greptimedb/tests/cases/standalone/common/flow/flow_incremental_memtable.result

-- Validate that a flow performing an incremental aggregate read only reads memtable
-- data and does NOT re-read source rows that have already been flushed to SST after
-- a previous checkpoint.
CREATE TABLE flow_incr_memtable_input (
    host_id INT,
    n INT,
    ts TIMESTAMP TIME INDEX,
    PRIMARY KEY(host_id)
) WITH (
    append_mode = 'true'
);

Affected Rows: 0

CREATE FLOW flow_incr_memtable SINK TO flow_incr_memtable_sink
WITH (experimental_enable_incremental_read = 'true')
AS
SELECT
    sum(n) AS total,
    min(n) AS min_n,
    max(n) AS max_n,
    date_bin(INTERVAL '1 minute', ts, '2024-01-01 00:00:00') AS time_window
FROM
    flow_incr_memtable_input
GROUP BY
    time_window;

Affected Rows: 0

-- ==== Phase 1: initial insert + checkpoint ====
INSERT INTO flow_incr_memtable_input VALUES
    (1, 10, '2024-01-01 00:00:00'),
    (2, 20, '2024-01-01 00:00:30');

Affected Rows: 2

-- SQLNESS REPLACE (ADMIN\sFLUSH_FLOW\('\w+'\)\s+\|\n\+-+\+\n\|\s+)[0-9]+\s+\| $1 FLOW_FLUSHED  |
ADMIN FLUSH_FLOW('flow_incr_memtable');

+----------------------------------------+
| ADMIN FLUSH_FLOW('flow_incr_memtable') |
+----------------------------------------+
|  FLOW_FLUSHED  |
+----------------------------------------+

SELECT total, min_n, max_n, time_window FROM flow_incr_memtable_sink ORDER BY time_window;

+-------+-------+-------+---------------------+
| total | min_n | max_n | time_window         |
+-------+-------+-------+---------------------+
| 30    | 10    | 20    | 2024-01-01T00:00:00 |
+-------+-------+-------+---------------------+

-- ==== Phase 2: flush sink and source tables to SST ====
-- The next incremental run must still read the flushed sink aggregate state,
-- while skipping already-checkpointed source SST files.
ADMIN FLUSH_TABLE('flow_incr_memtable_sink');

+----------------------------------------------+
| ADMIN FLUSH_TABLE('flow_incr_memtable_sink') |
+----------------------------------------------+
| 0                                            |
+----------------------------------------------+

ADMIN FLUSH_TABLE('flow_incr_memtable_input');

+-----------------------------------------------+
| ADMIN FLUSH_TABLE('flow_incr_memtable_input') |
+-----------------------------------------------+
| 0                                             |
+-----------------------------------------------+

-- ==== Phase 3: empty incremental window ====
-- Flush the flow without inserting any new source rows to verify that
-- the incremental read correctly handles the case where no new memtable
-- data exists.
-- SQLNESS REPLACE (ADMIN\sFLUSH_FLOW\('\w+'\)\s+\|\n\+-+\+\n\|\s+)[0-9]+\s+\| $1 FLOW_FLUSHED  |
ADMIN FLUSH_FLOW('flow_incr_memtable');

+----------------------------------------+
| ADMIN FLUSH_FLOW('flow_incr_memtable') |
+----------------------------------------+
|  FLOW_FLUSHED  |
+----------------------------------------+

SELECT total, min_n, max_n, time_window FROM flow_incr_memtable_sink ORDER BY time_window;

+-------+-------+-------+---------------------+
| total | min_n | max_n | time_window         |
+-------+-------+-------+---------------------+
| 30    | 10    | 20    | 2024-01-01T00:00:00 |
+-------+-------+-------+---------------------+

-- ==== Phase 4: insert new delta within the same time window ====
INSERT INTO flow_incr_memtable_input VALUES
    (3, 30, '2024-01-01 00:00:15'),
    (4, 40, '2024-01-01 00:00:45');

Affected Rows: 2

-- ==== Phase 5: flush flow again (incremental read) ====
-- The flow must only read the new memtable delta and merge with the existing
-- sink aggregate. If it mistakenly re-reads the SST, the result will be
-- inflated (initial data counted twice).
-- SQLNESS REPLACE (ADMIN\sFLUSH_FLOW\('\w+'\)\s+\|\n\+-+\+\n\|\s+)[0-9]+\s+\| $1 FLOW_FLUSHED  |
ADMIN FLUSH_FLOW('flow_incr_memtable');

+----------------------------------------+
| ADMIN FLUSH_FLOW('flow_incr_memtable') |
+----------------------------------------+
|  FLOW_FLUSHED  |
+----------------------------------------+

SELECT total, min_n, max_n, time_window FROM flow_incr_memtable_sink ORDER BY time_window;

+-------+-------+-------+---------------------+
| total | min_n | max_n | time_window         |
+-------+-------+-------+---------------------+
| 100   | 10    | 40    | 2024-01-01T00:00:00 |
+-------+-------+-------+---------------------+

-- Clean up
DROP FLOW flow_incr_memtable;

Affected Rows: 0

DROP TABLE flow_incr_memtable_input;

Affected Rows: 0

DROP TABLE flow_incr_memtable_sink;

Affected Rows: 0