For a downgrade from v4.0.13 to v3.5.14, you do not need to set

enable_rewrite_simple_agg_to_meta_scan=false

. Based on the StarRocks release notes and downgrade documentation, here is the breakdown: * Version Range for the Setting: The requirement to execute

SET GLOBAL enable_rewrite_simple_agg_to_meta_scan=false;

specifically applies when downgrading to the version range v3.5.2 through v3.5.10. * Why it's not needed for v3.5.14: Starting from v3.5.11, the system variable

enable_rewrite_simple_agg_to_meta_scan

was enabled by default and the underlying feature is fully supported. Since your target version (3.5.14) is later than 3.5.11, it recognizes this setting and the associated metadata, making the manual disablement unnecessary. * Strict Prohibitions: Ensure you do not downgrade to v3.5.0 or v3.5.1, as these versions have known metadata incompatibilities with v4.0 that will cause an FE crash. Downgrading to v3.5.2 or later (including your target v3.5.14) is the supported path. General Downgrade Precautions Even though that specific variable is not required for your target version, remember the standard downgrade procedure: 1. Disable Tablet Balancing: Before starting, disable the balancer to prevent data movement issues during the transition:

sql
    ADMIN SET FRONTEND CONFIG ("disable_balance" = "true");
    ADMIN SET FRONTEND CONFIG ("disable_colocate_balance" = "true");

2. Order of Operations: Always downgrade FEs first (Followers then Leader) and then the BEs. 3. Metadata Snapshot: It is highly recommended to create a metadata image/snapshot (

ALTER SYSTEM CREATE IMAGE

) before beginning the downgrade process. For more details, you can refer to the StarRocks v4.0 Release Notes and the Downgrade Guide. References • sql-reference/System_variable.md • using_starrocks/async_mv/use_cases/query_rewrite_with_materialized_views.md • administration/management/FE_configuration.md