mariadb/mysys/my_file.c
Vladislav Vaintroub 4171483b53 Backport Fix for Bug#24509 - 2048 file descriptor limit on windows needs increasing.
The patch replaces the use of the POSIX I/O interfaces in mysys on Windows with 
the Win32 API calls (CreateFile, WriteFile, etc). The Windows HANDLE for the open
 file is stored in the my_file_info struct, along with a flag for append mode 
(because the Windows API does not support opening files in append mode in all cases)
The default max open files has been increased to 16384 and can be increased further
by setting --max-open-files=<value> during the server start.

Noteworthy benefit of this patch is that it removes limits from the table_cache size - 
allowing for more simultaneus users
2011-06-12 15:52:07 +02:00

135 lines
3.8 KiB
C

/* Copyright (C) 2000 MySQL AB
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include "mysys_priv.h"
#include "my_static.h"
#include <m_string.h>
/*
set how many open files we want to be able to handle
SYNOPSIS
set_maximum_open_files()
max_file_limit Files to open
NOTES
The request may not fulfilled becasue of system limitations
RETURN
Files available to open.
May be more or less than max_file_limit!
*/
#if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
#ifndef RLIM_INFINITY
#define RLIM_INFINITY ((uint) 0xffffffff)
#endif
static uint set_max_open_files(uint max_file_limit)
{
struct rlimit rlimit;
uint old_cur;
DBUG_ENTER("set_max_open_files");
DBUG_PRINT("enter",("files: %u", max_file_limit));
if (!getrlimit(RLIMIT_NOFILE,&rlimit))
{
old_cur= (uint) rlimit.rlim_cur;
DBUG_PRINT("info", ("rlim_cur: %u rlim_max: %u",
(uint) rlimit.rlim_cur,
(uint) rlimit.rlim_max));
if ((ulonglong) rlimit.rlim_cur == (ulonglong) RLIM_INFINITY)
rlimit.rlim_cur = max_file_limit;
if (rlimit.rlim_cur >= max_file_limit)
DBUG_RETURN(rlimit.rlim_cur); /* purecov: inspected */
rlimit.rlim_cur= rlimit.rlim_max= max_file_limit;
if (setrlimit(RLIMIT_NOFILE, &rlimit))
max_file_limit= old_cur; /* Use original value */
else
{
rlimit.rlim_cur= 0; /* Safety if next call fails */
(void) getrlimit(RLIMIT_NOFILE,&rlimit);
DBUG_PRINT("info", ("rlim_cur: %u", (uint) rlimit.rlim_cur));
if (rlimit.rlim_cur) /* If call didn't fail */
max_file_limit= (uint) rlimit.rlim_cur;
}
}
DBUG_PRINT("exit",("max_file_limit: %u", max_file_limit));
DBUG_RETURN(max_file_limit);
}
#else
static uint set_max_open_files(uint max_file_limit)
{
/* We don't know the limit. Return best guess */
return min(max_file_limit, OS_FILE_LIMIT);
}
#endif
/*
Change number of open files
SYNOPSIS:
my_set_max_open_files()
files Number of requested files
RETURN
number of files available for open
*/
uint my_set_max_open_files(uint files)
{
struct st_my_file_info *tmp;
DBUG_ENTER("my_set_max_open_files");
DBUG_PRINT("enter",("files: %u my_file_limit: %u", files, my_file_limit));
files+= MY_FILE_MIN;
files= set_max_open_files(min(files, OS_FILE_LIMIT));
if (files <= MY_NFILE)
DBUG_RETURN(files);
if (!(tmp= (struct st_my_file_info*) my_malloc(sizeof(*tmp) * files,
MYF(MY_WME))))
DBUG_RETURN(MY_NFILE);
/* Copy any initialized files */
memcpy((char*) tmp, (char*) my_file_info,
sizeof(*tmp) * min(my_file_limit, files));
bzero((char*) (tmp + my_file_limit),
max((int) (files- my_file_limit), 0)*sizeof(*tmp));
my_free_open_file_info(); /* Free if already allocated */
my_file_info= tmp;
my_file_limit= files;
DBUG_PRINT("exit",("files: %u", files));
DBUG_RETURN(files);
}
void my_free_open_file_info()
{
DBUG_ENTER("my_free_file_info");
if (my_file_info != my_file_info_default)
{
/* Copy data back for my_print_open_files */
memcpy((char*) my_file_info_default, my_file_info,
sizeof(*my_file_info_default)* MY_NFILE);
my_free((char*) my_file_info, MYF(0));
my_file_info= my_file_info_default;
my_file_limit= MY_NFILE;
}
DBUG_VOID_RETURN;
}