ALTER TABLE RESUME WAL
Restarts transactions of a WAL table after recovery from errors.
Syntax
Description
sequencerTxn
is the unique txn
identification that the Sequencer issues to
transactions.
When sequencerTxn
is not specified, the operation resumes the WAL apply job
from the next uncommitted transaction, including the failed one.
When sequencerTxn
is not specified, the operation resumes the WAL apply job
from the provided sequencerTxn
number explicitly.
ALTER TABLE RESUME WAL
is used to restart WAL table transactions after
resolving errors. When transactions are stopped, the suspended
status from the
wal_tables()
function is marked
as true
, and the sequencerTxn
value indicates the last successful commit in
the Sequencer. Once the error is resolved, ALTER TABLE RESUME WAL
restarts the
suspended WAL transactions from the failed transaction. Alternatively, an
optional sequencerTxn
value can be provided to skip the failed transaction.
Examples
Using the wal_tables()
function
to investigate the table status:
wal_tables();
name | suspended | writerTxn | sequencerTxn |
---|---|---|---|
sensor_wal | false | 6 | 6 |
weather_wal | true | 3 | 5 |
The table weather_wal
is suspended. The last successful commit in the table is
3
.
The following query restarts transactions from the failed transaction, 4
:
ALTER TABLE weather_wal RESUME WAL;
Alternatively, specifying the sequencerTxn
to skip the failed commit (4
in
this case):
ALTER TABLE weather_wal RESUME WAL FROM TRANSACTION 5;
-- This is equivalent to
ALTER TABLE weather_wal RESUME WAL FROM TXN 5;