in TxnUtils.needNewQuery() "sizeInBytes / 1024 > queryMemoryLimit" doesn't do the right thing.
If the user sets METASTORE_DIRECT_SQL_MAX_QUERY_LENGTH to 1K, they most likely want each SQL string to be at most 1K.
But if sizeInBytes=2047, this still returns false.
It should include length of "suffix" in computation of sizeInBytes
Along the same lines: the check for max query length is done after each batch is already added to the query. Suppose there are 1000 9-digit txn IDs in each IN(...). That's, conservatively, 18KB of text. So the length of each query is increasing in 18KB chunks.
I think the check for query length should be done for each item in IN clause.
If some DB has a limit on query length of X, then any query > X will fail. So I think this must ensure not to produce any queries > X, even by 1 char.
For example, case 3.1 of the UT generates a query of almost 4000 characters - this is clearly > 1KB.