| Parameter | Description |
|---|---|
domino.decoder_info() |
Displays decoder information for the current database. |
domino.decoder_info_all() |
Displays decoder information for all databases. |
domino.decoder_workers() |
Queries the PID of worker processes and the databases they are connected to. |
domino.decoder_metrics() |
Shows performance counters for decoders. |
domino.stream_metrics() |
Shows scheduling performance counters and error information for streams. |
domino.stream_strategy() |
Displays scheduling strategy and status for streams. |
domino.stream_progress() |
Shows stream progress and XLog retention status. |
domino.ticker_info() |
Checks whether the ticker is running or paused. |
domino.ticker_metric() |
Shows what conditions triggered the ticker. |
domino.tlog_page(text) |
Displays TLog content; used for debugging. |
Usage Examples
domino.decoder_workers(): Query worker PIDs and connected databases.
=# select * from domino.decoder_workers();
segid | dbid | dbname | pid
-------+-------+--------+-------
0 | 18745 | haoyu | 20351
1 | 18745 | haoyu | 20353
2 | 18745 | haoyu | 20352
-1 | 18745 | haoyu | 20354
(4 rows)domino.decoder_metrics(): View performance counters for decoders.
=# select * from domino.decoder_metrics();
segid | dbid | dbname | bytes_in | xacts | spills | tuples_new | tuples_old | snapshots | latency_ms | loops | total_duration_ms | last_duration_ms
-------+-------+--------+----------+-------+--------+------------+------------+-----------+------------+-------+-------------------+------------------
0 | 18745 | haoyu | 36048 | 0 | 0 | 0 | 0 | 119 | 0 | 25851 | 26616 | 1
1 | 18745 | haoyu | 35872 | 0 | 0 | 0 | 0 | 119 | 0 | 26755 | 27517 | 1
2 | 18745 | haoyu | 36048 | 0 | 0 | 0 | 0 | 119 | 0 | 25814 | 26576 | 1
-1 | 18745 | haoyu | 36784 | 0 | 0 | 0 | 0 | 119 | 0 | 22781 | 23444 | 1
(4 rows)domino.stream_metrics(): View stream scheduling performance counters and error messages.
=# select * from domino.stream_metrics();
db | db_name | stream | stream_name | loops | tuples | total_slip_ms | last_slip_ms | last_lag_ms | total_duration_ms | last_duration_ms | last_run | held_until | has_error | error_message | error_detail | error_hint | error_context
-------+---------+--------+-------------+-------+--------+---------------+--------------+-------------+-------------------+------------------+-------------------------------+-------------------------------+-----------+---------------+--------------+------------+---------------
18745 | haoyu | 18792 | s1 | 4 | 0 | 6 | 2 | 1709 | 57 | 7 | 2025-05-23 14:14:26.249188+08 | 2025-05-23 14:14:27.242299+08 | f | | | |
(1 row)domino.stream_strategy(): View stream scheduling strategy and status.
=# select * from domino.stream_strategy();
id | db | db_name | stream | stream_name | strategy | summary
----+-------+---------+--------+-------------+------------+------------------------------------------
0 | 18745 | haoyu | 18792 | s1 | roundrobin | held until 2025-05-23 14:14:56.279678+08
(1 row)domino.stream_progress(): View stream progress and XLog retention status.
=# select * from domino.stream_progress();
segid | db | db_name | stream | stream_name | restart_lsn | flush_lsn | tsn | xmin | end_lsn | lag_size | pending_xid | pending_restart | pending_flush | pending_tsn | pending_xmin | wal_status | safe_wal_size
-------+-------+---------+--------+-------------+-------------+-----------+---------+------+-----------+----------+-------------+-----------------+---------------+-------------+--------------+------------+---------------
0 | 18745 | haoyu | 18792 | s1 | 0/C246788 | 0/C249420 | 0/1A160 | 645 | 0/C249CE0 | 2240 | 647 | 0/C246788 | 0/C249610 | 0/1A240 | 646 | reserved |
1 | 18745 | haoyu | 18792 | s1 | 0/C2466F0 | 0/C249388 | 0/1A160 | 645 | 0/C249C48 | 2240 | 647 | 0/C2466F0 | 0/C249578 | 0/1A240 | 646 | reserved |
2 | 18745 | haoyu | 18792 | s1 | 0/C246788 | 0/C249420 | 0/1A160 | 645 | 0/C249CE0 | 2240 | 647 | 0/C246788 | 0/C249610 | 0/1A240 | 646 | reserved |
(3 rows)domino.ticker_info(): Check whether the ticker is running or paused.
-- Return values: (invalid: not started, running: active, paused: paused)
ticker_info
-------------
running
(1 row)domino.ticker_metric(): View conditions that trigger the ticker.
=# SELECT * FROM domino.ticker_metric();
segid | ticks_by_time | ticks_by_size | ticks_by_force
-------+---------------+---------------+----------------
0 | 18894 | 2 | 1
1 | 18894 | 2 | 1
2 | 18894 | 2 | 1
-1 | 0 | 0 | 0
(4 rows)The Domino plugin provides two views: domino.decoder_info and domino.stream_info, used to monitor the status and metrics of logical decoders and data streams.
domino.decoder_info displays the runtime status and metrics of logical decoders on each segment.
