table.h

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/* Copyright (c) 2016, 2025, Oracle and/or its affiliates.
 
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License, version 2.0, as published by the
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as designated in a particular file or component or in included license
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/** @file storage/temptable/include/temptable/table.h
TempTable Table declarations. */
 
#ifndef TEMPTABLE_TABLE_H
#define TEMPTABLE_TABLE_H
 
#include <cstddef>
#include <functional>
#include <string>
#include <utility>
#include <vector>
 
#include "sql/table.h"
#include "storage/temptable/include/temptable/allocator.h"
#include "storage/temptable/include/temptable/column.h"
#include "storage/temptable/include/temptable/cursor.h"
#include "storage/temptable/include/temptable/index.h"
#include "storage/temptable/include/temptable/result.h"
#include "storage/temptable/include/temptable/row.h"
#include "storage/temptable/include/temptable/storage.h"
 
namespace temptable {
 
class Table {
 public:
  Table(TABLE *mysql_table, Block *shared_block,
        bool all_columns_are_fixed_size, size_t tmp_table_size_limit);
 
  /* The `m_rows` member is too expensive to copy around. */
  Table(const Table &) = delete;
  Table &operator=(const Table &) = delete;
 
  Table(Table &&other) = delete;
  Table &operator=(Table &&rhs) = delete;
 
  ~Table();
 
  const TABLE_SHARE *mysql_table_share() const;
 
  size_t mysql_row_length() const;
 
  size_t number_of_indexes() const;
 
  size_t number_of_columns() const;
 
  const Columns &columns() const;
 
  size_t number_of_rows() const;
 
  const Index &index(size_t i) const;
 
  const Column &column(size_t i) const;
 
  const Storage &rows() const;
 
  void row(const Storage::Iterator &pos, unsigned char *mysql_row) const;
 
  /** Insert a new row in the table. If something else than Result::OK is
   * returned, then the state of the table and its indexes is unchanged by the
   * call of this method (ie the method takes care to clean up any half
   * completed work in case of an error and restore the table to its state
   * before this method was called).
   * @return result code */
  Result insert(
      /** [in] The contents of the new row to be inserted. */
      const unsigned char *mysql_row);
 
  /** Update a row in the table. The semantics of this are enforced by the
   * handler API. If something else than Result::OK is returned, then the state
   * of the table and its indexes is unchanged by the call of this method (ie
   * the method takes care to clean up any half completed work in case of an
   * error and restore the table to its state before this method was called).
   * @return result code */
  Result update(
      /** [in] The contents of the old row to be updated. The row pointed to by
       * `target_row` must equal this. */
      const unsigned char *mysql_row_old,
      /** [in] The contents of the new row. */
      const unsigned char *mysql_row_new,
      /** [in,out] Position in the list of rows to update. The row pointed to
       * by this must equal `mysql_row_old`. */
      Storage::Element *target_row);
 
  Result remove(const unsigned char *mysql_row_must_be,
                const Storage::Iterator &victim_position);
 
  void truncate();
 
  Result disable_indexes();
 
  Result enable_indexes();
 
  /** Returns the ID of the owner THD.
   * @retval ID of the THD of the session using this temptable */
  my_thread_id owner_id() const;
 
 private:
  /** Index entry for storing index pointer as well
   * as allocated memory size. */
  struct Index_entry {
    Index *m_index;
 
    size_t m_alloc_size;
  };
 
  /** Check if the table is indexed.
   *
   * @retval true if there are any indexes defined and not disabled.
   * @retval false table is not indexed.
   */
  bool indexed() const;
 
  /** Create index for given key and append it to indexes table. */
  template <class T>
  void append_new_index(const KEY &mysql_index);
 
  /** Create the indexes in `m_index_entries`
   * from `m_mysql_table->key_info[]`. */
  void indexes_create();
 
  /** Destroy the indexes in `m_index_entries`. */
  void indexes_destroy();
 
  bool is_index_update_needed(const unsigned char *mysql_row_old,
                              const unsigned char *mysql_row_new) const;
 
