das_batch_rpc_delay_us

Overview

das_batch_rpc_delay_us controls the aggregated sending delay for the global index back-to-table batch RPC channel (LOOKUP_DAS_BATCH_REQ1/2).

Privilege requirements

• Query parameters \

  Both the sys tenant and all user tenants can query this parameter using the SHOW PARAMETERS statement or the GV$OB_PARAMETERS view.

• Modify parameters.

  Only the sys tenant can modify this parameter. User tenants cannot modify it.

Attributes

Usage instructions

The parameter das_batch_rpc_delay_us applies only to the LOOKUP_DAS_BATCH_REQ1/2 batch type and does not affect the latency of other batch channels such as CLOG_BATCH_REQ.

A larger aggregation delay allows more requests to be aggregated per RPC, but results in longer wait times for individual requests. Setting it to 0 means almost no aggregation is performed, and requests are sent immediately.

The following limitations apply to setting the aggregation delay (das_batch_rpc_delay_us):

• This parameter is effective only for tenants with the channel enabled (_enable_das_batch_rpc = 1). When the channel is disabled (_enable_das_batch_rpc = 0), the das_batch_rpc_delay_us parameter is invalid but retained.
• The upper limit of das_batch_rpc_delay_us, which is 1,000,000 μs (1 s), is a protective value. Normal tuning should not approach this limit, as doing so will significantly amplify the wait time for a single lookup.

Configuration example

• Adjusted to 200 μs to improve the degree of aggregation.

  obclient> ALTER SYSTEM SET das_batch_rpc_delay_us = 200;
  

• Restore the default value of 100 μs.

  obclient> ALTER SYSTEM SET das_batch_rpc_delay_us = 100;