Files
oceanbase/src/sql/engine/basic/ob_count_op.cpp
oceanbase-admin cea7de1475 init push
2021-05-31 22:56:52 +08:00

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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 "ob_count_op.h"
#include "sql/engine/ob_physical_plan.h"
#include "sql/engine/ob_exec_context.h"
namespace oceanbase {
namespace sql {
ObCountSpec::ObCountSpec(ObIAllocator& alloc, const ObPhyOperatorType type)
: ObOpSpec(alloc, type), rownum_limit_(NULL), anti_monotone_filters_(alloc)
{}
OB_SERIALIZE_MEMBER((ObCountSpec, ObOpSpec), rownum_limit_, anti_monotone_filters_);
ObCountOp::ObCountOp(ObExecContext& exec_ctx, const ObOpSpec& spec, ObOpInput* input)
: ObOperator(exec_ctx, spec, input)
{
reset_default();
}
void ObCountOp::reset_default()
{
cur_rownum_ = 0;
rownum_limit_ = INT64_MAX;
}
int ObCountOp::inner_open()
{
int ret = OB_SUCCESS;
if (OB_ISNULL(child_)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("count operator has no child", K(ret));
} else if (OB_FAIL(get_rownum_limit())) {
LOG_WARN("get rownum limit failed", K(ret));
}
return ret;
}
int ObCountOp::get_rownum_limit()
{
int ret = OB_SUCCESS;
ObExpr* expr = MY_SPEC.rownum_limit_;
if (NULL != expr) {
ObDatum* datum = NULL;
if (OB_FAIL(expr->eval(eval_ctx_, datum))) {
LOG_WARN("limit expr evaluate failed", K(ret));
} else {
if (datum->null_) {
rownum_limit_ = 0;
} else {
OB_ASSERT(ob_is_int_tc(expr->datum_meta_.type_));
rownum_limit_ = *datum->int_;
}
}
}
return ret;
}
int ObCountOp::rescan()
{
int ret = OB_SUCCESS;
if (OB_FAIL(ObOperator::rescan())) {
if (OB_ITER_END != ret) {
LOG_WARN("operator rescan fail", K(ret));
}
} else {
reset_default();
OZ(get_rownum_limit());
}
return ret;
}
int ObCountOp::switch_iterator()
{
int ret = OB_SUCCESS;
if (OB_FAIL(ObOperator::switch_iterator())) {
if (OB_ITER_END != ret) {
LOG_WARN("operator switch iterator fail", K(ret));
}
} else {
reset_default();
OZ(get_rownum_limit());
}
return ret;
}
int ObCountOp::get_next_row()
{
int ret = OB_SUCCESS;
if (cur_rownum_ >= rownum_limit_) {
ret = OB_ITER_END;
} else {
cur_rownum_ += 1;
if (OB_FAIL(ObOperator::get_next_row())) {
cur_rownum_ -= 1;
if (OB_ITER_END != ret) {
LOG_WARN("operator get next row failed", K(ret));
}
}
}
return ret;
}
int ObCountOp::inner_get_next_row()
{
int ret = OB_SUCCESS;
if (OB_FAIL(child_->get_next_row())) {
if (OB_ITER_END != ret) {
LOG_WARN("get row from child failed", K(ret));
}
} else {
clear_evaluated_flag();
if (!MY_SPEC.anti_monotone_filters_.empty()) {
bool filtered = false;
if (OB_FAIL(filter(MY_SPEC.anti_monotone_filters_, filtered))) {
LOG_WARN("filter row failed", K(ret));
} else if (filtered) {
// Set rownum limit to zero make it return OB_ITER_END directly on next call.
rownum_limit_ = 0;
ret = OB_ITER_END;
}
}
}
return ret;
}
} // end namespace sql
} // end namespace oceanbase