timescaledb/sql/util_internal_table_ddl.sql

-- This file contains functions associated with creating new
-- hypertables.

-- Creates a new schema if it does not exist.
CREATE OR REPLACE FUNCTION _timescaledb_internal.create_schema(
    schema_name NAME
)
    RETURNS VOID LANGUAGE PLPGSQL VOLATILE AS
$BODY$
BEGIN
    EXECUTE format(
        $$
            CREATE SCHEMA IF NOT EXISTS %I
        $$, schema_name);
END
$BODY$
SET client_min_messages = WARNING -- suppress NOTICE on IF EXISTS
;

CREATE OR REPLACE FUNCTION _timescaledb_internal.chunk_create_table(
    chunk_id INT,
    tablespace_name NAME
)
    RETURNS VOID LANGUAGE PLPGSQL VOLATILE AS
$BODY$
DECLARE
    chunk_row _timescaledb_catalog.chunk;
    hypertable_row _timescaledb_catalog.hypertable;
    tablespace_clause TEXT := '';
    table_owner     NAME;
    tablespace_oid  OID;
BEGIN
    SELECT * INTO STRICT chunk_row
    FROM _timescaledb_catalog.chunk
    WHERE id = chunk_id;

    SELECT * INTO STRICT hypertable_row
    FROM _timescaledb_catalog.hypertable
    WHERE id = chunk_row.hypertable_id;

    SELECT t.oid
    INTO tablespace_oid
    FROM pg_catalog.pg_tablespace t
    WHERE t.spcname = tablespace_name;

    SELECT tableowner
    INTO STRICT table_owner
    FROM pg_catalog.pg_tables
    WHERE schemaname = hypertable_row.schema_name
          AND tablename = hypertable_row.table_name;

    IF tablespace_oid IS NOT NULL THEN
        tablespace_clause := format('TABLESPACE %s', tablespace_name);
    ELSIF tablespace_name IS NOT NULL THEN
        RAISE EXCEPTION 'No tablespace % in database %', tablespace_name, current_database()
        USING ERRCODE = 'IO501';
    END IF;

    EXECUTE format(
        $$
            CREATE TABLE IF NOT EXISTS %1$I.%2$I () INHERITS(%3$I.%4$I) %5$s;
        $$,
        chunk_row.schema_name, chunk_row.table_name,
        hypertable_row.schema_name, hypertable_row.table_name, tablespace_clause
    );

    EXECUTE format(
        $$
            ALTER TABLE %1$I.%2$I OWNER TO %3$I
        $$,
        chunk_row.schema_name, chunk_row.table_name,
        table_owner
    );
END
$BODY$;

CREATE OR REPLACE FUNCTION _timescaledb_internal.dimension_slice_get_constraint_sql(
    dimension_slice_id  INTEGER
)
    RETURNS TEXT LANGUAGE PLPGSQL VOLATILE AS
$BODY$
DECLARE
    dimension_slice_row _timescaledb_catalog.dimension_slice;
    dimension_row _timescaledb_catalog.dimension;
    proargtype  OID;
    typecast TEXT = '';
BEGIN
    SELECT * INTO STRICT dimension_slice_row
    FROM _timescaledb_catalog.dimension_slice
    WHERE id = dimension_slice_id;

    SELECT * INTO STRICT dimension_row
    FROM _timescaledb_catalog.dimension
    WHERE id = dimension_slice_row.dimension_id;

    IF dimension_row.partitioning_func IS NOT NULL THEN
        SELECT proargtypes[0] INTO STRICT proargtype
        FROM pg_proc p, pg_namespace n
        WHERE n.nspname = dimension_row.partitioning_func_schema
        AND p.proname = dimension_row.partitioning_func
        AND n.oid = p.pronamespace;

        -- Check if we are using a legacy partitioning function
        -- that only takes text input
        IF proargtype = 'text'::regtype THEN
            typecast := '::text';
        END IF;

        return format(
            $$
                %1$I.%2$s(%3$I%4$s) >= %5$L AND %1$I.%2$s(%3$I%4$s) < %6$L
            $$,
            dimension_row.partitioning_func_schema,
            dimension_row.partitioning_func,
            dimension_row.column_name,
            typecast,
            dimension_slice_row.range_start,
            dimension_slice_row.range_end);
    ELSE
        --TODO: only works with time for now
        IF _timescaledb_internal.time_literal_sql(dimension_slice_row.range_start, dimension_row.column_type) =
           _timescaledb_internal.time_literal_sql(dimension_slice_row.range_end, dimension_row.column_type) THEN
            RAISE 'Time based constraints have the same start and end values for column "%": %',
                    dimension_row.column_name,
                    _timescaledb_internal.time_literal_sql(dimension_slice_row.range_end, dimension_row.column_type);
        END IF;
        return format(
            $$
                %1$I >= %2$s AND %1$I < %3$s
            $$,
            dimension_row.column_name,
            _timescaledb_internal.time_literal_sql(dimension_slice_row.range_start, dimension_row.column_type),
            _timescaledb_internal.time_literal_sql(dimension_slice_row.range_end, dimension_row.column_type));
    END IF;
END
$BODY$;

-- Outputs the create_hypertable command to recreate the given hypertable.
--
-- This is currently used internally for our single hypertable backup tool
-- so that it knows how to restore the hypertable without user intervention.
--
-- It only works for hypertables with up to 2 dimensions.
CREATE OR REPLACE FUNCTION _timescaledb_internal.get_create_command(
    table_name NAME
)
    RETURNS TEXT LANGUAGE PLPGSQL VOLATILE AS
$BODY$
DECLARE
    h_id             INTEGER;
    schema_name      NAME;
    time_column      NAME;
    time_interval    BIGINT;
    space_column     NAME;
    space_partitions INTEGER;
    dimension_cnt    INTEGER;
    dimension_row    record;
    ret              TEXT;
BEGIN
    SELECT h.id, h.schema_name
    FROM _timescaledb_catalog.hypertable AS h
    WHERE h.table_name = get_create_command.table_name
    INTO h_id, schema_name;

    IF h_id IS NULL THEN
        RAISE EXCEPTION 'hypertable % not found', table_name
        USING ERRCODE = 'IO101';
    END IF;

    SELECT COUNT(*)
    FROM _timescaledb_catalog.dimension d
    WHERE d.hypertable_id = h_id
    INTO STRICT dimension_cnt;

    IF dimension_cnt > 2 THEN
        RAISE EXCEPTION 'get_create_command only supports hypertables with up to 2 dimensions'
        USING ERRCODE = 'IO101';
    END IF;

    FOR dimension_row IN
        SELECT *
        FROM _timescaledb_catalog.dimension d
        WHERE d.hypertable_id = h_id
        LOOP
        IF dimension_row.interval_length IS NOT NULL THEN
            time_column := dimension_row.column_name;
            time_interval := dimension_row.interval_length;
        ELSIF dimension_row.num_slices IS NOT NULL THEN
            space_column := dimension_row.column_name;
            space_partitions := dimension_row.num_slices;
        END IF;
    END LOOP;

    ret := format($$SELECT create_hypertable('%I.%I', '%I'$$, schema_name, table_name, time_column);
    IF space_column IS NOT NULL THEN
        ret := ret || format($$, '%I', %s$$, space_column, space_partitions);
    END IF;
    ret := ret || format($$, chunk_time_interval => %s, create_default_indexes=>FALSE);$$, time_interval);

    RETURN ret;
END
$BODY$;