Customization for created replication slot

[zxqfd555]

Hello!
Thank you for your work on this library — it’s really helpful.

I’ve encountered a limitation when using it for exporting a table from PostgreSQL to an external storage.

My use case is the following:

1. Read the initial consistent snapshot of a table.
2. Then continue consuming WAL using the library.
3. The process may terminate at any arbitrary moment, after which replication is no longer needed.
4. Therefore, the replication slot should be temporary.

What I would like to do on the PostgreSQL side is something like:

CREATE_REPLICATION_SLOT {replication_slot_name} TEMPORARY LOGICAL pgoutput EXPORT_SNAPSHOT;

This allows me to:

• Create a temporary logical replication slot.
• Obtain the exported snapshot.
• Read the initial state of the table.
• Then continue streaming changes from WAL once the snapshot is consumed.

However, I ran into the following limitation:

• I cannot create a temporary replication slot using LogicalReplicationStream, which I need to use for streaming.
• The slot created internally by LogicalReplicationStream is not temporary, so it remains after the application terminates.
• I could create a slot manually using PgReplicationConnection, but in the case of a temporary slot, it is dropped when the connection is closed.
• Creating it on one connection and using it from LogicalReplicationStream is not possible either, because a replication slot can only be used by a single backend.

Proposal

Please consider adding support for configuring replication slot parameters in LogicalReplicationStream, so that the created slot can be customized in the same way as it's done in create_replication_slot_with_options in PgReplicationConnection.

For example, allowing something like:

• Passing slot creation options into the constructor/builder.
• Or exposing slot creation configuration explicitly.

This would make it possible to use temporary logical replication slots in a clean and safe way.

Additionally, I would appreciate any suggested workaround that does not require significant refactoring, at least until such a feature is available.

Thank you!

[isdaniel]

Hi @zxqfd555 thank you for your feedback. I had made a PR #23 from my understanding of your request.

new code can setup slot option via with_slot_options after initial stream config, I think that would satisfy your requirement.

let config = ReplicationStreamConfig::new(
        "my_slot".to_string(),           // Replication slot name
        "my_publication".to_string(),     // Publication name
        2,                                // Protocol version
        StreamingMode::On,                // Streaming mode
        Duration::from_secs(10),          // Feedback interval
        Duration::from_secs(30),          // Connection timeout
        Duration::from_secs(60),          // Health check interval
        RetryConfig::default(),           // Retry configuration
    )
    // Optional: configure slot creation options
    .with_slot_options(ReplicationSlotOptions {
        temporary: true,
        snapshot: Some("export".to_string()),
        ..Default::default()
    });

because this week is lunar new year, therefore I would delay reply and don't have too much time to test the PR, if you are urgent to use, please feel free to pull the PR branch and check it out, and you can leave any commnetI will check it later.

[zxqfd555]

Thank you for the quick response!
Yes, this variant will make it possible to use the library for my case.

[isdaniel]

release #24