v.23.8Improvement
Add SYSTEM SYNC FILESYSTEM CACHE Command for State Comparison and Fixing in ClickHouse
Add SYSTEM SYNC FILESYSTEM CACHE command. It will compare in-memory state of filesystem cache with what it has on disk and fix in-memory state if needed. This is only needed if you are making manual interventions in on-disk data, which is highly discouraged. #51622 (Kseniia Sumarokova).Why it matters
This feature addresses inconsistencies between the in-memory filesystem cache and the actual data stored on disk that may occur due to manual interventions in on-disk data. It helps ensure data integrity by correcting the in-memory state to match the disk state, which is critical when manual modifications are made, although such interventions are generally discouraged.How to use it
Execute the command:SYSTEM SYNC FILESYSTEM CACHEThis command compares the current in-memory filesystem cache with the on-disk data and fixes any discrepancies to bring the cache in sync. It should be used only if manual changes to on-disk data were made.