5.7.13

storage/perfschema/table_variables_by_thread.h

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+/* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; version 2 of the License.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
+
+#ifndef TABLE_VARIABLES_BY_THREAD_H
+#define TABLE_VARIABLES_BY_THREAD_H
+
+/**
+  @file storage/perfschema/table_variables_by_thread.h
+  Table VARIABLES_BY_THREAD (declarations).
+*/
+
+#include "pfs_column_types.h"
+#include "pfs_engine_table.h"
+#include "pfs_instr_class.h"
+#include "pfs_instr.h"
+#include "table_helper.h"
+#include "pfs_variable.h"
+#include "pfs_buffer_container.h"
+
+/**
+  @addtogroup Performance_schema_tables
+  @{
+*/
+
+/**
+  A row of table
+  PERFORMANCE_SCHEMA.VARIABLES_BY_THREAD.
+*/
+struct row_variables_by_thread
+{
+  /** Column THREAD_ID. */
+  ulonglong m_thread_internal_id;
+  /** Column VARIABLE_NAME. */
+  PFS_variable_name_row m_variable_name;
+  /** Column VARIABLE_VALUE. */
+  PFS_variable_value_row m_variable_value;
+};
+
+/**
+  Position of a cursor on
+  PERFORMANCE_SCHEMA.VARIABLES_BY_THREAD.
+  Index 1 on thread (0 based)
+  Index 2 on system variable (0 based)
+*/
+struct pos_variables_by_thread
+: public PFS_double_index
+{
+  pos_variables_by_thread()
+    : PFS_double_index(0, 0)
+  {}
+
+  inline void reset(void)
+  {
+    m_index_1= 0;
+    m_index_2= 0;
+  }
+
+  inline bool has_more_thread(void)
+  { return (m_index_1 < global_thread_container.get_row_count()); }
+
+  inline void next_thread(void)
+  {
+    m_index_1++;
+    m_index_2= 0;
+  }
+};
+
+/**
+  Store and retrieve table state information during queries that reinstantiate
+  the table object.
+*/
+class table_variables_by_thread_context : public PFS_table_context
+{
+public:
+  table_variables_by_thread_context(ulonglong hash_version, bool restore) :
+    PFS_table_context(hash_version, global_thread_container.get_row_count(), restore, THR_PFS_VBT) { }
+};
+
+/** Table PERFORMANCE_SCHEMA.VARIABLES_BY_THREAD. */
+class table_variables_by_thread : public PFS_engine_table
+{
+  typedef pos_variables_by_thread pos_t;
+
+public:
+  /** Table share */
+  static PFS_engine_table_share m_share;
+  static PFS_engine_table* create();
+  static ha_rows get_row_count();
+
+  virtual int rnd_init(bool scan);
+  virtual int rnd_next();
+  virtual int rnd_pos(const void *pos);
+  virtual void reset_position(void);
+
+protected:
+  virtual int read_row_values(TABLE *table,
+                              unsigned char *buf,
+                              Field **fields,
+                              bool read_all);
+  table_variables_by_thread();
+
+public:
+  ~table_variables_by_thread()
+  {}
+
+protected:
+  int materialize(PFS_thread *thread);
+  void make_row(PFS_thread *thread, const System_variable *system_var);
+
+private:
+  /** Table share lock. */
+  static THR_LOCK m_table_lock;
+  /** Fields definition. */
+  static TABLE_FIELD_DEF m_field_def;
+
+  /** Current THD variables. */
+  PFS_system_variable_cache m_sysvar_cache;
+  /** Current row. */
+  row_variables_by_thread m_row;
+  /** True if the current row exists. */
+  bool m_row_exists;
+  /** Current position. */
+  pos_t m_pos;
+  /** Next position. */
+  pos_t m_next_pos;
+
+  /** Table context with system variable hash version and map of materialized threads. */
+  table_variables_by_thread_context *m_context;
+};
+
+/** @} */
+#endif