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4171483b53
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
105 lines
3.4 KiB
C
105 lines
3.4 KiB
C
/* Copyright (C) 2000 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#include "mysys_priv.h"
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#include "mysys_err.h"
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/*
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Seek to a position in a file.
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ARGUMENTS
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File fd The file descriptor
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my_off_t pos The expected position (absolute or relative)
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int whence A direction parameter and one of
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{SEEK_SET, SEEK_CUR, SEEK_END}
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myf MyFlags MY_THREADSAFE must be set in case my_seek may be mixed
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with my_pread/my_pwrite calls and fd is shared among
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threads.
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DESCRIPTION
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The my_seek function is a wrapper around the system call lseek and
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repositions the offset of the file descriptor fd to the argument
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offset according to the directive whence as follows:
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SEEK_SET The offset is set to offset bytes.
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SEEK_CUR The offset is set to its current location plus offset bytes
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SEEK_END The offset is set to the size of the file plus offset bytes
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RETURN VALUE
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my_off_t newpos The new position in the file.
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MY_FILEPOS_ERROR An error was encountered while performing
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the seek. my_errno is set to indicate the
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actual error.
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*/
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my_off_t my_seek(File fd, my_off_t pos, int whence, myf MyFlags)
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{
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reg1 os_off_t newpos= -1;
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DBUG_ENTER("my_seek");
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DBUG_PRINT("my",("fd: %d Hpos: %lu Pos: %lu Whence: %d MyFlags: %d",
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fd, (ulong) (((ulonglong) pos) >> 32), (ulong) pos,
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whence, MyFlags));
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DBUG_ASSERT(pos != MY_FILEPOS_ERROR); /* safety check */
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/*
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Make sure we are using a valid file descriptor!
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*/
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DBUG_ASSERT(fd != -1);
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#ifdef _WIN32
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newpos= my_win_lseek(fd, pos, whence);
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#else
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newpos= lseek(fd, pos, whence);
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#endif
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if (newpos == (os_off_t) -1)
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{
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my_errno= errno;
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if (MyFlags & MY_WME)
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my_error(EE_CANT_SEEK, MYF(0), my_filename(fd), my_errno);
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DBUG_PRINT("error",("lseek: %lu errno: %d", (ulong) newpos,errno));
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DBUG_RETURN(MY_FILEPOS_ERROR);
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}
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if ((my_off_t) newpos != pos)
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{
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DBUG_PRINT("exit",("pos: %lu", (ulong) newpos));
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}
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DBUG_RETURN((my_off_t) newpos);
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} /* my_seek */
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/* Tell current position of file */
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/* ARGSUSED */
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my_off_t my_tell(File fd, myf MyFlags)
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{
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os_off_t pos;
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DBUG_ENTER("my_tell");
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DBUG_PRINT("my",("fd: %d MyFlags: %d",fd, MyFlags));
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DBUG_ASSERT(fd >= 0);
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#ifdef _WIN32
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pos= my_seek(fd, 0, MY_SEEK_CUR,0);
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#elif defined(HAVE_TELL)
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pos=tell(fd);
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#else
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pos=lseek(fd, 0L, MY_SEEK_CUR);
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#endif
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if (pos == (os_off_t) -1)
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{
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my_errno= errno;
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if (MyFlags & MY_WME)
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my_error(EE_CANT_SEEK, MYF(0), my_filename(fd), my_errno);
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DBUG_PRINT("error", ("tell: %lu errno: %d", (ulong) pos, my_errno));
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}
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DBUG_PRINT("exit",("pos: %lu", (ulong) pos));
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DBUG_RETURN((my_off_t) pos);
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} /* my_tell */
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