[IMPALA-5572] Support timestamp codegen for text scanner

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Impala 2.10.0
• Fix Version/s: Impala 2.10.0
• Component/s: Backend
• Labels: codegen performance
• Target Version: Product Backlog
• Epic Color: ghx-label-2
• Assignee: Tianyi Wang
• Reporter: Tim Armstrong
• Created: 23/Jun/17 18:24
• Updated: 07/Feb/23 11:13
• Resolved: 08/Aug/17 17:10

Description

Codegen is disabled when scanning text tables with timestamp columns. The message is "Timestamp not yet supported for codegen."

The supported types use cross-compiled conversion functions in TextConverter::CodegenWriteSlot():

    IRFunction::Type parse_fn_enum;
    Function* parse_fn = NULL;
    switch (slot_desc->type().type) {
      case TYPE_BOOLEAN:
        parse_fn_enum = IRFunction::STRING_TO_BOOL;
        break;
      case TYPE_TINYINT:
        parse_fn_enum = IRFunction::STRING_TO_INT8;
        break;
      case TYPE_SMALLINT:
        parse_fn_enum = IRFunction::STRING_TO_INT16;
        break;
      case TYPE_INT:
        parse_fn_enum = IRFunction::STRING_TO_INT32;
        break;
      case TYPE_BIGINT:
        parse_fn_enum = IRFunction::STRING_TO_INT64;
        break;
      case TYPE_FLOAT:
        parse_fn_enum = IRFunction::STRING_TO_FLOAT;
        break;
      case TYPE_DOUBLE:
        parse_fn_enum = IRFunction::STRING_TO_DOUBLE;
        break;
      default:
        DCHECK(false);
        return NULL;
    }

TimestampValue::Parse() does not implement the same interface as the other functions but I think we could either change the interface or cross-compile an adapter function.