

ttOptSetColIntvlStats('tblName', 'colName', invalidate, (stats))

Parameters

ttOptSetColIntvlStats has these parameters:

Parameter	Type	Description
`tblName`	TT_CHAR(61) NOT NULL	Name of an application table. Can include table owner.
`colName`	TT_CHAR(30) NOT NULL	Name of a column in that table.
`invalidate`	TT_INTEGER	0 (no) or 1 (yes). If `invalidate` is 1, all commands that reference the affected tables are automatically prepared again when re-executed. This includes commands prepared by other users. If `invalidate` is 0, the statistics are not considered to have been modified and existing commands are not reprepared.
stats	VARBINARY (409600) NOT NULL	Sets stats for the column, using the format: `(numInterval integer, numNull integer, totUniq integer, totTups integer,` `/* information for interval 1 /` `(numUniq integer, numTups integer, frequency of most occurred value integer, minVal, maxVal, modVal),` `/ information for interval 2 */...)`

Result set

ttOptSetColIntvlStats returns no results.

Example

To set the following statistics for column t1.x1:

Two intervals
Integer type
10 rows with null value
10 unique value
100 rows
Interval 1 (4 unique values besides the most frequently occurring value, 40 rows with values other than most frequently occurring value, 10 rows with most frequently occurring value, min = 1, max = 10, mod = 5)
Interval 2 (4 unique values besides the most frequently occurring value, 20 rows with values other than most frequently occurring, 20 rows with most frequently occurring value, min = 11, max = 20, mod = 15)

Use the statement:

CALLttOptSetColIntvlStats('t1', 'x1', 1, (2, 10, 10, 100, (4, 40, 10, 1, 10, 5), (4, 20, 20, 11, 20, 15)));

Notes

The minimum and maximum values in the interval need to be given as VARBINARY. NULL values are not permitted as minimum or maximum values. The value is stored in the platform-specific endian format.