Advanced configurations for CDC using Logical Replication

YB-TServer flags

You can use the following YB-TServer flags to tune logical replication deployment configuration:

• ysql_yb_default_replica_identity
• cdcsdk_enable_dynamic_table_support
• cdcsdk_publication_list_refresh_interval_secs
• cdcsdk_max_consistent_records
• cdcsdk_vwal_getchanges_resp_max_size_bytes

Retention of resources

CDC retains resources (such as WAL segments) that contain information related to the changes involved in the transactions. These resources are typically retained until the consuming client acknowledges the receipt of all the transactions contained in that resource.

Retaining resources has an impact on the system. Clients are expected to consume these transactions within configurable duration limits. Resources will be released if the duration exceeds these configured limits.

Use the following flags to control the duration for which resources are retained:

• cdc_wal_retention_secs
• cdc_intent_retention_ms

Resources are retained for each tablet of a table that is part of a database whose changes are being consumed using a replication slot. This includes those tables that may not be currently part of the publication specification.