-- Fix bug causing never-ending loop while calculating partition range for natively partitioned tables. Github issue #273

CREATE OR REPLACE FUNCTION @extschema@.partition_data_time(
        p_parent_table text
        , p_batch_count int DEFAULT 1
        , p_batch_interval interval DEFAULT NULL
        , p_lock_wait numeric DEFAULT 0
        , p_order text DEFAULT 'ASC'
        , p_analyze boolean DEFAULT true
        , p_source_table text DEFAULT NULL)
    RETURNS bigint
    LANGUAGE plpgsql
    AS $$
DECLARE

v_control                   text;
v_control_type              text;
v_datetime_string           text;
v_current_partition_name    text;
v_default_exists            boolean;
v_default_schemaname        text;
v_default_tablename         text;
v_epoch                     text;
v_last_partition            text;
v_lock_iter                 int := 1;
v_lock_obtained             boolean := FALSE;
v_max_partition_timestamp   timestamptz;
v_min_partition_timestamp   timestamptz;
v_new_search_path           text := '@extschema@,pg_temp';
v_old_search_path           text;
v_parent_tablename          text;
v_parent_tablename_real     text;
v_partition_expression      text;
v_partition_interval        interval;
v_partition_suffix          text;
v_partition_timestamp       timestamptz[];
v_partition_type            text;
v_source_schemaname         text;
v_source_tablename          text;
v_rowcount                  bigint;
v_sql                       text;
v_start_control             timestamptz;
v_total_rows                bigint := 0;

BEGIN
/*
 * Populate the child table(s) of a time-based partition set with old data from the original parent
 */

SELECT partition_type
    , partition_interval::interval
    , control
    , datetime_string
    , epoch
INTO v_partition_type
    , v_partition_interval
    , v_control
    , v_datetime_string
    , v_epoch
FROM @extschema@.part_config
WHERE parent_table = p_parent_table;
IF NOT FOUND THEN
    RAISE EXCEPTION 'ERROR: No entry in part_config found for given table:  %', p_parent_table;
END IF;

SELECT schemaname, tablename INTO v_source_schemaname, v_source_tablename
FROM pg_catalog.pg_tables
WHERE schemaname = split_part(p_parent_table, '.', 1)::name
AND tablename = split_part(p_parent_table, '.', 2)::name;

-- Preserve real parent tablename for use below
v_parent_tablename := v_source_tablename;

SELECT general_type INTO v_control_type FROM @extschema@.check_control_type(v_source_schemaname, v_source_tablename, v_control);

IF v_control_type <> 'time' THEN
    IF (v_control_type = 'id' AND v_epoch = 'none') OR v_control_type <> 'id' THEN
        RAISE EXCEPTION 'Cannot run on partition set without time based control column or epoch flag set with an id column. Found control: %, epoch: %', v_control_type, v_epoch;
    END IF;
END IF;

-- Replace the parent variables with the source variables if using source table for child table data
IF p_source_table IS NOT NULL THEN
    -- Set source table to user given source table instead of parent table
    v_source_schemaname := NULL;
    v_source_tablename := NULL;

    SELECT schemaname, tablename INTO v_source_schemaname, v_source_tablename
    FROM pg_catalog.pg_tables
    WHERE schemaname = split_part(p_source_table, '.', 1)::name
    AND tablename = split_part(p_source_table, '.', 2)::name;

    IF v_source_tablename IS NULL THEN
        RAISE EXCEPTION 'Given source table does not exist in system catalogs: %', p_source_table;
    END IF;


ELSIF v_partition_type = 'native' AND current_setting('server_version_num')::int >= 110000 THEN

    IF p_batch_interval IS NOT NULL AND p_batch_interval != v_partition_interval THEN
        -- This is true because all data for a given child table must be moved out of the default partition before the child table can be created.
        -- So cannot create the child table when only some of the data has been moved out of the default partition.
        RAISE EXCEPTION 'Custom intervals are not allowed when moving data out of the DEFAULT partition in a native set. Please leave p_interval/p_batch_interval parameters unset or NULL to allow use of partition set''s default partitioning interval.';
    END IF;
    -- Set source table to default table if PG11+, p_source_table is not set, and it exists
    -- Otherwise just return with a DEBUG that no data source exists
    v_sql := format('SELECT n.nspname::text, c.relname::text FROM
        pg_catalog.pg_inherits h
        JOIN pg_catalog.pg_class c ON c.oid = h.inhrelid
        JOIN pg_catalog.pg_namespace n ON c.relnamespace = n.oid
        WHERE h.inhparent = ''%I.%I''::regclass
        AND pg_get_expr(relpartbound, c.oid) = ''DEFAULT'''
        , v_source_schemaname
        , v_source_tablename);

