timescaledb/sql/chunk.sql

289 lines
11 KiB
PL/PgSQL

-- Add a new partition epoch with equally sized partitions
CREATE OR REPLACE FUNCTION _timescaledb_internal.chunk_get(
time_dimension_id INTEGER,
time_value BIGINT,
space_dimension_id INTEGER,
space_dimension_hash BIGINT
)
RETURNS _timescaledb_catalog.chunk LANGUAGE SQL STABLE AS
$BODY$
SELECT *
FROM _timescaledb_catalog.chunk
WHERE
id = (
SELECT cc.chunk_id
FROM _timescaledb_catalog.dimension_slice ds
INNER JOIN _timescaledb_catalog.chunk_constraint cc ON (ds.id = cc.dimension_slice_id)
WHERE ds.dimension_id = time_dimension_id and ds.range_start <= time_value and ds.range_end >= time_value
INTERSECT
SELECT cc.chunk_id
FROM _timescaledb_catalog.dimension_slice ds
INNER JOIN _timescaledb_catalog.chunk_constraint cc ON (ds.id = cc.dimension_slice_id)
WHERE ds.dimension_id = space_dimension_id and ds.range_start <= space_dimension_hash and ds.range_end >= space_dimension_hash
)
$BODY$;
--todo: unit test
CREATE OR REPLACE FUNCTION _timescaledb_internal.dimension_calculate_default_range(
dimension_id INTEGER,
dimension_value BIGINT,
OUT range_start BIGINT,
OUT range_end BIGINT)
LANGUAGE PLPGSQL STABLE AS
$BODY$
DECLARE
dimension_row _timescaledb_catalog.dimension;
inter BIGINT;
BEGIN
SELECT *
INTO STRICT dimension_row
WHERE id = time_dimension_id;
IF dimension_row.interval_length IS NOT NULL THEN
range_start := (dimension_value / dimension_row.interval_length) * dimension_row.interval_length;
range_end := range_start + dimension_row.interval_length - 1;
ELSE
inter := (32768 / dimension_row.num_slices);
IF dimension_value >= inter * (dimension_row.num_slices - 1) THEN
--put overflow from integer-division errors in last range
range_start = inter * (dimension_row.num_slices - 1);
range_end = 32768 - 1;
ELSE
range_start = (dimension_value / inter) * inter;
range_end := range_start + inter - 1;
END IF;
END IF;
END
$BODY$;
-- calculate the range for a free dimension.
-- assumes one other fixed dimension.
CREATE OR REPLACE FUNCTION _timescaledb_internal.chunk_calculate_new_ranges(
free_dimension_id INTEGER,
free_dimension_value BIGINT,
fixed_dimension_id INTEGER,
fixed_dimension_value BIGINT,
align BOOLEAN,
OUT new_range_start BIGINT = NULL,
OUT new_range_end BIGINT = NULL
)
LANGUAGE PLPGSQL STABLE AS
$BODY$
DECLARE
overlap_value BIGINT;
alignment_found := FALSE;
BEGIN
IF align THEN
--if i am aligning then fix see if other chunks have values that fit me in the free dimension
SELECT free_slice.range_start, free_slice.range_end
INTO new_range_start, new_range_end
FROM _timescaledb_catalog.chunk c
INNER JOIN _timescaledb_catalog.chunk_constraint cc ON (cc.chunk_id = c.chunk_id)
INNER JOIN _timescaledb_catalog.dimension_slice free_slice ON (ds.id = cc.dimension_slice_id AND ds.dimension_id = free_dimension_id)
WHERE
free_slice.range_end >= free_dimension_value and free_slice.range_start <= free_dimension_value
LIMIT 1;
SELECT new_range_start IS NOT NULL INTO alignment_found;
END IF;
IF NOT alignment_found THEN
--either not aligned or did not find an alignment
SELECT *
INTO new_range_start, new_range_end
FROM _timescaledb_internal.dimension_calculate_default_range(free_dimension_id, free_dimension_value);
END IF;
-- Check whether the new chunk interval overlaps with existing chunks.