Field Descriptions
| Field Name | Type | Description |
|---|---|---|
| segid | integer | Segment ID |
| dbid | oid | Database OID |
| dbname | text | Database name |
| restart_lsn | pg_lsn | Starting LSN of XLog retained (XLog is retained from this position) |
| confirmed_flush | pg_lsn | Flush LSN of XLog |
| start_tsn | pg_lsn | Start TSN of the last generated TLog |
| end_tsn | pg_lsn | End TSN of the last generated TLog |
| prog_xmin | xid | xmin of catalog/dimension tables (data is retained based on this xid) |
| pid | integer | Decoder process ID; 0 means not running |
| bytes_in | bigint | Total volume of consumed XLog data |
| xacts | bigint | Total number of transactions consumed |
| spills | bigint | Number of transactions spilled to disk |
| tuples_new | bigint | Number of inserted rows |
| tuples_old | bigint | Number of updated/deleted old rows |
| snapshots | bigint | Number of snapshots generated |
| latency_ms | bigint | Latency of the last decoding cycle |
| loops | bigint | Number of decoder execution cycles |
| total_duration_ms | bigint | Cumulative execution time |
| last_duration_ms | bigint | Duration of the last execution cycle |
Query Example
-- Check segments with high decoding latency
SELECT segid, dbid, dbname, dbname, latency_ms
FROM domino.decoder_info
WHERE latency_ms > 60 * 1000;domino.stream_info displays overall progress, status, and scheduling information for each logical stream.
Field Descriptions
| Field Name | Type | Description |
|---|---|---|
| segid | integer | Segment ID |
| db | oid | Database OID |
| db_name | text | Database name |
| stream | oid | Stream OID |
| stream_name | text | Stream name |
| restart_lsn | pg_lsn | Starting LSN of XLog retained (XLog is retained from this position) |
| flush_lsn | pg_lsn | Flush LSN of XLog |
| start_tsn | pg_lsn | Start TSN of the last consumed TLog |
| end_tsn | pg_lsn | End TSN of the last consumed TLog |
| xmin | xid | xmin of catalog/dimension tables (data is retained based on this xid) |
| end_lsn | pg_lsn | Latest LSN on this segment |
| lag_size | bigint | Size difference between flush_lsn and end_lsn |
| pending_xid | xid | Uncommitted transaction ID |
| pending_restart | pg_lsn | Uncommitted XLog restart LSN (XLog is retained from this position) |
| pending_flush | pg_lsn | Uncommitted XLog flush LSN |
| pending_tsn | pg_lsn | Uncommitted TLog start TSN |
| pending_xmin | xid | Uncommitted xmin of catalog/dimension tables |
| wal_status | text | WAL status: active: within max_wal_size limit, not cleaned; reserved: exceeds max_wal_size but protected by logical slot or stream, not cleaned; unprotected: beyond protection of slot and stream, will be cleaned at next checkpoint; removed: already cleaned |
| safe_wal_size | bigint | Safe maximum WAL size limit; WAL beyond this size may be cleaned |
| loops | bigint | Number of execution cycles |
| tuples | bigint | Number of processed rows |
| total_slip_ms | bigint | Cumulative sleep time (task scheduling delay) |
| last_slip_ms | bigint | Last sleep duration |
| last_lag_ms | bigint | Stream processing delay (time difference between last processed tick and latest tick) |
| total_duration_ms | bigint | Total execution time |
| last_duration_ms | bigint | Duration of last execution |
| last_run | timestamp with time zone | Last execution time |
| held_until | timestamp with time zone | Next scheduled execution time (on error, sleeps for one minute before retry) |
| has_error | boolean | Whether an error occurred |
| error_message | text | Error message |
| error_detail | text | Error details |
| error_hint | text | Error hint |
| error_context | text | Error context |
| slot_id | integer | Domino worker slot in use |
| strategy | text | Scheduling strategy |
| summary | text | Summary of strategy description |
Query Examples
-- Check all streams with errors
SELECT stream_name, error_message
FROM domino.stream_info
WHERE has_error;
-- Check streams with large lag
SELECT stream_name, pg_size_pretty(lag_size) AS lag
FROM domino.stream_info
WHERE lag_size > 64*1024*1024;| Function | Description |
|---|---|
domino.start_all() |
Starts all components. After plugin creation, v2 components do not start automatically on restart; manual start is required. |
domino.stop_all() |
Stops all components. |
domino.start_decoder() |
Starts the decoder. |
domino.stop_decoder() |
Stops the decoder. |
domino.start_ticker() |
Starts the ticker. |
domino.stop_ticker() |
Stops the ticker. |
domino.pause_ticker() |
Pauses the ticker. |
domino.resume_ticker() |
Resumes the ticker. |
domino.reset_ticker() |
Resets the ticker. |
domino.wait_next_tick() |
Waits for the next tick. |
Used primarily for troubleshooting.
| Function | Description |
|---|---|
domino.wait_for_decoder() |
Waits for the decoder to catch up. |
domino.wait_for_stream() |
Waits for the stream to catch up. |
domino.pause_stream(oid) |
Pauses a specific stream. |
domino.pause_all_streams() |
Pauses all streams. |
domino.resume_stream(oid) |
Resumes a specific stream. |
domino.resume_all_streams() |
Resumes all streams. |
domino.rotate_tlog() |
Rotates TLog file (Segment). |