    EXECUTE v_sql INTO v_default_schemaname, v_default_tablename;
    IF v_default_tablename IS NOT NULL THEN
        v_source_schemaname := v_default_schemaname;
        v_source_tablename := v_default_tablename;

        v_default_exists := true;
        EXECUTE format ('CREATE TEMP TABLE IF NOT EXISTS partman_temp_data_storage (LIKE %I.%I INCLUDING INDEXES)', v_source_schemaname, v_source_tablename);
    ELSE
        RAISE DEBUG 'No default table found when partition_data_id() was called';
        RETURN v_total_rows;
    END IF;
END IF;

SELECT current_setting('search_path') INTO v_old_search_path;
EXECUTE format('SELECT set_config(%L, %L, %L)', 'search_path', v_new_search_path, 'false');

IF p_batch_interval IS NULL OR p_batch_interval > v_partition_interval THEN
    p_batch_interval := v_partition_interval;
END IF;

SELECT partition_tablename INTO v_last_partition FROM @extschema@.show_partitions(p_parent_table, 'DESC') LIMIT 1;

v_partition_expression := CASE
    WHEN v_epoch = 'seconds' THEN format('to_timestamp(%I)', v_control)
    WHEN v_epoch = 'milliseconds' THEN format('to_timestamp((%I/1000)::float)', v_control)
    ELSE format('%I', v_control)
END;

FOR i IN 1..p_batch_count LOOP

    IF p_order = 'ASC' THEN
        EXECUTE format('SELECT min(%s) FROM ONLY %I.%I', v_partition_expression, v_source_schemaname, v_source_tablename) INTO v_start_control;
    ELSIF p_order = 'DESC' THEN
        EXECUTE format('SELECT max(%s) FROM ONLY %I.%I', v_partition_expression, v_source_schemaname, v_source_tablename) INTO v_start_control;
    ELSE
        RAISE EXCEPTION 'Invalid value for p_order. Must be ASC or DESC';
    END IF;

    IF v_start_control IS NULL THEN
        EXIT;
    END IF;

    IF v_partition_type = 'partman' THEN
        CASE
            WHEN v_partition_interval = '15 mins' THEN
                v_min_partition_timestamp := date_trunc('hour', v_start_control) +
                    '15min'::interval * floor(date_part('minute', v_start_control) / 15.0);
            WHEN v_partition_interval = '30 mins' THEN
                v_min_partition_timestamp := date_trunc('hour', v_start_control) +
                    '30min'::interval * floor(date_part('minute', v_start_control) / 30.0);
            WHEN v_partition_interval = '1 hour' THEN
                v_min_partition_timestamp := date_trunc('hour', v_start_control);
            WHEN v_partition_interval = '1 day' THEN
                v_min_partition_timestamp := date_trunc('day', v_start_control);
            WHEN v_partition_interval = '1 week' THEN
                v_min_partition_timestamp := date_trunc('week', v_start_control);
            WHEN v_partition_interval = '1 month' THEN
                v_min_partition_timestamp := date_trunc('month', v_start_control);
            WHEN v_partition_interval = '3 months' THEN
                v_min_partition_timestamp := date_trunc('quarter', v_start_control);
            WHEN v_partition_interval = '1 year' THEN
                v_min_partition_timestamp := date_trunc('year', v_start_control);
        END CASE;
    ELSIF v_partition_type IN ('time-custom', 'native') THEN
        SELECT child_start_time INTO v_min_partition_timestamp FROM @extschema@.show_partition_info(v_source_schemaname||'.'||v_last_partition
            , v_partition_interval::text
            , p_parent_table);
        v_max_partition_timestamp := v_min_partition_timestamp + v_partition_interval;
        LOOP
            IF v_start_control >= v_min_partition_timestamp AND v_start_control < v_max_partition_timestamp THEN
                EXIT;
            ELSE
                BEGIN
                    IF v_start_control >= v_max_partition_timestamp THEN
                        -- Keep going forward in time, checking if child partition time interval encompasses the current v_start_control value
                        v_min_partition_timestamp := v_max_partition_timestamp;
                        v_max_partition_timestamp := v_max_partition_timestamp + v_partition_interval;

                    ELSE
                        -- Keep going backwards in time, checking if child partition time interval encompasses the current v_start_control value
                        v_max_partition_timestamp := v_min_partition_timestamp;
                        v_min_partition_timestamp := v_min_partition_timestamp - v_partition_interval;
                    END IF;
                EXCEPTION WHEN datetime_field_overflow THEN
                    RAISE EXCEPTION 'Attempted partition time interval is outside PostgreSQL''s supported time range.
                        Unable to create partition with interval before timestamp % ', v_min_partition_timestamp;
                END;
            END IF;
        END LOOP;

