353 lines
13 KiB
C++
353 lines
13 KiB
C++
/**
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* Copyright (c) 2021 OceanBase
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* OceanBase CE is licensed under Mulan PubL v2.
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* You can use this software according to the terms and conditions of the Mulan PubL v2.
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* You may obtain a copy of Mulan PubL v2 at:
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* http://license.coscl.org.cn/MulanPubL-2.0
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* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
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* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
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* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
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* See the Mulan PubL v2 for more details.
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*/
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#define USING_LOG_PREFIX SQL_ENG
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#include "sql/engine/expr/ob_expr_case.h"
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#include "sql/engine/expr/ob_expr_operator.h"
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//#include "sql/engine/expr/ob_expr_promotion_util.h"
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#include "sql/session/ob_sql_session_info.h"
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#include "sql/engine/ob_exec_context.h"
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namespace oceanbase
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{
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using namespace common;
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namespace sql
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{
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typedef int (*CheckIsMatchFunc)(const ObDatum *when_datum, bool &match_when);
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ObExprCase::ObExprCase(ObIAllocator &alloc)
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: ObExprOperator(alloc, T_OP_CASE, N_CASE, MORE_THAN_ONE, VALID_FOR_GENERATED_COL, NOT_ROW_DIMENSION)
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{
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disable_operand_auto_cast();
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param_lazy_eval_ = true;
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}
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ObExprCase::~ObExprCase()
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{
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}
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/*
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* NOTE：calc_result_typeN中param_num只涵盖了then/else表达式，未涵盖when表达式
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*/
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int ObExprCase::calc_result_typeN(ObExprResType &type,
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ObExprResType *types_stack,
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int64_t param_num,
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ObExprTypeCtx &type_ctx) const
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{
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// case
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// when 10 then expr1
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// when 11 then expr2
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// [else expr3]
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int ret = OB_SUCCESS;
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if (OB_ISNULL(types_stack)) {
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LOG_WARN("null types");
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ret = OB_INVALID_ARGUMENT;
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} else if (OB_UNLIKELY(param_num < 3 || param_num % 2 == 0)) {
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ret = OB_INVALID_ARGUMENT;
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LOG_WARN("param num is not correct", K(param_num));
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} else { //param_num >=3 and param_num is odd
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/* in order to be compatible with mysql
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* both in ob_expr_case.cpp and ob_expr_arg_case.cpp
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* types_stack includes the condition exprs.
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* In expr_case, there is no arg param expr compared with expr_arg_case
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*/
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const int64_t cond_type_count = param_num / 2;
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const int64_t val_type_count = param_num - cond_type_count;
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const ObLengthSemantics default_length_semantics = (OB_NOT_NULL(type_ctx.get_session()) ? type_ctx.get_session()->get_actual_nls_length_semantics() : LS_BYTE);
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if (OB_FAIL(aggregate_result_type_for_case(
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type,
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types_stack + cond_type_count,
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val_type_count,
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type_ctx.get_coll_type(),
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lib::is_oracle_mode(),
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default_length_semantics,
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type_ctx.get_session(),
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true, false,
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is_called_in_sql_))) {
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LOG_WARN("failed to aggregate result type");
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} else {
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ObExprOperator::calc_result_flagN(type, types_stack + cond_type_count, val_type_count);
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}
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if (OB_SUCC(ret)) {
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for (int64_t i = 0; i < cond_type_count; ++i) {
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const ObObjType cond_type = types_stack[i].get_type();
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const ObObjTypeClass cond_tc = ob_obj_type_class(cond_type);
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if (ObIntTC == cond_tc || ObUIntTC == cond_tc || ObNumberTC == cond_tc ||
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ObNullTC == cond_tc) {
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types_stack[i].set_calc_type(cond_type);
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types_stack[i].set_calc_collation(types_stack[i]);
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} else {
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types_stack[i].set_calc_type(ObDoubleType);
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types_stack[i].set_calc_collation_type(CS_TYPE_BINARY);
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types_stack[i].set_calc_collation_level(CS_LEVEL_NUMERIC);
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}
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}
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bool is_expr_integer_type = (ob_is_int_tc(type.get_type()) ||
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ob_is_uint_tc(type.get_type()));
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for (int64_t i = cond_type_count; OB_SUCC(ret) && i < param_num; ++i) {
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bool is_arg_integer_type = (ob_is_int_tc(types_stack[i].get_type()) ||
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ob_is_uint_tc(types_stack[i].get_type()));
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if ((is_arg_integer_type && is_expr_integer_type) ||
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ObNullType == types_stack[i].get_type()) {
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// see ObExprCoalesce::calc_result_typeN
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types_stack[i].set_calc_meta(types_stack[i].get_obj_meta());
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} else {
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types_stack[i].set_calc_meta(type.get_obj_meta());
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}
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}
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}
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}
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return ret;
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}
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int ObExprCase::cg_expr(ObExprCGCtx &op_cg_ctx,
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const ObRawExpr &raw_expr,
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ObExpr &rt_expr) const
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{
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int ret = OB_SUCCESS;
