@Rocky Before downgrading a shared-data cluster 4.0.13 to 3.5.14, should

SET GLOBAL enable_rewrite_simple_agg_to_meta_scan=false;

be set ?

Based on the StarRocks documentation and release notes for version 4.0 and 3.5: No, it is likely not required to set

enable_rewrite_simple_agg_to_meta_scan=false

when downgrading to v3.5.14, but it was mandatory for earlier versions of the 3.5.x branch. Analysis * The Warning Range: The official Downgrade Notes for StarRocks 4.0 specify that this command must be executed when downgrading from v4.0.x to the specific range of v3.5.2 to v3.5.10. * Version v3.5.11 Change: In version 3.5.11, the feature

rewrite_simple_agg_to_meta_scan

was improved and enabled by default. Since your target version (3.5.14) is newer than 3.5.10, it includes the fixes that made the metadata compatible, which is why it is excluded from the warning range. * General Shared-data Caution: While this specific variable might not be required for 3.5.14, always ensure you follow these standard downgrade precautions for shared-data clusters: 1. Do not downgrade to v3.5.0 or v3.5.1: This will cause metadata incompatibility and FE crashes. Downgrading to v3.5.14 is safe in this regard. 2. Metadata Backup: Always create a metadata snapshot using

ALTER SYSTEM CREATE IMAGE

before starting the downgrade process. 3. Disable Tablet Balancing: It is recommended to disable the balancer and tablet scheduling before downgrading to prevent inconsistencies during the node restart process:

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

Summary Since you are targeting v3.5.14, you do not need to set

enable_rewrite_simple_agg_to_meta_scan=false

. The requirement was specifically for destination versions between 3.5.2 and 3.5.10. References • release_notes/release-4.0.md • release_notes/release-3.5.md