Definition
Controls how def~tables are exposed to queriesGiven such flexible and comprehensive layout of data and rich def~timeline, Hudi is able to support three different ways of querying a def~table, depending on its def~table-typeQuery Type def~copy-on-write (COW) def~merge-on-read (MOR) Snapshot Query Query is performed on the latest def~base-files across all def~file-slices in a given def~table or def~table-partition and will see records written upto the latest def~commit action. Query is performed by merging the latest def~base-file and its def~log-files across all def~file-slices in a given def~table or def~table-partition and will see records written upto the latest def~delta-commit action. Incremental Query Query is performed on the latest def~base-file, within a given range of start , end def~instant-times (called the incremental query window), while fetching only records that were written during this window by use of the def~hoodie-special-columns Query is performed on a latest def~file-slice within the incremental query window, using a combination of reading records out of base or log blocks, depending on the window itself. Read Optimized Query Same as snapshot query Only access the def~base-file, providing data as of the last def~compaction action performed on a given def~file-slice. In general, guarantees of how fresh/upto date the queried data is, depends on def~compaction-policy 
Related concepts
- def~read-optimized-query
- def~incremental-query
- def~snapshot-query
- def~timeline
- def~table
- def~commit
- def~table-type