Handling Replication Slot Drop Failures
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Hevo Edge Pipelines created with any variant of the PostgreSQL Source replicate data using the database logs and publications. For such a Pipeline, Hevo creates a replication slot in your Source system to ensure that any change in the database logs is propagated to all recipients.
If these replication slots are not dropped, they may fill up the space allotted by the PostgreSQL database for its log files. Hence, when you delete or disable a PostgreSQL Pipeline, Hevo automatically drops the replication slot created for that Pipeline. Hevo also drops the replication slot if the Pipeline is disabled due to the WAL size exceeding the configured threshold value ( % ). However, sometimes, Hevo may not be able to drop the replication slot automatically. In both scenarios, Hevo sends alert notifications on the dashboard and over email only if you have set your Email Preferences to receive the Replication Slot not Dropped critical alert.
The email content differs depending on whether Hevo was able to drop the replication slot automatically or not. Refer to the sections below for the details.
The replication slot is dropped successfully
Depending on the action initiated, Hevo deletes or disables the Pipeline and drops the replication slot automatically. The email alert notification sent is structured as follows:
| Section Heading | Description |
|---|---|
| Subject | Pipeline disabled/deleted and the replication slot dropped |
| What has happened? | This section contains the following information: - The action that was taken, such as disabling the Pipeline, and by which team member. - The name of the Pipeline that was deleted/disabled. - The name of the Source and Destination configured in the Pipeline. |
| Impact | The section contains the effect of the action taken. For example, data replication is stopped. |
| Recommendation | This section is present when a Pipeline is disabled, and the recommendation could be to: - Enable the Pipeline if it was disabled by another user. - Increase the WAL size threshold value for the Pipeline if it was disabled by Hevo. |
| Contact us | This section contains a link to contact Hevo Support if required. |
The replication slot was not dropped
Sometimes, Hevo is unable to drop the replication slot automatically when deleting or disabling the Pipeline. The email sent in that scenario is structured as follows:
| Section Heading | Description |
|---|---|
| Subject | Hevo encountered an issue while deleting/disabling Pipeline |
| What has happened? | This section contains the following information: - The name of the Pipeline that was deleted/disabled. - The name of the Source and Destination configured in the Pipeline. - The status of the action. |
| Impact | The section contains the effect of the action taken. In this case, the replication slot drop failure could result in the accumulation of unnecessary WAL segments, which may affect the WAL size. |
| Recommendation | This section contains the name of the replication slot that needs to be dropped. If the Pipeline was disabled, this section also includes the subsequent action. |
| Contact us | This section contains a link to contact Hevo Support if required. |
Dropping a Replication Slot
Perform the following steps if you want to drop a replication slot manually:
-
Connect to the PostgreSQL database configured in your Pipeline as a Superuser using an SQL client tool, such as psql.
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Run the following command to drop the slot:
SELECT pg_drop_replication_slot('<slot_name>');Replace the placeholder value in the command above with the slot name displayed on the Edge Alerts dashboard. For example, <slot_name> with hevo_1731663131274.