drop-table

src/common/sys/rc.h

@@ -76,7 +76,8 @@ See the Mulan PSL v2 for more details. */
   DEFINE_RC(LOGBUF_FULL)                 \
   DEFINE_RC(LOG_FILE_FULL)               \
   DEFINE_RC(LOG_ENTRY_INVALID)           \
-  DEFINE_RC(UNSUPPORTED)
+  DEFINE_RC(UNSUPPORTED)                 \
+  DEFINE_RC(DELETE_FILE_ERROR)
 
 enum class RC
 {

src/observer/sql/executor/command_executor.cpp

@@ -17,6 +17,7 @@ See the Mulan PSL v2 for more details. */
 #include "event/sql_event.h"
 #include "sql/executor/create_index_executor.h"
 #include "sql/executor/create_table_executor.h"
+#include "sql/executor/drop_table_executor.h"
 #include "sql/executor/desc_table_executor.h"
 #include "sql/executor/help_executor.h"
 #include "sql/executor/load_data_executor.h"
@@ -82,6 +83,11 @@ RC CommandExecutor::execute(SQLStageEvent *sql_event)
       rc = RC::SUCCESS;
     } break;
 
+    case StmtType::DROP_TABLE: {
+      DropTableExecutor executor;
+      rc = executor.execute(sql_event);
+    } break;
+
     default: {
       LOG_ERROR("unknown command: %d", static_cast<int>(stmt->type()));
       rc = RC::UNIMPLEMENTED;

src/observer/sql/executor/drop_table_executor.cpp

@@ -0,0 +1,19 @@
+#include "sql/executor/drop_table_executor.h"
+#include "session/session.h"
+#include "common/log/log.h"
+#include "storage/table/table.h"
+#include "sql/stmt/drop_table_stmt.h"
+#include "event/sql_event.h"
+#include "event/session_event.h"
+#include "storage/db/db.h"
+RC DropTableExecutor::execute(SQLStageEvent *sql_event)
+{
+  Stmt *stmt = sql_event->stmt();
+  Session *session = sql_event->session_event()->session();
+  ASSERT(stmt->type() == StmtType::DROP_TABLE, 
+         "drop table executor can not run this command: %d", static_cast<int>(stmt->type()));
+  DropTableStmt *drop_table_stmt = static_cast<DropTableStmt *>(stmt);
+  const char *table_name = drop_table_stmt->table_name().c_str();
+  RC rc = session->get_current_db()->drop_table(table_name);
+  return rc;
+}

src/observer/sql/executor/drop_table_executor.h

@@ -0,0 +1,14 @@
+#pragma once
+#include "common/sys/rc.h"
+class SQLStageEvent;
+/**
+ * @brief 删除表的执行器
+ * @ingroup Executor
+ */
+class DropTableExecutor
+{
+public:
+  DropTableExecutor() = default;
+  virtual ~DropTableExecutor() = default;
+  RC execute(SQLStageEvent *sql_event);
+};

src/observer/sql/stmt/drop_table_stmt.cpp

@@ -0,0 +1,8 @@
+#include "sql/stmt/drop_table_stmt.h"
+#include "event/sql_debug.h"
+RC DropTableStmt::create(Db *db, const DropTableSqlNode &drop_table, Stmt *&stmt)
+{
+  stmt = new DropTableStmt(drop_table.relation_name);
+  sql_debug("drop table statement: table name %s", drop_table.relation_name.c_str());
+  return RC::SUCCESS;
+}

src/observer/sql/stmt/drop_table_stmt.h

@@ -0,0 +1,23 @@
+#pragma once
+#include <string>
+#include <vector>
+#include "sql/stmt/stmt.h"
+class Db;
+/**
+ * @brief 表示删除表的语句
+ * @ingroup Statement
+ * @details 虽然解析成了stmt，但是与原始的SQL解析后的数据也差不多
+ */
+class DropTableStmt : public Stmt
+{
+public:
+  DropTableStmt(const std::string &table_name)
+        : table_name_(table_name)
+  {}
+  virtual ~DropTableStmt() = default;
+  StmtType type() const override { return StmtType::DROP_TABLE; }
+  const std::string &table_name() const { return table_name_; }
+  static RC create(Db *db, const DropTableSqlNode &create_table, Stmt *&stmt);
+private:
+  std::string table_name_;
+};

src/observer/sql/stmt/stmt.cpp

@@ -17,6 +17,7 @@ See the Mulan PSL v2 for more details. */
 #include "sql/stmt/calc_stmt.h"
 #include "sql/stmt/create_index_stmt.h"
 #include "sql/stmt/create_table_stmt.h"
+#include "sql/stmt/drop_table_stmt.h"
 #include "sql/stmt/delete_stmt.h"
 #include "sql/stmt/desc_table_stmt.h"
 #include "sql/stmt/exit_stmt.h"
@@ -71,6 +72,10 @@ RC Stmt::create_stmt(Db *db, ParsedSqlNode &sql_node, Stmt *&stmt)
       return CreateTableStmt::create(db, sql_node.create_table, stmt);
     }
 
