[HIVE-15267] Make query length calculation logic more accurate in TxnUtils.needNewQuery()

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2.1, 2.1.0
• Fix Version/s: 3.0.0
• Component/s: Hive, Transactions
• Target Version/s: 1.3.0, 3.0.0
• Assignee: Steve Yeom
• Reporter: Wei Zheng
• Created: 22/Nov/16 21:15
• Updated: 22/May/18 23:58
• Resolved: 13/Oct/17 15:45

Description

In HIVE-15181 there's such review comment, for which this ticket will handle

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.

Issue Links

• relates to: HIVE-15181 buildQueryWithINClause didn't properly handle multiples of ConfVars.METASTORE_DIRECT_SQL_MAX_ELEMENTS_IN_CLAUSE
• links to: Review Board