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10.4.40. TimeDelay (delay) Filter

The TimeDelayFilter delays writing events to the THL and should be used only on slaves in the remote-to-thl stage. This delays writing the transactions into the THL files, but allows the application of the slave data to the database to continue without further intervention.

Pre-configured filter name delay
Classname com.continuent.tungsten.replicator.filter.TimeDelayFilter
Property prefix replicator.filter.delay
Stage compatibility remote-to-thl
tpm Option compatibility --repl-svc-thl-filters
Data compatibility Any event
Parameters
Parameter Type Default Description
delay numeric 300 Number of seconds to delay transaction processing row

The TimeDelay delays the application of transactions recorded in the THL. The delay can be used to allow point-in-time recovery of DML operations before the transaction has been applied to the slave, or where data may need to be audited or checked before transactions are committed.

Note

For effective operation, master and slaves should be synchronized using NTP or a similar protocol.

To enable the TimeDelayFilter, use tpm command to enable the filter operation and the required delay. For example, to enable the delay for 900 seconds:

shell> ./tools/tpm update alpha --hosts=host1,host2,host3 \
    --repl-svc-applier-filters=delay \
    --property=replicator.filter.delay.delay=900

Time delay of transaction events should be performed with care, since the delay will prevent a slave from being up to date compared to the master. In the event of a node failure, an up to date slave is required to ensure that data is safe.