diff options
Diffstat (limited to 'mysys/raid.cc')
| -rw-r--r-- | mysys/raid.cc | 162 |
1 files changed, 80 insertions, 82 deletions
diff --git a/mysys/raid.cc b/mysys/raid.cc index 47326f29f60..d6359dc0f93 100644 --- a/mysys/raid.cc +++ b/mysys/raid.cc @@ -1,82 +1,81 @@ -/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB - - This library is free software; you can redistribute it and/or - modify it under the terms of the GNU Library General Public - License as published by the Free Software Foundation; either - version 2 of the License, or (at your option) any later version. - - This library is distributed in the hope that it will be useful, +/* 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; either version 2 of the License, or + (at your option) any later version. + + 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 - Library General Public License for more details. - - You should have received a copy of the GNU Library General Public - License along with this library; if not, write to the Free - Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, - MA 02111-1307, USA */ - -/* --------------------------------------------------------* -* -* RAID support for MySQL. Raid 0 (stiping) only implemented yet. -* -* Why RAID? Why it must be in MySQL? -* -* This is because then you can: -* 1. Have bigger tables than your OS limit. In time of writing this -* we are hitting to 2GB limit under linux/ext2 -* 2. You can get more speed from IO bottleneck by putting -* Raid dirs on different physical disks. -* 3. Getting more fault tolerance (not implemented yet) -* -* Why not to use RAID: -* -* 1. You are losing some processor power to calculate things, -* do more syscalls and interrupts. -* -* Functionality is supplied by two classes: RaidFd and RaidName. -* RaidFd supports funtionality over file descriptors like -* open/create/write/seek/close. RaidName supports functionality -* like rename/delete where we have no relations to filedescriptors. -* RaidName can be prorably unchanged for different Raid levels. RaidFd -* have to be virtual I think ;). -* You can speed up some calls in MySQL code by skipping RAID code. -* For example LOAD DATA INFILE never needs to read RAID-ed files. -* This can be done adding proper "#undef my_read" or similar undef-s -* in your code. Check out the raid.h! -* -* Some explanation about _seek_vector[] -* This is seek cache. RAID seeks too much and we cacheing this. We -* fool it and just storing new position in file to _seek_vector. -* When there is no seeks to do, we are putting RAID_SEEK_DONE into it. -* Any other value requires seeking to that position. -* -* TODO: -* -* -* - Implement other fancy things like RAID 1 (mirroring) and RAID 5. -* Should not to be very complex. -* -* - Optimize big blob writes by resorting write buffers and writing -* big chunks at once instead of doing many syscalls. - after thinking I -* found this is useless. This is because same thing one can do with just -* increasing RAID_CHUNKSIZE. Monty, what do you think? tonu. -* -* - If needed, then implement missing syscalls. One known to miss is stat(); -* -* - Make and use a thread safe dynamic_array buffer. The used one -* will not work if needs to be extended at the same time someone is -* accessing it. -* -* -* tonu@mysql.com & monty@mysql.com -* --------------------------------------------------------*/ + 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 */ + +/* + + RAID support for MySQL. Raid 0 (stiping) only implemented yet. + + Why RAID? Why it must be in MySQL? + + This is because then you can: + 1. Have bigger tables than your OS limit. In time of writing this + we are hitting to 2GB limit under linux/ext2 + 2. You can get more speed from IO bottleneck by putting + Raid dirs on different physical disks. + 3. Getting more fault tolerance (not implemented yet) + + Why not to use RAID: + + 1. You are losing some processor power to calculate things, + do more syscalls and interrupts. + + Functionality is supplied by two classes: RaidFd and RaidName. + RaidFd supports funtionality over file descriptors like + open/create/write/seek/close. RaidName supports functionality + like rename/delete where we have no relations to filedescriptors. + RaidName can be prorably unchanged for different Raid levels. RaidFd + have to be virtual I think ;). + You can speed up some calls in MySQL code by skipping RAID code. + For example LOAD DATA INFILE never needs to read RAID-ed files. + This can be done adding proper "#undef my_read" or similar undef-s + in your code. Check out the raid.h! + + Some explanation about _seek_vector[] + This is seek cache. RAID seeks too much and we cacheing this. We + fool it and just storing new position in file to _seek_vector. + When there is no seeks to do, we are putting RAID_SEEK_DONE into it. + Any other value requires seeking to that position. + + TODO: + + + - Implement other fancy things like RAID 1 (mirroring) and RAID 5. + Should not to be very complex. + + - Optimize big blob writes by resorting write buffers and writing + big chunks at once instead of doing many syscalls. - after thinking I + found this is useless. This is because same thing one can do with just + increasing RAID_CHUNKSIZE. Monty, what do you think? tonu. + + - If needed, then implement missing syscalls. One known to miss is stat(); + + - Make and use a thread safe dynamic_array buffer. The used one + will not work if needs to be extended at the same time someone is + accessing it. + + + tonu@mysql.com & monty@mysql.com +*/ #ifdef __GNUC__ #pragma implementation // gcc: Class implementation #endif #include "mysys_priv.h" -#include "my_dir.h" +#include <my_dir.h> #include <m_string.h> #include <assert.h> @@ -282,7 +281,7 @@ extern "C" { DBUG_RETURN(my_close(fd, MyFlags)); } - int my_raid_chsize(File fd, my_off_t newlength, myf MyFlags) + int my_raid_chsize(File fd, my_off_t newlength, int filler, myf MyFlags) { DBUG_ENTER("my_raid_chsize"); DBUG_PRINT("enter",("Fd: %d newlength: %u MyFlags: %d", @@ -290,10 +289,10 @@ extern "C" { if (is_raid(fd)) { RaidFd *raid= (*dynamic_element(&RaidFd::_raid_map,fd,RaidFd**)); - DBUG_RETURN(raid->Chsize(fd, newlength, MyFlags)); + DBUG_RETURN(raid->Chsize(fd, newlength, filler, MyFlags)); } else - DBUG_RETURN(my_chsize(fd, newlength, MyFlags)); + DBUG_RETURN(my_chsize(fd, newlength, filler, MyFlags)); } int my_raid_rename(const char *from, const char *to, @@ -410,8 +409,8 @@ IsRaid(File fd) RaidFd:: RaidFd(uint raid_type, uint raid_chunks, ulong raid_chunksize) :_raid_type(raid_type), _raid_chunks(raid_chunks), - _raid_chunksize(raid_chunksize), _position(0), _fd_vector(0), - _size(RAID_SIZE_UNKNOWN) + _raid_chunksize(raid_chunksize), _position(0), _size(RAID_SIZE_UNKNOWN), + _fd_vector(0) { DBUG_ENTER("RaidFd::RaidFd"); DBUG_PRINT("enter",("RaidFd_type: %u Disks: %u Chunksize: %d", @@ -739,7 +738,7 @@ Tell(myf MyFlags) } int RaidFd:: -Chsize(File fd, my_off_t newlength, myf MyFlags) +Chsize(File fd, my_off_t newlength, int filler, myf MyFlags) { DBUG_ENTER("RaidFd::Chsize"); DBUG_PRINT("enter",("Fd: %d, newlength: %d, MyFlags: %d", @@ -753,17 +752,16 @@ Chsize(File fd, my_off_t newlength, myf MyFlags) if ( i < _this_block ) newpos = my_chsize(_fd_vector[i], _this_block * _raid_chunksize + (_rounds + 1) * - _raid_chunksize, - MyFlags); + _raid_chunksize, filler, MyFlags); else if ( i == _this_block ) newpos = my_chsize(_fd_vector[i], _this_block * _raid_chunksize + _rounds * _raid_chunksize + (newlength % _raid_chunksize), - MyFlags); + filler, MyFlags); else // this means: i > _this_block newpos = my_chsize(_fd_vector[i], _this_block * _raid_chunksize + _rounds * - _raid_chunksize, MyFlags); + _raid_chunksize, filler, MyFlags); if (newpos) DBUG_RETURN(1); } |