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.. index:: database

Custom Time-Date Functions

The present Socorro database needs to do a lot of time, date and timezone manipulation. This is partly a natural consequence of the application, and the need to use both DATE and TIMESTAMPTZ values. The greater need is legacy timestamp, conversion, however; currently the processors save crash reporting timestamps as TIMESTAMP WITHOUT TIMEZONE in Pacific time, whereas the rest of the database is TIMESTAMP WITH TIME ZONE in UTC. This necessitates a lot of tricky time zone conversions.

The functions below are meant to make it easier to write queries which return correct results based on dates and timestamps.

tstz_between

tstz_between (
        tstz TIMESTAMPTZ,
        bdate DATE,
        fdate DATE
)
RETURNS BOOLEAN

SELECT tstz_between ( '2011-11-25 15:23:11-08',
        '2011-11-25', '2011-11-26' );

Checks whether a timestamp with time zone is between two UTC dates, inclusive of the entire ending day.

utc_day_is

utc_day_is (
        TIMESTAMPTZ,
        TIMESTAMP or DATE
        )
RETURNS BOOLEAN

SELECT utc_day_is ( '2011-11-26 15:23:11-08', '2011-11-28' );

Checks whether the provided timestamp with time zone is within the provided UTC day, expressed as either a timestamp without time zone or a date.

utc_day_near

utc_day_near (
        TIMESTAMPTZ,
        TIMESTAMP or DATE
        )
RETURNS BOOLEAN

SELECT utc_day_near ( '2011-11-26 15:23:11-08', '2011-11-28' );

Checks whether the provided timestamp with time zone is within an hour of the provided UTC day, expressed as either a timestamp without time zone or a date. Used for matching when related records may cross over midnight.

week_begins_utc

week_begins_utc (
        TIMESTAMP or DATE
        )
RETURNS timestamptz

SELECT week_begins_utc ( '2011-11-25' );

Given a timestamp or date, returns the timestamp with time zone corresponding to the beginning of the week in UTC time. Used for partitioning data by week.

week_ends_utc

week_ends_utc (
        TIMESTAMP or DATE
        )
RETURNS timestamptz

SELECT week_ends_utc ( '2011-11-25' );

Given a timestamp or date, returns the timestamp with time zone corresponding to the end of the week in UTC time. Used for partitioning data by week.

week_begins_partition

week_begins_partition (
        partname TEXT
        )
RETURNS timestamptz

SELECT week_begins_partition ( 'reports_20111219' );

Given a partition table name, returns a timestamptz of the date and time that weekly partition starts.

week_ends_partition

week_ends_partition (
        partname TEXT
        )
RETURNS timestamptz

SELECT week_ends_partition ( 'reports_20111219' );

Given a partition table name, returns a timestamptz of the date and time that weekly partition ends.

week_begins_partition_string

week_begins_partition_string (
        partname TEXT
        )
RETURNS text

SELECT week_begins_partition_string ( 'reports_20111219' );

Given a partition table name, returns a string of the date and time that weekly partition starts in the format 'YYYY-MM-DD HR:MI:SS UTC'.

week_ends_partition_string

week_ends_partition_string (
        partname TEXT
        )
RETURNS text

SELECT week_ends_partition_string ( 'reports_20111219' );

Given a partition table name, returns a string of the date and time that weekly partition ends in the format 'YYYY-MM-DD HR:MI:SS UTC'.