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SQL Query Size Limit?

Posted: Fri Jan 08, 2016 2:38 pm
by billykopecki
Howdy,

Anyone know if there is a limit on the size of a query that can be executed in Vertica? If so, what is the limit?

I may have to write a query with a bunch of unions and am curious how many I can string together...

Thanks in advance!

Re: SQL Query Size Limit?

Posted: Fri Jan 08, 2016 4:35 pm
by JimKnicely
Hi,

As far as I know, there is no explicit limit defined in Vertica for the length (number of characters) of a SQL query.

There is a DB parameter that limits the max memory allowed for parsing:

Code: Select all

dbadmin=> select default_value, description from configuration_parameters where parameter_name = 'MaxParsedQuerySizeMB';
 default_value |                                                              description
---------------+---------------------------------------------------------------------------------------------------------------------------------------
 512           | Maximum amount of memory allowed for parsing a single request; Increasing this value may help with 'Request size too big' errors (MB)
(1 row)
Keep in mind the larger the query the worse they will perform. So I wouldn't mess with that parameter and I would try to keep the query sizes manageable.

Thanks!