NPGTHRSH—NPAGE threshold
Use the Modify NPAGE Threshold panel or the NPGTHRSH command to specify the tables for which Db2 favors matching index access.
The NPGTHRSH parameter lets you specify that Db2 uses special access path selection for tables under a given size. In this situation, you should run RUNSTATS again after the table is populated. Otherwise, you can use the NPGTHRSH parameter to cause Db2 to favor matching index access over a table space scan and over nonmatching index access.
Modify NPAGE Threshold panel
Command ===> _________________________________________________________________
Command: CURRENT
Description . . . . . . . . : NPAGE THRESHOLD
Type the new NPAGE Threshold Value you wish to change to. Then Press Enter.
NPAGE Threshold
NPAGE Threshold . . . . . (ALL, COST, 1 to 2147483647 or delta)
Command syntax and parameters
Value | Description |
|---|---|
DB2ssid | Db2 subsystem ID or the name of the Db2 data sharing group to which the command applies. |
opertuneID | OPERTUNE system profile name (if OPERTUNE is running as a started task) or the batch job name (if OPERTUNE is running as a batch job). |
COST | Db2 selects the access path based on cost, and no tables qualify for special handling This is the default. |
ALL | Db2 favors matching index access for all tables. |
value | NPAGES threshold value. Specify one of the following values:
If data access statistics have been collected for all tables, and the total number of pages on which rows of the table appear (NPAGES) is less than this value, Db2 favors matching index access. If data access statistics have not been collected for some tables (NPAGES=ALL), Db2 favors matching index access for tables where NPAGES=ALL or is less than this value. |
NORESET | The changes you request remain in effect until the Db2 subsystem is cycled. |
Db2 parameter values
Field | Installation panel | CLIST parameter | ZPARM macro | ZPARM parameter |
|---|---|---|---|---|
NPAGE Threshold | None | None | DSN6SPRM | NPGTHRSH |