create_time_partition.sql

/*
 * Function to create a child table in a time-based partition set
 */
CREATE FUNCTION create_time_partition (p_parent_table text, p_partition_times timestamp[]) 
RETURNS text
    LANGUAGE plpgsql SECURITY DEFINER
    AS $$
DECLARE

v_all                           text[] := ARRAY['SELECT', 'INSERT', 'UPDATE', 'DELETE', 'TRUNCATE', 'REFERENCES', 'TRIGGER'];
v_analyze                       boolean := FALSE;
v_control                       text;
v_grantees                      text[];
v_hasoids                       boolean;
v_job_id                        bigint;
v_jobmon                        boolean;
v_jobmon_schema                 text;
v_old_search_path               text;
v_parent_grant                  record;
v_parent_owner                  text;
v_parent_schema                 text;
v_parent_tablename              text;
v_partition_name                text;
v_partition_suffix              text;
v_parent_tablespace             text;
v_part_interval                 interval;
v_partition_timestamp_end       timestamp;
v_partition_timestamp_start     timestamp;
v_quarter                       text;
v_revoke                        text[];
v_sql                           text;
v_step_id                       bigint;
v_step_overflow_id              bigint;
v_tablename                     text;
v_trunc_value                   text;
v_time                          timestamp;
v_type                          text;
v_unlogged                      char;
v_year                          text;

BEGIN

SELECT type
    , control
    , part_interval
    , jobmon
INTO v_type
    , v_control
    , v_part_interval
    , v_jobmon
FROM @extschema@.part_config
WHERE parent_table = p_parent_table
AND (type = 'time-static' OR type = 'time-dynamic' OR type = 'time-custom');

IF NOT FOUND THEN
    RAISE EXCEPTION 'ERROR: no config found for %', p_parent_table;
END IF;

IF v_jobmon THEN
    SELECT nspname INTO v_jobmon_schema FROM pg_namespace n, pg_extension e WHERE e.extname = 'pg_jobmon' AND e.extnamespace = n.oid;
    IF v_jobmon_schema IS NOT NULL THEN
        SELECT current_setting('search_path') INTO v_old_search_path;
        EXECUTE 'SELECT set_config(''search_path'',''@extschema@,'||v_jobmon_schema||''',''false'')';
    END IF;
END IF;

SELECT tableowner, schemaname, tablename, tablespace INTO v_parent_owner, v_parent_schema, v_parent_tablename, v_parent_tablespace FROM pg_tables WHERE schemaname ||'.'|| tablename = p_parent_table;

FOREACH v_time IN ARRAY p_partition_times LOOP    

    v_partition_suffix := to_char(v_time, 'YYYY');
    IF v_part_interval < '1 year' AND v_part_interval <> '1 week' THEN 
        v_partition_suffix := v_partition_suffix ||'_'|| to_char(v_time, 'MM');
        IF v_part_interval < '1 month' AND v_part_interval <> '1 week' THEN 
            v_partition_suffix := v_partition_suffix ||'_'|| to_char(v_time, 'DD');
            IF v_part_interval < '1 day' THEN
                v_partition_suffix := v_partition_suffix || '_' || to_char(v_time, 'HH24MI');
                IF v_part_interval < '1 minute' THEN
                    v_partition_suffix := v_partition_suffix || to_char(v_time, 'SS');
                END IF; -- end < minute IF
            END IF; -- end < day IF      
        END IF; -- end < month IF
    END IF; -- end < year IF

    v_partition_timestamp_start := v_time;
    BEGIN
        v_partition_timestamp_end := v_time + v_part_interval;
    EXCEPTION WHEN datetime_field_overflow THEN
        RAISE WARNING 'Attempted partition time interval is outside PostgreSQL''s supported time range. 
            Child partition creation after time % skipped', v_time;
        v_step_overflow_id := add_step(v_job_id, 'Attempted partition time interval is outside PostgreSQL''s supported time range.');
        PERFORM update_step(v_step_overflow_id, 'CRITICAL', 'Child partition creation after time '||v_time||' skipped');
        CONTINUE;
    END;

    IF v_part_interval = '1 week' THEN
        v_partition_suffix := to_char(v_time, 'IYYY') || 'w' || to_char(v_time, 'IW');
    END IF;
 
    -- "Q" is ignored in to_timestamp, so handle special case
    IF v_part_interval = '3 months' AND (v_type = 'time-static' OR v_type = 'time-dynamic') THEN
        v_year := to_char(v_time, 'YYYY');
        v_quarter := to_char(v_time, 'Q');
        v_partition_suffix := v_year || 'q' || v_quarter;
    END IF;

    v_partition_name := @extschema@.check_name_length(v_parent_tablename, v_parent_schema, v_partition_suffix, TRUE);

    SELECT tablename INTO v_tablename FROM pg_catalog.pg_tables WHERE schemaname ||'.'|| tablename = v_partition_name;
    IF v_tablename IS NOT NULL THEN
        CONTINUE;
    END IF;

    -- Ensure analyze is run if a new partition is created. Otherwise if one isn't, will be false and analyze will be skipped
    v_analyze := TRUE;

    IF v_jobmon_schema IS NOT NULL THEN
        v_job_id := add_job('PARTMAN CREATE TABLE: '||p_parent_table);
        v_step_id := add_step(v_job_id, 'Creating new partition '||v_partition_name||' with interval from '||v_partition_timestamp_start||' to '||(v_partition_timestamp_end-'1sec'::interval));
    END IF;