-- new_range_start overlaps
SELECT free_slice.range_end
INTO overlap_value
FROM _timescaledb_catalog.chunk c
INNER JOIN _timescaledb_catalog.chunk_constraint cc ON (cc.chunk_id = c.chunk_id)
INNER JOIN _timescaledb_catalog.dimension_slice free_slice ON (ds.id = cc.dimension_slice_id AND ds.dimension_id = free_dimension_id)
WHERE
c.id = (
SELECT cc.chunk_id
FROM _timescaledb_catalog.dimension_slice ds
INNER JOIN _timescaledb_catalog.chunk_constraint cc ON (ds.id = cc.dimension_slice_id)
WHERE ds.dimension_id = free_dimension_id and ds.range_end <= new_range_end and ds.range_end >= new_range_start
INTERSECT
SELECT cc.chunk_id
FROM _timescaledb_catalog.dimension_slice ds
INNER JOIN _timescaledb_catalog.chunk_constraint cc ON (ds.id = cc.dimension_slice_id)
WHERE ds.dimension_id = fixed_dimension_id and ds.range_start <= fixed_dimension_value and ds.range_end >= fixed_dimension_value
)
ORDER BY free_slice.range_end DESC
LIMIT 1;
IF FOUND THEN
-- there is at least one ends inside cut the
-- start to match the last one
IF alignment_found THEN
RAISE EXCEPTION 'Should never happen: needed to cut an aligned dimension'
USING ERRCODE = 'IO501';
END IF;
new_range_start := overlap_value + 1;
END IF;
--check for new_range_end overlap
SELECT free_slice.range_start
INTO overlap_value
FROM _timescaledb_catalog.chunk c
INNER JOIN _timescaledb_catalog.chunk_constraint cc ON (cc.chunk_id = c.chunk_id)
INNER JOIN _timescaledb_catalog.dimension_slice free_slice ON (ds.id = cc.dimension_slice_id AND ds.dimension_id = free_dimension_id)
WHERE
c.id = (
SELECT cc.chunk_id
FROM _timescaledb_catalog.dimension_slice ds
INNER JOIN _timescaledb_catalog.chunk_constraint cc ON (ds.id = cc.dimension_slice_id)
WHERE ds.dimension_id = free_dimension_id and ds.range_start >= new_range_start and ds.range_start <= new_range_end
INTERSECT
SELECT cc.chunk_id
FROM _timescaledb_catalog.dimension_slice ds
INNER JOIN _timescaledb_catalog.chunk_constraint cc ON (ds.id = cc.dimension_slice_id)
WHERE ds.dimension_id = fixed_dimension_id and ds.range_start <= fixed_dimension_value and ds.range_end >= fixed_dimension_value
)
ORDER BY free_slice.range_start ASC
LIMIT 1;
IF FOUND THEN
-- there is at least one table that starts inside, cut the end to match
IF alignment_found THEN
RAISE EXCEPTION 'Should never happen: needed to cut an aligned dimension'
USING ERRCODE = 'IO501';
END IF;
new_range_end := overlap_value - 1;
END IF;
END
$BODY$;
-- creates the row in the chunk table. Prerequisite: appropriate lock.
