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Copy pathob_expr_case.cpp
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356 lines (336 loc) · 13.2 KB
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/**
* Copyright (c) 2021 OceanBase
* OceanBase CE is licensed under Mulan PubL v2.
* You can use this software according to the terms and conditions of the Mulan PubL v2.
* You may obtain a copy of Mulan PubL v2 at:
* http://license.coscl.org.cn/MulanPubL-2.0
* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
* See the Mulan PubL v2 for more details.
*/
#define USING_LOG_PREFIX SQL_ENG
#include "sql/engine/expr/ob_expr_case.h"
#include "sql/engine/expr/ob_expr_operator.h"
//#include "sql/engine/expr/ob_expr_promotion_util.h"
#include "sql/session/ob_sql_session_info.h"
#include "sql/engine/ob_exec_context.h"
namespace oceanbase
{
using namespace common;
namespace sql
{
typedef int (*CheckIsMatchFunc)(const ObDatum *when_datum, bool &match_when);
ObExprCase::ObExprCase(ObIAllocator &alloc)
: ObExprOperator(alloc, T_OP_CASE, N_CASE, MORE_THAN_ONE, VALID_FOR_GENERATED_COL, NOT_ROW_DIMENSION)
{
disable_operand_auto_cast();
param_lazy_eval_ = true;
}
ObExprCase::~ObExprCase()
{
}
/*
* NOTE：calc_result_typeN中param_num只涵盖了then/else表达式，未涵盖when表达式
*/
int ObExprCase::calc_result_typeN(ObExprResType &type,
ObExprResType *types_stack,
int64_t param_num,
ObExprTypeCtx &type_ctx) const
{
// case
// when 10 then expr1
// when 11 then expr2
// [else expr3]
int ret = OB_SUCCESS;
if (OB_ISNULL(types_stack)) {
LOG_WARN("null types");
ret = OB_INVALID_ARGUMENT;
} else if (OB_UNLIKELY(param_num < 3 || param_num % 2 == 0)) {
ret = OB_INVALID_ARGUMENT;
LOG_WARN("param num is not correct", K(param_num));
} else { //param_num >=3 and param_num is odd
/* in order to be compatible with mysql
* both in ob_expr_case.cpp and ob_expr_arg_case.cpp
* types_stack includes the condition exprs.
* In expr_case, there is no arg param expr compared with expr_arg_case
*/
const int64_t cond_type_count = param_num / 2;
const int64_t val_type_count = param_num - cond_type_count;
const ObLengthSemantics default_length_semantics = (OB_NOT_NULL(type_ctx.get_session()) ? type_ctx.get_session()->get_actual_nls_length_semantics() : LS_BYTE);
if (OB_FAIL(aggregate_result_type_for_case(
type,
types_stack + cond_type_count,
val_type_count,
type_ctx.get_coll_type(),
lib::is_oracle_mode(),
default_length_semantics,
type_ctx.get_session(),
true, false,
is_called_in_sql_))) {
LOG_WARN("failed to aggregate result type");
} else {
ObExprOperator::calc_result_flagN(type, types_stack + cond_type_count, val_type_count);
}
if (OB_SUCC(ret)) {
for (int64_t i = 0; i < cond_type_count; ++i) {
const ObObjType cond_type = types_stack[i].get_type();
const ObObjTypeClass cond_tc = ob_obj_type_class(cond_type);
if (ObIntTC == cond_tc || ObUIntTC == cond_tc
|| ObNumberTC == cond_tc || ObDecimalIntTC == cond_tc
|| ObNullTC == cond_tc) {
types_stack[i].set_calc_type(cond_type);
types_stack[i].set_calc_collation(types_stack[i]);
} else {
types_stack[i].set_calc_type(ObDoubleType);
types_stack[i].set_calc_collation_type(CS_TYPE_BINARY);
types_stack[i].set_calc_collation_level(CS_LEVEL_NUMERIC);
}
}
bool is_expr_integer_type = (ob_is_int_tc(type.get_type()) ||
ob_is_uint_tc(type.get_type()));
for (int64_t i = cond_type_count; OB_SUCC(ret) && i < param_num; ++i) {
bool is_arg_integer_type = (ob_is_int_tc(types_stack[i].get_type()) ||
ob_is_uint_tc(types_stack[i].get_type()));
if ((is_arg_integer_type && is_expr_integer_type) ||
ObNullType == types_stack[i].get_type()) {
// see ObExprCoalesce::calc_result_typeN
types_stack[i].set_calc_meta(types_stack[i].get_obj_meta());
} else {
types_stack[i].set_calc_meta(type.get_obj_meta());
if (ObDecimalIntType == type.get_obj_meta().get_type()) {
