Fix getTables(types=[]) returning rows in Thrift mode#1451
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Per JDBC spec, an empty `types` array passed to DatabaseMetaData.getTables() means "no types selected" and should return zero rows. The Thrift path was leaking rows because the client-side filter at MetadataResultSetBuilder.getTablesResult() is guarded by `tableTypes.length > 0`, which short-circuits the filter for empty arrays — letting all rows from the server pass through. This was visible for legacy hive_metastore objects, whose TABLE_TYPE the Thrift server returns as an empty string. The client normalizes "" → "TABLE", and with the broken filter guard those rows survived. Fix: mirror SEA's existing guard (DatabricksMetadataQueryClient.java:128-131) in the Thrift path — short-circuit to an empty result set at the top of listTables when tableTypes is non-null and length 0. The server is never queried. Co-authored-by: Isaac Signed-off-by: Sreekanth Vadigi <sreekanth.vadigi@databricks.com>
gopalldb
approved these changes
May 18, 2026
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Summary
DatabaseMetaData.getTables(_, _, _, new String[0])(emptytypesarray) means "no types selected" and should return zero rows. The Thrift path was leaking rows because the post-server filter atMetadataResultSetBuilder.getTablesResultis guarded bytableTypes.length > 0, which short-circuits the filter for empty arrays.hive_metastoreobjects haveTABLE_TYPE=""from the Thrift server. The client normalizes""→"TABLE", and with the broken filter guard those rows survived even fortypes=[].DatabricksMetadataQueryClient.java:128-131) in the ThriftlistTables— short-circuit to an empty result set at the top of the method whentableTypesis non-null and length 0. The server is never queried.Test plan
testListTablesWithEmptyTypesReturnsEmptyWithoutServerCall— asserts zero rows AND thatthriftAccessor.getThriftResponseis never invokedtestListTables(non-empty types) still passes — 46/46 inDatabricksThriftServiceClientTestgetTables(null, null, null, [])on Thrift returned 2hive_metastore.default.trim_repro*rows while SEA returned 0; after fix, both return 0This pull request and its description were written by Isaac.