-- static
CREATE OR REPLACE FUNCTION _timescaledb_internal.chunk_create_after_lock(
time_dimension_id INTEGER,
time_value BIGINT,
space_dimension_id INTEGER,
space_value BIGINT
)
RETURNS VOID LANGUAGE PLPGSQL VOLATILE AS
$BODY$
DECLARE
time_start BIGINT;
time_end BIGINT;
space_start BIGINT;
space_end BIGINT;
dimension_row _timescaledb_catalog.dimension;
BEGIN
SELECT *
INTO STRICT dimension_row
WHERE id = time_dimension_id;
SELECT *
INTO time_start, time_end
FROM _timescaledb_internal.chunk_calculate_new_ranges(time_dimension_id, time_value, space_dimension_id, space_value, true);
SELECT *
INTO space_start, space_end
FROM _timescaledb_internal.chunk_calculate_new_ranges(space_dimension_id, space_value, time_dimension_id, time_value, false);
--do not use RETURNING here (ON CONFLICT DO NOTHING)
INSERT INTO _timescaledb_catalog.dimension_slice (dimension_id, range_start, range_end)
VALUES(time_dimension_id, time_start, time_end) ON CONFLICT DO NOTHING;
INSERT INTO _timescaledb_catalog.dimension_slice (dimension_id, range_start, range_end)
VALUES(space_dimension_id, space_start, space_end) ON CONFLICT DO NOTHING;
WITH chunk AS (
INSERT INTO _timescaledb_catalog.chunk (id, hypertable_id, schema_name, table_name)
SELECT seq_id, h.id, h.associated_schema_name,
format('%s_%s_chunk', h.associated_table_prefix, seq_id)
FROM
nextval(pg_get_serial_sequence('_timescaledb_catalog.chunk','id')) seq_id,
_timescaledb_catalog.hypertable h
WHERE h.id = dimension_row.hypertable_id
RETURNING *
), space_slice AS (
SELECT *
FROM _timescaledb_catalog.dimension_slice
WHERE dimension_id = space_dimension_id AND
range_start = space_start AND
range_end = space_end
), time_slice AS (
SELECT *
FROM _timescaledb_catalog.dimension_slice
WHERE dimension_id = time_dimension_id AND
range_start = time_start AND
range_end = time_end
)
INSERT INTO chunk_constraint (dimension_slice_id, chunk_id)
SELECT space_slice.id, chunk.id FROM space_slice, chunk
UNION
SELECT time_slice.id, chunk.id FROM time_slice, chunk;
END
$BODY$;
-- Creates and returns a new chunk, taking a lock on the chunk table.
-- static
CREATE OR REPLACE FUNCTION _timescaledb_internal.chunk_create(
time_dimension_id INTEGER,
time_value BIGINT,
space_dimension_id INTEGER,
space_value BIGINT
)
RETURNS _timescaledb_catalog.chunk LANGUAGE PLPGSQL VOLATILE AS
$BODY$
DECLARE
chunk_row _timescaledb_catalog.chunk;
BEGIN
LOCK TABLE _timescaledb_catalog.chunk IN EXCLUSIVE MODE;
-- recheck:
chunk_row := _timescaledb_internal.chunk_get(time_dimension_id, time_value, space_dimension_id, space_value);
IF chunk_row IS NULL THEN
PERFORM _timescaledb_internal.chunk_create_after_lock(time_dimension_id, time_value, space_dimension_id, space_value);
chunk_row := _timescaledb_internal.chunk_get(time_dimension_id, time_value, space_dimension_id, space_value);
END IF;
IF chunk_row IS NULL THEN -- recheck
RAISE EXCEPTION 'Should never happen: chunk not found after creation on meta'
USING ERRCODE = 'IO501';
END IF;
RETURN chunk_row;
END
$BODY$;
-- Return a chunk, creating one if it doesn't exist.
-- This is the only non-static function in this file.
CREATE OR REPLACE FUNCTION _timescaledb_internal.chunk_get_or_create(
time_dimension_id INTEGER,
time_value BIGINT,
space_dimension_id INTEGER,
space_value BIGINT
)
RETURNS _timescaledb_catalog.chunk LANGUAGE PLPGSQL VOLATILE AS
$BODY$
DECLARE
chunk_row _timescaledb_catalog.chunk;
BEGIN
chunk_row := _timescaledb_internal.chunk_get(time_dimension_id, time_value, space_dimension_id, space_value);
IF chunk_row IS NULL THEN
chunk_row := _timescaledb_internal.chunk_create(time_dimension_id, time_value, space_dimension_id, space_value);
END IF;
RETURN chunk_row;
END
$BODY$;