types_stack[i].set_calc_accuracy(type.get_accuracy());
}
}
}
}
}
return ret;
}
int ObExprCase::cg_expr(ObExprCGCtx &op_cg_ctx,
const ObRawExpr &raw_expr,
ObExpr &rt_expr) const
{
int ret = OB_SUCCESS;
UNUSED(op_cg_ctx);
const ObCaseOpRawExpr &case_expr = dynamic_cast<const ObCaseOpRawExpr&>(raw_expr);
// 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
for (int64_t i = 0; OB_SUCC(ret) && i < case_expr.get_when_expr_size(); ++i) {
const ObRawExpr *when_expr = case_expr.get_when_param_expr(i);
const ObObjType &when_expr_res_type = when_expr->get_result_type().get_type();
if (OB_UNLIKELY(ObNullType != when_expr_res_type &&
!ob_is_integer_type(when_expr_res_type))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("when expr must return integer", K(ret), K(when_expr_res_type));
}
}
if (OB_SUCC(ret)) {
rt_expr.eval_func_ = calc_case_expr;
rt_expr.eval_batch_func_ = eval_case_batch;
}
return ret;
}
static int check_is_match(const ObDatum &when_datum, bool &match_when)
{
int ret = OB_SUCCESS;
if (when_datum.is_null()) {
match_when = false;
} else {
int64_t v = when_datum.get_int();
match_when = (v != 0) ? true : false;
}
return ret;
}
int ObExprCase::calc_case_expr(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res_datum)
{
int ret = OB_SUCCESS;
const bool has_else = (expr.arg_cnt_ % 2 != 0);
int64_t loop = (has_else) ? expr.arg_cnt_ - 1 : expr.arg_cnt_;
bool match_when = false;
ObDatum *when_datum = NULL;
ObDatum *then_datum = NULL;
bool has_result = false;
int64_t expr_idx = 0;
for ( ; OB_SUCC(ret) && !match_when && expr_idx < loop; expr_idx += 2) {
if (OB_FAIL(expr.args_[expr_idx]->eval(ctx, when_datum))) {
LOG_WARN("eval when expr failed", K(ret), K(expr_idx));
} else if (OB_FAIL(check_is_match(*when_datum, match_when))) {
LOG_WARN("check is when expr match failed", K(ret), K(expr_idx));
} else if (match_when) {
if (OB_FAIL(expr.args_[expr_idx+1]->eval(ctx, then_datum))) {
LOG_WARN("eval then expr failed", K(ret), K(expr_idx+1));
} else {
has_result = true;
}
}
}
if (OB_SUCC(ret)) {
if (!match_when) {
if (has_else) {
if (OB_FAIL(expr.args_[expr.arg_cnt_-1]->eval(ctx, then_datum))) {
LOG_WARN("eval else expr failed for case when", K(ret));
} else {
has_result = true;
}
}
}
}
if (OB_SUCC(ret)) {
if (!has_result) {
res_datum.set_null();
} else {
if (OB_ISNULL(then_datum)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("then_datum is NULL", K(ret));
} else {
res_datum.set_datum(*then_datum);
}
}
}
return ret;
}
// Oracle模式下，在deduce type阶段需要将when/then expr类型要一致
int ObExprCase::is_same_kind_type_for_case(const ObIArray<ObExprResType> &type_arr)
{
int ret = OB_SUCCESS;
if (OB_SUCC(ret)) {
bool match = false;
int64_t first_not_null_idx = OB_INVALID_ID;
for (int64_t i = 0; OB_SUCC(ret) &&
OB_INVALID_ID == first_not_null_idx && i < type_arr.count(); ++i) {
if (!ob_is_null(type_arr.at(i).get_type())) {
first_not_null_idx = i;
}
}
first_not_null_idx = OB_INVALID_ID == first_not_null_idx ? 0 : first_not_null_idx;
const ObExprResType &res_type = type_arr.at(first_not_null_idx);
for (int64_t i = first_not_null_idx+1; OB_SUCC(ret) && i < type_arr.count(); ++i) {
if (OB_FAIL(ObExprOperator::is_same_kind_type_for_case(res_type,
type_arr.at(i), match))) {
LOG_WARN("fail to judge same type", K(i), K(res_type), K(type_arr.at(i)), K(ret));
} else if (!match) {
ret = OB_ERR_INVALID_TYPE_FOR_OP;
LOG_WARN("fail to judge same type", K(i), K(res_type), K(type_arr.at(i)), K(ret));
}
}
}
return ret;
}
int ObExprCase::eval_case_batch(const ObExpr &expr,
ObEvalCtx &ctx,
const ObBitVector &skip,
const int64_t batch_size)
{
int ret = OB_SUCCESS;
const bool has_else = (expr.arg_cnt_ % 2 != 0);
int64_t loop = (has_else) ? expr.arg_cnt_ - 1 : expr.arg_cnt_;
bool match_when = false;
ObDatum *results = expr.locate_batch_datums(ctx);
