Example:
User JIM likes to run CROSS JOINS on tables with a lot of records which requires a significant amount of RAM. Let’s stop him from doing that!
dbadmin=> CREATE RESOURCE POOL all_users MAXMEMORYSIZE '2G' MAXQUERYMEMORYSIZE '400000K';
CREATE RESOURCE POOL
dbadmin=> ALTER USER jim RESOURCE POOL all_users;
ALTER USER
dbadmin=> \c - jim
You are now connected as user "jim".
dbadmin=> SELECT * FROM big_fact2 a CROSS JOIN big_fact2 b CROSS JOIN big_fact2 c;
ERROR 8722: The minimal memory required by the query [497460 KB] exceeds the query cap size [400000 KB]
HINT: Increase MAXQUERYMEMORYSIZE parameter of the 'all_users' resource pool
Note that he’s still able to run queries that use less memory than the value of MAXQUERYMEMORYSIZE.
dbadmin=> SELECT COUNT(*) FROM big_fact2;
COUNT
-----------
200000000
(1 row)
dbadmin=> SELECT COUNT(*) FROM big_fact2 WHERE c1 = 'AAAAC';
COUNT
-------
15
(1 row)
Helpful Link:https://www.vertica.com/docs/latest/HTML/Content/Authoring/SQLReferenceManual/Statements/Built-inPoolConfiguration.htm
Have fun!
About the Author
James Knicely
Vertica Field Chief Technologist
I've had the privilege of working with many database technologies in my career. But after being introduced to Vertica in May of 2011 as a client, I was hooked on the new technology after witnessing a query run in milliseconds that had previously ran for hours on the legacy database we had in place. It was then that I knew I wanted to eventually join the Vertica team, and 4 years later I did! I am currently a Vertica evangelist and am ready to help you get on board! Please feel free to reach out to me with any questions you have about Vertica and make sure to follow my Vertica Quick Tips!
