That will (IMO) not solve the problem, since different threads will be setting and resetting the store format. My suggestion would be to use a pool of connections and each thread work off one connection, and returning it to the pool when done resetting.
-----Original Message----- From: Rahul Raj [mailto:[email protected]] Sent: Wednesday, December 13, 2017 10:23 PM To: [email protected] Subject: Re: Drill session and jdbc connections We are using a one connection and multiple statements for creating the CSV files. I will surround the calls with a finally to reset the store format. Thanks for your inputs, Regards, Rahul On Wed, Dec 13, 2017 at 10:59 PM, Kunal Khatua <[email protected]> wrote: > A Drill session is isolated and bound to a connection. Your > 'getConnection()' method might be fetching connections from a pool, > where the settings haven't been reset. If the connections are shared, > you will continue to have this problem. > > If you are returning a connection back to the pool, run the RESET > command to ensure the default state is set. > > https://urldefense.proofpoint.com/v2/url?u=https-3A__drill.apache.org_ > docs_reset_&d=DwIBaQ&c=cskdkSMqhcnjZxdQVpwTXg&r=-cT6otg6lpT_XkmYy7yg3A > &m=ZvNYB-8v46AopTz4m3cYOACJ-OZevKaxg0jBJBBq2MQ&s=-DeteEKKw3vUytwB7ZEVn > yDMb5mIeceotKszFZsjSjE&e= > > > > -----Original Message----- > From: Rahul Raj [mailto:[email protected]] > Sent: Wednesday, December 13, 2017 2:17 AM > To: [email protected] > Subject: Drill session and jdbc connections > > Hi, > > How is a drill session related to a drill jdbc connection instance? > What happens in a pool of connections when one connection changes the > store.format? I am seeing some mix-ups where a parquet row is written > as an array of multiple records(rather than multiple columns) when > another thread tries to create a csv file. This happens only during > the race condition between CSV and parquet formats. > > Scenario: > > Thread 1 for CSV creation: > > Connection conn = getConnection(); > conn.execute("ALTER SESSION SET `store.format`='csv'") > conn.execute("CREATE TABLE someparquet AS ...") conn.execute("ALTER > SESSION SET `store.format`='parquet'") > > Thread 2 for parquet creation: > > Connection conn = getConnection(); > conn.execute("CREATE TABLE somecsv AS ...") > > In thread 2, the parquet gets written as an ARRAY with all the fields > because of the side effect of Thread 1 setting format as CSV when they > execute in parallel. > > Is it possible to have session isolation in this situation? > > Regards, > Rahul > > -- > **** This email and any files transmitted with it are confidential and > intended solely for the use of the individual or entity to whom it is > addressed. If you are not the named addressee then you should not > disseminate, distribute or copy this e-mail. Please notify the sender > immediately and delete this e-mail from your system.**** > -- **** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom it is addressed. If you are not the named addressee then you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and delete this e-mail from your system.****
