[DRILL-5016] Config param drill.exec.sort.purge.threshold is misnamed

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 1.8.0
• Assignee: Unassigned
• Reporter: Paul Rogers
• Created: 08/Nov/16 19:05
• Updated: 19/Jun/17 18:43

Description

The Drill config system provides a property called drill.exec.sort.purge.threshold. The name suggests that this is a parameter related to sorting. Perhaps it controls something having to do with when we purge buffered batches from memory in the ExternalSortBatch?

In fact, this is actually drill.exec.topn.purge-threshold - it affects only the Top-N operator, not sort.

To make this change, rename the config attribute in ExecConstants from

  String BATCH_PURGE_THRESHOLD = "drill.exec.sort.purge.threshold";

to:

  String TOP_N_PURGE_THRESHOLD = "drill.exec.topn.purge-threshold";

To permit backward compatibility, modify the use in TopNBatch to check the old value, use it if set, else use the new value.

    // Check pre x.y config parameter for backward compatibility.

    if ( ! context.getConfig( ).isEmpty( "drill.exec.sort.purge.threshold" ) ) {
      batchPurgeThreshold = context.getConfig().getInt("drill.exec.sort.purge.threshold");
    } else {
      batchPurgeThreshold = context.getConfig().getInt(ExecConstants. TOP_N_PURGE_THRESHOLD);
    }