Query Execution Polling

When a query is run, the connector polls the Athena server for the query results until they are returned. The connector starts by polling the server frequently, and then increasing the interval of time between polls (decreasing the polling rate) as the query continues to run. You can configure the polling rate of the connector by setting the following properties:

• MinQueryExecutionPollingInterval
• MaxQueryExecutionPollingInterval
• QueryExecutionPollingIntervalMultiplier

The connector starts by polling the server every minimum interval, which is the number of milliseconds specified in MinQueryExecutionPollingInterval. The connector then increases the polling interval using the multiplier specified in QueryExecutionPollingIntervalMultiplier until the interval specified in MaxQueryExecutionPollingInterval is reached. The connector then continues to poll the server using this maximum interval until the query results are returned.

For example, the connector uses the following default settings for query execution polling:

• MinQueryExecutionPollingInterval=5
• MaxQueryExecutionPollingInterval=1800000
• QueryExecutionPollingIntervalMultiplier=2

Using these settings, the connector polls the server 5ms after the query begins to run, and then doubles the interval between polls after each subsequent poll. In other words, the connector polls the server at these intervals: 5ms after the query starts to run, 10ms after the first poll, 20ms after the second poll, and so on until the 1800000ms polling interval is reached. The connector then continues to poll the server every 1800000ms until the query results are returned.