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UNUSED(op_cg_ctx);
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const ObCaseOpRawExpr &case_expr = dynamic_cast<const ObCaseOpRawExpr&>(raw_expr);
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// 新引擎下case表达式when expr一定要返回int/null，即when expr一定是布尔语义的表达式
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for (int64_t i = 0; OB_SUCC(ret) && i < case_expr.get_when_expr_size(); ++i) {
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const ObRawExpr *when_expr = case_expr.get_when_param_expr(i);
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const ObObjType &when_expr_res_type = when_expr->get_result_type().get_type();
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if (OB_UNLIKELY(ObNullType != when_expr_res_type &&
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!ob_is_integer_type(when_expr_res_type))) {
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ret = OB_ERR_UNEXPECTED;
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LOG_WARN("when expr must return integer", K(ret), K(when_expr_res_type));
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}
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}
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if (OB_SUCC(ret)) {
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rt_expr.eval_func_ = calc_case_expr;
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rt_expr.eval_batch_func_ = eval_case_batch;
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}
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return ret;
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}
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static int check_is_match(const ObDatum &when_datum, bool &match_when)
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{
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int ret = OB_SUCCESS;
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if (when_datum.is_null()) {
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match_when = false;
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} else {
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int64_t v = when_datum.get_int();
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match_when = (v != 0) ? true : false;
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}
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return ret;
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}
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int ObExprCase::calc_case_expr(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res_datum)
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{
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int ret = OB_SUCCESS;
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const bool has_else = (expr.arg_cnt_ % 2 != 0);
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int64_t loop = (has_else) ? expr.arg_cnt_ - 1 : expr.arg_cnt_;
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bool match_when = false;
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ObDatum *when_datum = NULL;
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ObDatum *then_datum = NULL;
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bool has_result = false;
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int64_t expr_idx = 0;
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for ( ; OB_SUCC(ret) && !match_when && expr_idx < loop; expr_idx += 2) {
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if (OB_FAIL(expr.args_[expr_idx]->eval(ctx, when_datum))) {
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LOG_WARN("eval when expr failed", K(ret), K(expr_idx));
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} else if (OB_FAIL(check_is_match(*when_datum, match_when))) {
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LOG_WARN("check is when expr match failed", K(ret), K(expr_idx));
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} else if (match_when) {
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if (OB_FAIL(expr.args_[expr_idx+1]->eval(ctx, then_datum))) {
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LOG_WARN("eval then expr failed", K(ret), K(expr_idx+1));
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} else {
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has_result = true;
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}
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}
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}
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if (OB_SUCC(ret)) {
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if (!match_when) {
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if (has_else) {
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if (OB_FAIL(expr.args_[expr.arg_cnt_-1]->eval(ctx, then_datum))) {
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LOG_WARN("eval else expr failed for case when", K(ret));
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} else {
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has_result = true;
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}
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}
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}
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}
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if (OB_SUCC(ret)) {
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if (!has_result) {
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res_datum.set_null();
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} else {
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if (OB_ISNULL(then_datum)) {
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ret = OB_ERR_UNEXPECTED;
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LOG_WARN("then_datum is NULL", K(ret));
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} else {
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res_datum.set_datum(*then_datum);
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}
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}
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}
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return ret;
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}
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// Oracle模式下，在deduce type阶段需要将when/then expr类型要一致
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int ObExprCase::is_same_kind_type_for_case(const ObIArray<ObExprResType> &type_arr)
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{
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int ret = OB_SUCCESS;
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if (OB_SUCC(ret)) {
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bool match = false;
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int64_t first_not_null_idx = OB_INVALID_ID;
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for (int64_t i = 0; OB_SUCC(ret) &&
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OB_INVALID_ID == first_not_null_idx && i < type_arr.count(); ++i) {
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if (!ob_is_null(type_arr.at(i).get_type())) {
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first_not_null_idx = i;
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}
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}
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first_not_null_idx = OB_INVALID_ID == first_not_null_idx ? 0 : first_not_null_idx;
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const ObExprResType &res_type = type_arr.at(first_not_null_idx);
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for (int64_t i = first_not_null_idx+1; OB_SUCC(ret) && i < type_arr.count(); ++i) {
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if (OB_FAIL(ObExprOperator::is_same_kind_type_for_case(res_type,
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type_arr.at(i), match))) {
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LOG_WARN("fail to judge same type", K(i), K(res_type), K(type_arr.at(i)), K(ret));
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} else if (!match) {
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ret = OB_ERR_INVALID_TYPE_FOR_OP;
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LOG_WARN("fail to judge same type", K(i), K(res_type), K(type_arr.at(i)), K(ret));
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}
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}
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}
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return ret;
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}
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int ObExprCase::eval_case_batch(const ObExpr &expr,
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ObEvalCtx &ctx,
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const ObBitVector &skip,
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const int64_t batch_size)
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{
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int ret = OB_SUCCESS;
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const bool has_else = (expr.arg_cnt_ % 2 != 0);
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int64_t loop = (has_else) ? expr.arg_cnt_ - 1 : expr.arg_cnt_;
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bool match_when = false;
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ObDatum *results = expr.locate_batch_datums(ctx);
