2017-06-01 19:55:41 UTC
Now that I have Drill working with parquet files on dfs, the next step was
to move the parquet files to S3.
I get pretty good performance - I can query for events by date range
within 10 seconds. ( out of a total of ~ 800M events across 25 years)
However, there seems to be some threshold beyond which queries start
SYSTEM ERROR: ConnectionPoolTimeoutException: Timeout waiting for
connection from pool
My first question is, is there a default timeout value to queries against
S3? Anything that takes longer than ~ 150 seconds seems to hit the timeout
The second question has to do with the possible conditions that trigger the
prolonged query time. It seems that if I increase the filters beyond a
certain number - it doesn't take much - the query times out.
For example the query:
select * from events where YEAR in (2012, 2013) works fine - however,
select * from events where YEAR in (2012, 2013, 2014) fails with a timeout.
To make it worse, I can't use the first query either until I restart