Gopal V created HIVE-20890:

             Summary: ACID: Allow whole table ReadLocks to skip all partition 
                 Key: HIVE-20890
             Project: Hive
          Issue Type: Bug
          Components: Transactions
            Reporter: Gopal V

HIVE-19369 proposes adding a EXCL_WRITE lock which does not wait for any 
SHARED_READ locks for insert operations - in the presence of that lock, the 
insert overwrite no longer takes an exclusive lock.

The only exclusive operation will be a schema change or drop table, which 
should take an exclusive lock on the entire table directly.

explain locks select * from tpcds_bin_partitioned_orc_1000.store_sales where 

|                      Explain                       |
| LOCK INFORMATION:                                  |
| tpcds_bin_partitioned_orc_1000.store_sales -> SHARED_READ |
| tpcds_bin_partitioned_orc_1000.store_sales.ss_sold_date_sk=2452626 -> 

So the per-partition SHARED_READ locks are no longer necessary, if the lock 
builder already includes the table-wide SHARED_READ locks.

The removal of entire partitions is the only part which needs to be taken care 
of within this semantics as row-removal instead of directory removal (i.e "drop 
partition" -> "truncate partition" and have the truncation trigger a whole 
directory cleaner, so that the partition disappears when there are 0 rows left).

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