mariadb/storage/perfschema/table_file_instances.cc

/* Copyright (c) 2008, 2023, 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 Free Software Foundation.

  This program is also distributed with certain software (including
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  as designated in a particular file or component or in included license
  documentation.  The authors of MySQL hereby grant you an additional
  permission to link the program and your derivative works with the
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  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, version 2.0, 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,
  51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */

/**
  @file storage/perfschema/table_file_instances.cc
  Table FILE_INSTANCES (implementation).
*/

#include "my_global.h"
#include "my_thread.h"
#include "pfs_instr.h"
#include "pfs_column_types.h"
#include "pfs_column_values.h"
#include "table_file_instances.h"
#include "pfs_global.h"
#include "pfs_buffer_container.h"
#include "field.h"

THR_LOCK table_file_instances::m_table_lock;
PFS_engine_table_share_state
table_file_instances::m_share_state = {
  false /* m_checked */
};

PFS_engine_table_share
table_file_instances::m_share=
{
  { C_STRING_WITH_LEN("file_instances") },
  &pfs_readonly_acl,
  table_file_instances::create,
  NULL, /* write_row */
  NULL, /* delete_all_rows */
  table_file_instances::get_row_count,
  sizeof(PFS_simple_index),
  &m_table_lock,
  { C_STRING_WITH_LEN("CREATE TABLE file_instances("
                      "FILE_NAME VARCHAR(512) not null comment 'File name.',"
                      "EVENT_NAME VARCHAR(128) not null comment 'Instrument name associated with the file.',"
                      "OPEN_COUNT INTEGER unsigned not null comment 'Open handles on the file. A value of greater than zero means that the file is currently open.')") },
  false, /* m_perpetual */
  false, /* m_optional */
  &m_share_state
};

PFS_engine_table* table_file_instances::create(void)
{
  return new table_file_instances();
}

ha_rows
table_file_instances::get_row_count(void)
{
  return global_file_container.get_row_count();
}

table_file_instances::table_file_instances()
  : PFS_engine_table(&m_share, &m_pos),
  m_row_exists(false), m_pos(0), m_next_pos(0)
{}

void table_file_instances::reset_position(void)
{
  m_pos.m_index= 0;
  m_next_pos.m_index= 0;
}

int table_file_instances::rnd_next(void)
{
  PFS_file *pfs;

  m_pos.set_at(&m_next_pos);
  PFS_file_iterator it= global_file_container.iterate(m_pos.m_index);
  pfs= it.scan_next(& m_pos.m_index);
  if (pfs != NULL)
  {
    make_row(pfs);
    m_next_pos.set_after(&m_pos);
    return 0;
  }

  return HA_ERR_END_OF_FILE;
}

int table_file_instances::rnd_pos(const void *pos)
{
  PFS_file *pfs;

  set_position(pos);

  pfs= global_file_container.get(m_pos.m_index);
  if (pfs != NULL)
  {
    make_row(pfs);
    return 0;
  }

  return HA_ERR_RECORD_DELETED;
}

void table_file_instances::make_row(PFS_file *pfs)
{
  pfs_optimistic_state lock;
  PFS_file_class *safe_class;

  m_row_exists= false;

  /* Protect this reader against a file delete */
  pfs->m_lock.begin_optimistic_lock(&lock);

  safe_class= sanitize_file_class(pfs->m_class);
  if (unlikely(safe_class == NULL))
    return;

  m_row.m_filename= pfs->m_filename;
  m_row.m_filename_length= pfs->m_filename_length;
  m_row.m_event_name= safe_class->m_name;
  m_row.m_event_name_length= safe_class->m_name_length;
  m_row.m_open_count= pfs->m_file_stat.m_open_count;

  if (pfs->m_lock.end_optimistic_lock(&lock))
    m_row_exists= true;
}

int table_file_instances::read_row_values(TABLE *table,
                                          unsigned char *,
                                          Field **fields,
                                          bool read_all)
{
  Field *f;

  if (unlikely(! m_row_exists))
    return HA_ERR_RECORD_DELETED;

  /* Set the null bits */
  assert(table->s->null_bytes == 0);

  for (; (f= *fields) ; fields++)
  {
    if (read_all || bitmap_is_set(table->read_set, f->field_index))
    {
      switch(f->field_index)
      {
      case 0: /* FILENAME */
        set_field_varchar_utf8(f, m_row.m_filename, m_row.m_filename_length);
        break;
      case 1: /* EVENT_NAME */
        set_field_varchar_utf8(f, m_row.m_event_name,
                               m_row.m_event_name_length);
        break;
      case 2: /* OPEN_COUNT */
        set_field_ulong(f, m_row.m_open_count);
        break;
      default:
        assert(false);
      }
    }
  }

  return 0;
}