This documentation is related to an older version of Firebolt. For the most current documentation, see Firebolt documentation.

Firebolt system settings

You can use a SET statement in a SQL script to configure aspects of Firebolt system behavior. Each statement is a query in its own right and must be terminated with a semi-colon (;). The SET statement cannot be included in other queries. This topic provides a list of available settings by function.

Set time zone

Use this setting to specify the session time zone. Time zone names are from the tz database (see the list of tz database time zones). The default value of the time_zone setting is UTC. For times in the future, the latest known rule for the given time zone is applied. Firebolt does not support time zone abbreviations, as they cannot account for daylight savings time transitions, and some time zone abbreviations meant different UTC offsets at different times.

Syntax

SET time_zone = '<time_zone>'

Example

SET time_zone = 'UTC';
SELECT TIMESTAMPTZ '1996-09-03 11:19:33.123456 Europe/Berlin';  --> 1996-09-03 09:19:33.123456+00
SELECT TIMESTAMPTZ '2023-1-29 6:3:42.7-3:30';  --> 2023-01-29 09:33:42.7+00

SET time_zone = 'Israel';
SELECT TIMESTAMPTZ '2023-1-29 12:21:49';  --> 2023-01-29 12:21:49+02
SELECT TIMESTAMPTZ '2023-1-29Z';  --> 2023-01-29 02:00:00+02

Enable parsing for literal strings

When set to true, strings are parsed without escaping, treating backslashes literally. By default this is disabled, and the \ character is recognized as an escape character.

Syntax

SET standard_conforming_strings = [false|true]

Example

SET standard_conforming_strings = false;
SELECT '\x3132'; -> 132

SET standard_conforming_strings = true;
SELECT '\x3132'; -> \x3132

Enable exact COUNT (DISTINCT)

When set to false (0), the COUNT (DISTINCT) function returns approximate results, using an estimation algorithm with an average deviation under 2%. This is the default to optimize query performance. When set to true (1), the function returns an exact count, which can slow query performance.

This function can be used in Aggregating Indexes. When asking Support to permanently change the setting, it will be necessary to drop and recreate any aggregating indexes that use the the COUNT(DISTINCT) aggregation after the change is made. That will allow the aggregation values to be calculated with the new setting.

Syntax

firebolt_optimization_enable_exact_count_distinct = [false|true]

Example

SET firebolt_optimization_enable_exact_count_distinct = true;

Limit the number of result rows

When set to a value greater than zero, this setting limits the number of rows returned by SELECT statements. The query is executed as if an additional LIMIT clause is added to the SQL query. The default value is zero.

Syntax

SET max_result_rows = <integer>;

Example

SET max_result_rows = 10000;
SELECT * FROM table;

is equivalent to

SELECT * FROM table LIMIT 10000;