Override the now() date/time function used to set the current time in the integer time column in a hypertable. Many policies only apply to chunks of a certain age. integer_now_func determines the age of each chunk.

The function you set as integer_now_func has no arguments. It must be either:

  • IMMUTABLE: Use when you execute the query each time rather than prepare it prior to execution. The value for integer_now_func is computed before the plan is generated. This generates a significantly smaller plan, especially if you have a lot of chunks.

  • STABLE: integer_now_func is evaluated just before query execution starts. chunk pruning is executed at runtime. This generates a correct result, but may increase planning time.

set_integer_now_func does not work on tables where the time column type is TIMESTAMP, TIMESTAMPTZ, or DATE.

main_tableREGCLASSThe hypertable integer_now_func is used in.
integer_now_funcREGPROCA function that returns the current time set in each row in the time column in main_table.
replace_if_existsBOOLEANSet to true to override integer_now_func when you have previously set a custom function. Default is false.

Set the integer now function for a hypertable with a time column in unix time.

  • IMMUTABLE: when you execute the query each time:

    CREATE OR REPLACE FUNCTION unix_now_immutable() returns BIGINT LANGUAGE SQL IMMUTABLE as $$ SELECT extract (epoch from now())::BIGINT $$;
    SELECT set_integer_now_func('hypertable_name', 'unix_now_immutable');
  • STABLE: for prepared statements:

    CREATE OR REPLACE FUNCTION unix_now_stable() returns BIGINT LANGUAGE SQL STABLE AS $$ SELECT extract(epoch from now())::BIGINT $$;
    SELECT set_integer_now_func('hypertable_name', 'unix_now_stable');


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