With REORG TABLE ... APPLY (PURGE), Delta rewrites files so that rows marked as deleted by deletion vectors are actually removed from storage, which is usually done before running VACUUM.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains REORG TABLE in context, with comparison tables and the common traps.
Terms in this definition
- APPLY
Evaluates a table-valued expression for every row on its left, inside
FROM. Think ofOUTER APPLYas a left outer join andCROSS APPLYas an inner join. - Deletion vectors
Lets Delta Lake and Iceberg tables flag removed or changed rows through metadata rather than rewriting complete Parquet files, a soft delete that speeds up deletes, updates and merges. The physical rewrite happens later, when
OPTIMIZEor aREORG TABLEpurge runs. - General-purpose v1
The older storage account kind (
Storage), which lacks access tiers, Archive and premium file shares and retires on 13 October 2026. Converting to ZRS requires first upgrading to GPv2, a one-way change. - VACUUM
Removes data files that a table no longer references once they are older than the retention period, 7 days unless changed. Versions older than that can no longer be reached with time travel.