Error: F_JG21CF: Internal Error: Read From Temp Store With Illegal Request Size 0

Issue

Integrate with /Burst method fails with the following error:

F_JG21CF: Internal error: read from temp store with illegal request size 0.

Environment

• HVR versions 5.7.5/40 or lower
• Target: All relational database management systems (RDBMS)

Resolution

There are two ways to resolve this issue:

1. Upgrade HVR to version 5.7.5/41 or higher
2. Add the Environment action with the following parameters:
   • Name: HVR_BURST_KEY_RANGE_KEYS
   • Value: 0

HVR_BURST_KEY_RANGE_KEYS environment variable

The HVR_BURST_KEY_RANGE_KEYS environment variable represents the maximum number of key columns HVR can use for range restrictions during set-wise statements. The default value is 5, and the minimum is -1. See the HVR_BURST_KEY_RANGE_KEYS values and their descriptions below:

• -1: All key columns except those with unsuitable values are used.
• 0: Key range calculation is disabled.
• N: The first 4*N key columns are calculated. Only N key columns with suitable ranges are used.

The pipeline calculates the minimum and maximum values of key columns. Set-wise statements refer to these ranges in WHERE clauses, meaning the planner is aware of them before joining.

Some values are unsafe to specify. For example, values that are null, missing, too small, too large, or contain uncertain collation rules, may result in more keys being calculated than needed. A value that is too low risks not having functional restrictions. However, a value that is too high risks overwhelming the DBMS query planner through high CPU usage.

Cause

This issue occurs when one of the key columns doesn't meet the requirements for key range calculation.