    SELECT relpersistence INTO v_unlogged FROM pg_catalog.pg_class WHERE oid::regclass = p_parent_table::regclass;
    v_sql := 'CREATE';
    IF v_unlogged = 'u' THEN
        v_sql := v_sql || ' UNLOGGED';
    END IF;
    v_sql := v_sql || ' TABLE '||v_partition_name||' (LIKE '||p_parent_table||' INCLUDING DEFAULTS INCLUDING CONSTRAINTS INCLUDING INDEXES INCLUDING STORAGE INCLUDING COMMENTS)';
    SELECT relhasoids INTO v_hasoids FROM pg_catalog.pg_class WHERE oid::regclass = p_parent_table::regclass;
    IF v_hasoids IS TRUE THEN
        v_sql := v_sql || ' WITH (OIDS)';
    END IF;
    EXECUTE v_sql;
    SELECT tablename INTO v_tablename FROM pg_catalog.pg_tables WHERE schemaname ||'.'|| tablename = v_partition_name;
    IF v_parent_tablespace IS NOT NULL THEN
        EXECUTE 'ALTER TABLE '||v_partition_name||' SET TABLESPACE '||v_parent_tablespace;
    END IF;
    EXECUTE 'ALTER TABLE '||v_partition_name||' ADD CONSTRAINT '||v_tablename||'_partition_check
        CHECK ('||v_control||'>='||quote_literal(v_partition_timestamp_start)||' AND '||v_control||'<'||quote_literal(v_partition_timestamp_end)||')';
    EXECUTE 'ALTER TABLE '||v_partition_name||' INHERIT '||p_parent_table;

    -- If custom time, set extra config options.
    IF v_type = 'time-custom' THEN
        INSERT INTO @extschema@.custom_time_partitions (parent_table, child_table, partition_range)
        VALUES ( p_parent_table, v_partition_name, tstzrange(v_partition_timestamp_start, v_partition_timestamp_end, '[)') );
    END IF;

    FOR v_parent_grant IN 
        SELECT array_agg(DISTINCT privilege_type::text ORDER BY privilege_type::text) AS types, grantee
        FROM information_schema.table_privileges 
        WHERE table_schema ||'.'|| table_name = p_parent_table
        GROUP BY grantee 
    LOOP
        EXECUTE 'GRANT '||array_to_string(v_parent_grant.types, ',')||' ON '||v_partition_name||' TO '||v_parent_grant.grantee;
        SELECT array_agg(r) INTO v_revoke FROM (SELECT unnest(v_all) AS r EXCEPT SELECT unnest(v_parent_grant.types)) x;
        IF v_revoke IS NOT NULL THEN
            EXECUTE 'REVOKE '||array_to_string(v_revoke, ',')||' ON '||v_partition_name||' FROM '||v_parent_grant.grantee||' CASCADE';
        END IF;
        v_grantees := array_append(v_grantees, v_parent_grant.grantee::text);
    END LOOP;
    -- Revoke all privileges from roles that have none on the parent
    IF v_grantees IS NOT NULL THEN
        SELECT array_agg(r) INTO v_revoke FROM (
            SELECT DISTINCT grantee::text AS r FROM information_schema.table_privileges WHERE table_schema ||'.'|| table_name = v_partition_name
            EXCEPT
            SELECT unnest(v_grantees)) x;
        IF v_revoke IS NOT NULL THEN
            EXECUTE 'REVOKE ALL ON '||v_partition_name||' FROM '||array_to_string(v_revoke, ',');
        END IF;
    END IF;

    EXECUTE 'ALTER TABLE '||v_partition_name||' OWNER TO '||v_parent_owner;

    PERFORM @extschema@.apply_foreign_keys(quote_ident(v_parent_schema)||'.'||quote_ident(v_parent_tablename), v_partition_name);

    IF v_jobmon_schema IS NOT NULL THEN
        PERFORM update_step(v_step_id, 'OK', 'Done');
        IF v_step_overflow_id IS NOT NULL THEN
            PERFORM fail_job(v_job_id);
        ELSE
            PERFORM close_job(v_job_id);
        END IF;
    END IF;

END LOOP;

IF v_analyze THEN
    EXECUTE 'ANALYZE '||p_parent_table;
END IF;

IF v_jobmon_schema IS NOT NULL THEN
    EXECUTE 'SELECT set_config(''search_path'','''||v_old_search_path||''',''false'')';
END IF;

RETURN v_partition_name;

EXCEPTION
    WHEN OTHERS THEN
        IF v_jobmon_schema IS NOT NULL THEN
            IF v_job_id IS NULL THEN
                EXECUTE 'SELECT '||v_jobmon_schema||'.add_job(''PARTMAN CREATE TABLE: '||p_parent_table||''')' INTO v_job_id;
                EXECUTE 'SELECT '||v_jobmon_schema||'.add_step('||v_job_id||', ''EXCEPTION before job logging started'')' INTO v_step_id;
            ELSIF v_step_id IS NULL THEN
                EXECUTE 'SELECT '||v_jobmon_schema||'.add_step('||v_job_id||', ''EXCEPTION before first step logged'')' INTO v_step_id;
            END IF;
            EXECUTE 'SELECT '||v_jobmon_schema||'.update_step('||v_step_id||', ''CRITICAL'', ''ERROR: '||coalesce(SQLERRM,'unknown')||''')';
            EXECUTE 'SELECT '||v_jobmon_schema||'.fail_job('||v_job_id||')';
        END IF;
        RAISE EXCEPTION '%', SQLERRM;
END
$$;