oceanbase/src/sql/plan_cache/ob_ps_cache_callback.cpp

/**
 * 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_PC
#include "ob_ps_cache_callback.h"


namespace oceanbase
{
using namespace common;
namespace sql
{

void ObPsStmtItemRefAtomicOp::operator()(const PsStmtIdKV &entry)
{
  if (NULL != entry.second) {
    if (entry.second->check_erase_inc_ref_count()) {//已经被其他线程标记位
      callback_ret_ = OB_EAGAIN;
      LOG_INFO("element will be free, try again", K(entry), K(callback_ret_));
    } else {//执行到该代码块时引用计数不会为0，因为operator()会受hashtable中的lock保护
      callback_ret_ = OB_SUCCESS;
      stmt_item_ = entry.second;
    }
  } else {
    callback_ret_ = OB_ERR_UNEXPECTED;
    LOG_WARN_RET(callback_ret_, "value is NULL", K(entry), K(callback_ret_));
  }
}

int ObPsStmtItemRefAtomicOp::get_value(ObPsStmtItem *&ps_item)
{
  int ret = OB_SUCCESS;
  ps_item = NULL;
  if (OB_ISNULL(stmt_item_)) {
    ret = OB_NOT_INIT;
    LOG_WARN("stmt_item should not be null", K(ret));
  } else {
    ps_item = stmt_item_;
  }
  return ret;
}

void ObPsStmtItemDerefAtomicOp::operator()(const PsStmtIdKV &entry)
{
  if (OB_ISNULL(entry.second)) {
    ret_ = OB_HASH_NOT_EXIST;
    LOG_WARN_RET(ret_, "entry not exist", K_(ret));
  } else {
    entry.second->dec_ref_count_check_erase();
  }
}

void ObPsStmtItemEraseAtomicOp::operator()(const PsStmtIdKV &entry)
{
  if (OB_ISNULL(entry.second)) {
    ret_ = OB_HASH_NOT_EXIST;
    LOG_WARN_RET(ret_, "entry not exist", K_(ret));
  } else if (entry.second->get_ps_stmt_id() == stmt_id_) {
    if (ATOMIC_BCAS(entry.second->get_is_expired_evicted_ptr(), false, true)) {
      need_erase_ = true;
    }
  }
}

void ObPsStmtInfoRefAtomicOp::operator ()(const PsStmtInfoKV &entry)
{
  if (NULL != entry.second) {
    if (entry.second->check_erase_inc_ref_count()) {//已经被其他线程标记位
      callback_ret_ = OB_EAGAIN;
      LOG_INFO("element will be free, try again", K(entry), K(callback_ret_));
    } else {//执行到该代码块时引用计数不会为0，因为operator()会受hashtable中的lock保护
      callback_ret_ = OB_SUCCESS;
      stmt_info_ = entry.second;
    }
  } else {
    callback_ret_ = OB_ERR_UNEXPECTED;
    LOG_WARN_RET(callback_ret_, "value is NULL", K(entry), K(callback_ret_));
  }
}

int ObPsStmtInfoRefAtomicOp::get_value(ObPsStmtInfo *&ps_info)
{
  int ret = OB_SUCCESS;
  ps_info = NULL;
  if (OB_ISNULL(stmt_info_)) {
    ret = OB_NOT_INIT;
    LOG_WARN("stmt info should not be null", K(ret));
  } else {
    ps_info = stmt_info_;
  }
  return ret;
}

void ObPsStmtInfoDerefAtomicOp::operator()(const PsStmtInfoKV &entry)
{
  if (OB_ISNULL(entry.second)) {
    ret_ = OB_HASH_NOT_EXIST;
    LOG_WARN_RET(ret_, "entry not exist", K_(ret));
  } else {
    is_erase_ = entry.second->dec_ref_count_check_erase();
    if (is_erase_) {
      LOG_INFO("erase stmt info", "stmt_info", *entry.second, "stmt_id", entry.first);
    }
  }
}

void ObPsPCVSetAtomicOp::operator()(PsPlanCacheKV &entry)
{
  if (NULL != entry.second) {
    entry.second->inc_ref_count(ref_handle_);
    pcv_set_ = entry.second;
    SQL_PC_LOG(DEBUG, "succ to get plan cache value", "ref_count", pcv_set_->get_ref_count());
  } else {
    // if no pcv set found, no need to do anything now
  }
}

//get pcvs and lock
int ObPsPCVSetAtomicOp::get_value(ObPCVSet *&pcvs)
{
  int ret = OB_SUCCESS;
  pcvs = NULL;
  if (OB_ISNULL(pcv_set_)) {
    ret = OB_NOT_INIT;
    SQL_PC_LOG(WARN, "invalid argument", K(pcv_set_));
  } else if (OB_SUCC(lock(*pcv_set_))) {
    pcvs = pcv_set_;
  } else {
    if (NULL != pcv_set_) {
      pcv_set_->dec_ref_count(ref_handle_);
    }
    SQL_PC_LOG(ERROR, "failed to get read lock of plan cache value", K(ret));
  }
  return ret;
}
}
}