PN_STAGEBLOB_THRESHOLD configuration parameter

Use the PN_STAGEBLOB_THRESHOLD configuration parameter to reserve space for BYTE and TEXT data in round-robin fragments.

onconfig.std value
Not set.
if not present
0
values
0 - 1000000
units
Kilobytes
takes effect
After you edit your onconfig file and restart the database server.
When you reset the value dynamically in your onconfig file by running the onmode -wf command.
When you reset the value in memory by running the onmode -wm command.

Usage

Set this configuration parameter to the typical or average size of the BYTE or TEXT data that is stored in the table.

Restriction: The PN_STAGEBLOB_THRESHOLD configuration parameter has no effect if the number of extents has reached the maximum extents allowed or if the dbspace is full.

When a table reaches the maximum number of pages for a fragment, more pages can be added to the table by adding a new fragment. However, if a table contains BYTE or TEXT columns and that table is fragmented by the round-robin distribution scheme, adding a new fragment does not automatically enable new rows to be inserted into the new fragment.

For example, if one of the fragments in the table reaches the maximum number of pages, adding a new fragment does not extend the table to store more rows. Because BYTE and TEXT data tend to be large in size, the data is staged in one of the fragments before being distributed evenly in all of the fragments. The staging fragment must have sufficient space to store the BYTE or TEXT data. Use the PN_STAGEBLOB_THRESHOLD configuration parameter so that the database server can stage the BYTE or TEXT data temporarily in a staging fragment until the INSERT operation is completed and the data is permanently stored in the table.

During a UPDATE operation if the fragment does not have the space that is specified in PN_STAGEBLOB_THRESHOLD configuration parameter the table row that is impacted by the updated is moved into another fragment.


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