+    case SCF_DROP_TABLE: {
+      return DropTableStmt::create(db, sql_node.drop_table, stmt);
+    }
+
     case SCF_DESC_TABLE: {
       return DescTableStmt::create(db, sql_node.desc_table, stmt);
     }

src/observer/storage/buffer/disk_buffer_pool.cpp

@@ -921,3 +921,21 @@ RC BufferPoolManager::get_buffer_pool(int32_t id, DiskBufferPool *&bp)
   return RC::SUCCESS;
 }
 
+//将相关数据移出bufferpool
+RC BufferPoolManager::remove_file(const char *file_name)
+{
+  RC ret = RC::SUCCESS;
+  if((ret = close_file(file_name)) != RC::SUCCESS)
+  {
+    LOG_WARN("close file fail. file name=%s", file_name);
+  }
+  else
+  {
+    if( 0 != ::remove(file_name))
+    {
+      LOG_WARN("remove file fail. file name=%s, errno = %s", file_name,strerror(errno));
+      ret = RC::FILE_REMOVE;
+    }
+  }
+  return ret;
+}

src/observer/storage/buffer/disk_buffer_pool.h

@@ -332,6 +332,8 @@ class BufferPoolManager final
 
   RC flush_page(Frame &frame);
 
+  RC remove_file(const char *file_name);
+
   BPFrameManager    &get_frame_manager() { return frame_manager_; }
   DoubleWriteBuffer *get_dblwr_buffer() { return dblwr_buffer_.get(); }
 

src/observer/storage/db/db.cpp

@@ -395,6 +395,33 @@ RC Db::init_dblwr_buffer()
   return RC::SUCCESS;
 }
 
+RC Db::drop_table(const char *table_name)
+{
+    RC rc = RC::SUCCESS;
+    Table * table = nullptr;
+    auto it = opened_tables_.find(table_name);
+    if(it == opened_tables_.end())
+    {
+      LOG_WARN("table : %s not exist", table_name);
+      rc = RC::SCHEMA_TABLE_NOT_EXIST;
+    }
+    else if( (table = it->second) == nullptr)
+    {
+      LOG_WARN("table : %s not exist", table_name);
+      rc = RC::SCHEMA_TABLE_NOT_EXIST;
+    }
+    else if((rc = table->drop(path_.c_str())) != RC::SUCCESS)
+    {
+      LOG_WARN("table drop file,errno: %s", strrc(rc));
+    }
+    else
+    {
+      opened_tables_.erase(it);
+      delete table;
+    }
+    return rc;
+}
+
 LogHandler        &Db::log_handler() { return *log_handler_; }
 BufferPoolManager &Db::buffer_pool_manager() { return *buffer_pool_manager_; }
 TrxKit            &Db::trx_kit() { return *trx_kit_; }

src/observer/storage/db/db.h

@@ -87,6 +87,8 @@ class Db
    */
   RC sync();
 
+  RC drop_table(const char *table_name);
+
   /// @brief 获取当前数据库的日志处理器
   LogHandler &log_handler();
 

src/observer/storage/table/table.cpp

@@ -540,3 +540,44 @@ RC Table::sync()
   LOG_INFO("Sync table over. table=%s", name());
   return rc;
 }
+
+RC Table::drop(const char *dir)
+{
+  // 1.drop index first
+  RC rc = RC::SUCCESS;
+  if ((rc = sync()) != RC::SUCCESS) {
+    LOG_WARN("Failed to sync table %s to disk.", name());
+  } else {
+    std::string meta_file = ::table_meta_file(dir, name());
+    // 1.drop  meta file and index file
+    if (0 != ::unlink(meta_file.c_str())) {
+      LOG_WARN("unable to delete %s meta file", name());
+      rc = RC::DELETE_FILE_ERROR;
+    } else {
+      const int index_num = table_meta_.index_num();
+      for (int i = 0; i < index_num; i++) {
+        ((BplusTreeIndex *)indexes_[i])->close();
+        const IndexMeta *index_meta = table_meta_.index(i);
+        if (index_meta != nullptr) {
+          std::string index_file = ::table_index_file(dir, name(), index_meta->name());
+          if (0 != ::unlink(index_file.c_str())) {
+            LOG_WARN("unable to delete %s meta file", name());
+            rc = RC::DELETE_FILE_ERROR;
+            break;
+          }
+        }
+      }
+    }
+  }
+  if (RC::SUCCESS == rc) {
+    // 2.destroy record handler
+    record_handler_->close();
+    delete record_handler_;
+    record_handler_ = nullptr;
+    // 3.destroy buffer pool and remove data file
+    std::string        data_file = table_data_file(dir, name());
+    BufferPoolManager &bpm       = db_->buffer_pool_manager();
+    rc                           = bpm.remove_file(data_file.c_str());
+  }
+  return rc;
+}

src/observer/storage/table/table.h

@@ -110,6 +110,8 @@ class Table
 
   RC sync();
 
+  RC drop(const char *dir);
+
 private:
   RC insert_entry_of_indexes(const char *record, const RID &rid);
   RC delete_entry_of_indexes(const char *record, const RID &rid, bool error_on_not_exists);