    END IF;

    v_partition_timestamp := ARRAY[v_min_partition_timestamp];
    IF p_order = 'ASC' THEN
        -- Ensure batch interval given as parameter doesn't cause maximum to overflow the current partition maximum
        IF (v_start_control + p_batch_interval) >= (v_min_partition_timestamp + v_partition_interval) THEN
            v_max_partition_timestamp := v_min_partition_timestamp + v_partition_interval;
        ELSE
            v_max_partition_timestamp := v_start_control + p_batch_interval;
        END IF;
    ELSIF p_order = 'DESC' THEN
        -- Must be greater than max value still in parent table since query below grabs < max
        v_max_partition_timestamp := v_min_partition_timestamp + v_partition_interval;
        -- Ensure batch interval given as parameter doesn't cause minimum to underflow current partition minimum
        IF (v_start_control - p_batch_interval) >= v_min_partition_timestamp THEN
            v_min_partition_timestamp = v_start_control - p_batch_interval;
        END IF;
    ELSE
        RAISE EXCEPTION 'Invalid value for p_order. Must be ASC or DESC';
    END IF;

-- do some locking with timeout, if required
    IF p_lock_wait > 0  THEN
        v_lock_iter := 0;
        WHILE v_lock_iter <= 5 LOOP
            v_lock_iter := v_lock_iter + 1;
            BEGIN
                EXECUTE format('SELECT * FROM ONLY %I.%I WHERE %s >= %L AND %3$s < %5$L FOR UPDATE NOWAIT'
                    , v_source_schemaname
                    , v_source_tablename
                    , v_partition_expression
                    , v_min_partition_timestamp
                    , v_max_partition_timestamp);
                v_lock_obtained := TRUE;
            EXCEPTION
                WHEN lock_not_available THEN
                    PERFORM pg_sleep( p_lock_wait / 5.0 );
                    CONTINUE;
            END;
            EXIT WHEN v_lock_obtained;
        END LOOP;
        IF NOT v_lock_obtained THEN
           RETURN -1;
        END IF;
    END IF;

    -- This suffix generation code is in create_partition_time() as well
    v_partition_suffix := to_char(v_min_partition_timestamp, v_datetime_string);
    v_current_partition_name := @extschema@.check_name_length(v_parent_tablename, v_partition_suffix, TRUE);

    IF v_default_exists THEN
        -- Child tables cannot be created in native partitioning if data that belongs to it exists in the default
        -- Have to move data out to temporary location, create child table, then move it back

        -- Temp table created above to avoid excessive temp creation in loop
        EXECUTE format('WITH partition_data AS (
                DELETE FROM %1$I.%2$I WHERE %3$I >= %4$L AND %3$I < %5$L RETURNING *)
            INSERT INTO partman_temp_data_storage SELECT * FROM partition_data'
            , v_source_schemaname
            , v_source_tablename
            , v_control
            , v_min_partition_timestamp
            , v_max_partition_timestamp);

        PERFORM @extschema@.create_partition_time(p_parent_table, v_partition_timestamp, p_analyze);

        EXECUTE format('WITH partition_data AS (
                DELETE FROM partman_temp_data_storage RETURNING *)
            INSERT INTO %I.%I SELECT * FROM partition_data'
            , v_source_schemaname
            , v_current_partition_name);

    ELSE

        PERFORM @extschema@.create_partition_time(p_parent_table, v_partition_timestamp, p_analyze);

        EXECUTE format('WITH partition_data AS (
                            DELETE FROM ONLY %I.%I WHERE %s >= %L AND %3$s < %5$L RETURNING *)
                         INSERT INTO %I.%I SELECT * FROM partition_data'
                            , v_source_schemaname
                            , v_source_tablename
                            , v_partition_expression
                            , v_min_partition_timestamp
                            , v_max_partition_timestamp
                            , v_source_schemaname
                            , v_current_partition_name);
    END IF;

    GET DIAGNOSTICS v_rowcount = ROW_COUNT;
    v_total_rows := v_total_rows + v_rowcount;
    IF v_rowcount = 0 THEN
        EXIT;
    END IF;

END LOOP;

IF v_partition_type IN ('partman', 'time-custom') THEN
    PERFORM @extschema@.create_function_time(p_parent_table);
END IF;

EXECUTE format('SELECT set_config(%L, %L, %L)', 'search_path', v_old_search_path, 'false');

RETURN v_total_rows;

END
$$;