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LOG_DEBUG("eval_case_batch", K(expr.arg_cnt_));
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if (OB_ISNULL(results)) {
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ret = OB_ERR_UNEXPECTED;
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LOG_WARN("results frame is not init", K(ret));
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} else {
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ObBitVector &eval_flags = expr.get_evaluated_flags(ctx);
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ObBitVector *case_when_match = nullptr;
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ObBitVector *case_not_match = nullptr;
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void * data = nullptr;
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void * data1 = nullptr;
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ObEvalCtx::TempAllocGuard alloc_guard(ctx);
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if (OB_ISNULL(data = alloc_guard.get_allocator().alloc(ObBitVector::memory_size(batch_size)))) {
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ret = OB_ALLOCATE_MEMORY_FAILED;
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LOG_WARN("failed to alloc memory for case_when_match", K(ret));
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} else if (OB_ISNULL(data1 = alloc_guard.get_allocator().alloc(ObBitVector::memory_size(batch_size)))) {
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ret = OB_ALLOCATE_MEMORY_FAILED;
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LOG_WARN("failed to alloc memory for case_when_match", K(ret));
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} else {
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case_when_match = to_bit_vector(data);
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case_not_match = to_bit_vector(data1);
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case_when_match->reset(batch_size);
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case_not_match->reset(batch_size);
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//case_when_match = eval_flags | skip
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case_when_match->bit_calculate(skip, eval_flags, batch_size,
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[](const uint64_t l, const uint64_t r) { return (l | r); });
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case_not_match->bit_calculate(skip, eval_flags, batch_size,
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[](const uint64_t l, const uint64_t r) { return (l | r); });
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}
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// E.G
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// SELECT CASE WHEN expr1 THEN expr2 WHEN expr3 THEN expr4 ... ELSE exprN END
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// the logic is
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// 1. calc when branch, save result in when_datums and use match_when flag
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// to mark which rows are matched in when branch and these rows should be
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// calculated in then branch
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// 2. calc then branch, put matching result(then_datums) into output datums
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// (results)
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// REPEAT 1. and 2.
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// ...
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// LAST.
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// calc else branch and put matching result(then_datums) into output datums
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for (int64_t expr_idx = 0; OB_SUCC(ret) && expr_idx < loop; expr_idx += 2) {
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if (OB_FAIL(expr.args_[expr_idx]->eval_batch(ctx, *case_when_match, batch_size))) {
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LOG_WARN("failed to eval batch", K(ret), K(expr_idx));
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} else {
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ObDatumVector when_datums = expr.args_[expr_idx]->locate_expr_datumvector(ctx);
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//first eval when datums
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for (int64_t j = 0; OB_SUCC(ret) && j < batch_size; ++j) {
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if (case_when_match->at(j)) {
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continue;
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}
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if (OB_FAIL(check_is_match(*when_datums.at(j), match_when))) {
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LOG_WARN("check is when expr match failed", K(ret), K(j));
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} else if (match_when) {
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case_when_match->set(j);
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} else {
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// not match, mark case_not_match to stop calculating then branch
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case_not_match->set(j);
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}
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}
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//now eval then datums
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if (OB_FAIL(ret)) {
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} else if (OB_FAIL(expr.args_[expr_idx + 1]->eval_batch(ctx, *case_not_match, batch_size))) {
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LOG_WARN("failed to eval batch", K(ret), K(expr_idx + 1));
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} else {
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ObDatumVector then_datums = expr.args_[expr_idx + 1]->locate_expr_datumvector(ctx);
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for (int64_t j = 0; OB_SUCC(ret) && j < batch_size; ++j) {
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if (case_not_match->at(j)) {
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continue;
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}
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results[j].set_datum(*then_datums.at(j));
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eval_flags.set(j);
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}
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// rows matched in this round should not match in next round, therefor,
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// copy last round matched rows flag(case_when_match) into case_not_match
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case_not_match->deep_copy(*case_when_match, batch_size);
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}
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}
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}
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//now set the result of the rest, skip rows already matched (case_when_match)
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if (OB_SUCC(ret)) {
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if (has_else) {
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if (OB_FAIL(expr.args_[expr.arg_cnt_ - 1]->eval_batch(ctx, *case_when_match, batch_size))) {
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LOG_WARN("failed to eval batch", K(ret));
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} else {
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ObDatumVector else_datums = expr.args_[expr.arg_cnt_ - 1]->locate_expr_datumvector(ctx);
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for (int64_t j = 0; OB_SUCC(ret) && j < batch_size; ++j) {
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if (case_when_match->at(j)) {
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continue;
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}
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results[j].set_datum(*else_datums.at(j));
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eval_flags.set(j);
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}
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}
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} else {
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for (int64_t j = 0; OB_SUCC(ret) && j < batch_size; ++j) {
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if (case_when_match->at(j)) {
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continue;
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}
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results[j].set_null();
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eval_flags.set(j);
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}
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}
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}
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}
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return ret;
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}
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}
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}
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