  Result indexes_insert(Storage::Element *row);
 
  Result indexes_remove(Storage::Element *row);
 
  TableResourceMonitor m_resource_monitor;
 
  /** Allocator for all members that need dynamic memory allocation. */
  Allocator<uint8_t> m_allocator;
 
  /** Rows of the table. */
  Storage m_rows;
 
  bool m_all_columns_are_fixed_size;
 
  bool m_indexes_are_enabled;
 
  uint32_t m_mysql_row_length;
 
  std::vector<Index_entry, Allocator<Index_entry>> m_index_entries;
 
  std::vector<Cursor, Allocator<Cursor>> m_insert_undo;
 
  Columns m_columns;
 
  TABLE_SHARE *m_mysql_table_share;
 
  my_thread_id m_owner_id{};
};
 
/* Implementation of inlined methods. */
 
inline const TABLE_SHARE *Table::mysql_table_share() const {
  return m_mysql_table_share;
}
 
inline size_t Table::mysql_row_length() const { return m_mysql_row_length; }
 
inline size_t Table::number_of_indexes() const {
  return m_index_entries.size();
}
 
inline size_t Table::number_of_columns() const { return m_columns.size(); }
 
inline const Columns &Table::columns() const { return m_columns; }
 
inline size_t Table::number_of_rows() const { return m_rows.size(); }
 
inline const Index &Table::index(size_t i) const {
  return *m_index_entries[i].m_index;
}
 
inline const Column &Table::column(size_t i) const {
  assert(i < m_columns.size());
  return m_columns[i];
}
 
inline const Storage &Table::rows() const { return m_rows; }
 
inline void Table::row(const Storage::Iterator &pos,
                       unsigned char *mysql_row) const {
  assert(m_mysql_row_length == m_mysql_table_share->rec_buff_length);
 
  const Storage::Element *storage_element = *pos;
 
  if (m_all_columns_are_fixed_size) {
    assert(m_rows.element_size() == m_mysql_row_length);
 
    memcpy(mysql_row, storage_element, m_mysql_row_length);
  } else {
    assert(m_rows.element_size() == sizeof(Row));
 
    const Row *row = static_cast<const Row *>(storage_element);
    row->copy_to_mysql_row(m_columns, mysql_row, m_mysql_row_length);
  }
}
 
inline void Table::truncate() {
  if (!m_all_columns_are_fixed_size) {
    for (auto element : m_rows) {
      Row *row = static_cast<Row *>(element);
      row->~Row();
    }
  }
  m_rows.clear();
 
  /* Truncate indexes even if `m_indexes_are_enabled` is false. Somebody may
   * use truncate() before enabling indexes and we don't want an empty m_rows
   * with some stale data inside the indexes. */
  for (auto &entry : m_index_entries) {
    entry.m_index->truncate();
  }
}
 
inline Result Table::disable_indexes() {
  m_indexes_are_enabled = false;
  return Result::OK;
}
 
inline Result Table::enable_indexes() {
  if (m_rows.size() == 0 || m_indexes_are_enabled) {
    m_indexes_are_enabled = true;
    return Result::OK;
  }
 
  return Result::WRONG_COMMAND;
}
 
inline bool Table::indexed() const {
  return m_indexes_are_enabled && !m_index_entries.empty();
}
 
/** Create index for given key and appends it to indexes table. */
template <class T>
inline void Table::append_new_index(const KEY &mysql_index) {
  Index_entry entry;
 
  entry.m_alloc_size = sizeof(T);
 
  auto mem_ptr = m_allocator.allocate(entry.m_alloc_size);
  try {
    entry.m_index = new (mem_ptr) T(*this, mysql_index, m_allocator);
 
    m_index_entries.push_back(entry);
  } catch (...) {
    m_allocator.deallocate(mem_ptr, entry.m_alloc_size);
    throw;
  }
}
 
} /* namespace temptable */
 
#endif /* TEMPTABLE_TABLE_H */