LOG_DEBUG("eval_case_batch", K(expr.arg_cnt_));
if (OB_ISNULL(results)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("results frame is not init", K(ret));
} else {
ObBitVector &eval_flags = expr.get_evaluated_flags(ctx);
ObBitVector *case_when_match = nullptr;
ObBitVector *case_not_match = nullptr;
void * data = nullptr;
void * data1 = nullptr;
ObEvalCtx::TempAllocGuard alloc_guard(ctx);
if (OB_ISNULL(data = alloc_guard.get_allocator().alloc(ObBitVector::memory_size(batch_size)))) {
ret = OB_ALLOCATE_MEMORY_FAILED;
LOG_WARN("failed to alloc memory for case_when_match", K(ret));
} else if (OB_ISNULL(data1 = alloc_guard.get_allocator().alloc(ObBitVector::memory_size(batch_size)))) {
ret = OB_ALLOCATE_MEMORY_FAILED;
LOG_WARN("failed to alloc memory for case_when_match", K(ret));
} else {
case_when_match = to_bit_vector(data);
case_not_match = to_bit_vector(data1);
case_when_match->reset(batch_size);
case_not_match->reset(batch_size);
//case_when_match = eval_flags | skip
case_when_match->bit_calculate(skip, eval_flags, batch_size,
[](const uint64_t l, const uint64_t r) { return (l | r); });
case_not_match->bit_calculate(skip, eval_flags, batch_size,
[](const uint64_t l, const uint64_t r) { return (l | r); });
}
// E.G
// SELECT CASE WHEN expr1 THEN expr2 WHEN expr3 THEN expr4 ... ELSE exprN END
// the logic is
// 1. calc when branch, save result in when_datums and use match_when flag
// to mark which rows are matched in when branch and these rows should be
// calculated in then branch
// 2. calc then branch, put matching result(then_datums) into output datums
// (results)
// REPEAT 1. and 2.
// ...
// LAST.
// calc else branch and put matching result(then_datums) into output datums
for (int64_t expr_idx = 0; OB_SUCC(ret) && expr_idx < loop; expr_idx += 2) {
if (OB_FAIL(expr.args_[expr_idx]->eval_batch(ctx, *case_when_match, batch_size))) {
LOG_WARN("failed to eval batch", K(ret), K(expr_idx));
} else {
ObDatumVector when_datums = expr.args_[expr_idx]->locate_expr_datumvector(ctx);
//first eval when datums
for (int64_t j = 0; OB_SUCC(ret) && j < batch_size; ++j) {
if (case_when_match->at(j)) {
continue;
}
if (OB_FAIL(check_is_match(*when_datums.at(j), match_when))) {
LOG_WARN("check is when expr match failed", K(ret), K(j));
} else if (match_when) {
case_when_match->set(j);
} else {
// not match, mark case_not_match to stop calculating then branch
case_not_match->set(j);
}
}
//now eval then datums
if (OB_FAIL(ret)) {
} else if (OB_FAIL(expr.args_[expr_idx + 1]->eval_batch(ctx, *case_not_match, batch_size))) {
LOG_WARN("failed to eval batch", K(ret), K(expr_idx + 1));
} else {
ObDatumVector then_datums = expr.args_[expr_idx + 1]->locate_expr_datumvector(ctx);
for (int64_t j = 0; OB_SUCC(ret) && j < batch_size; ++j) {
if (case_not_match->at(j)) {
continue;
}
results[j].set_datum(*then_datums.at(j));
eval_flags.set(j);
}
// rows matched in this round should not match in next round, therefor,
// copy last round matched rows flag(case_when_match) into case_not_match
case_not_match->deep_copy(*case_when_match, batch_size);
}
}
}
//now set the result of the rest, skip rows already matched (case_when_match)
if (OB_SUCC(ret)) {
if (has_else) {
if (OB_FAIL(expr.args_[expr.arg_cnt_ - 1]->eval_batch(ctx, *case_when_match, batch_size))) {
LOG_WARN("failed to eval batch", K(ret));
} else {
ObDatumVector else_datums = expr.args_[expr.arg_cnt_ - 1]->locate_expr_datumvector(ctx);
for (int64_t j = 0; OB_SUCC(ret) && j < batch_size; ++j) {
if (case_when_match->at(j)) {
continue;
}
results[j].set_datum(*else_datums.at(j));
eval_flags.set(j);
}
}
} else {
for (int64_t j = 0; OB_SUCC(ret) && j < batch_size; ++j) {
if (case_when_match->at(j)) {
continue;
}
results[j].set_null();
eval_flags.set(j);
}
}
}
}
return ret;
}
}
}