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mariadb/sql/mf_iocache.cc
bk@work.mysql.com f4c589ff6c Import changeset
2000-07-31 21:29:14 +02:00

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/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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 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 */
/*
Cashing of files with only does (sequential) read or writes of fixed-
length records. A read isn't allowed to go over file-length. A read is ok
if it ends at file-length and next read can try to read after file-length
(and get a EOF-error).
Possibly use of asyncronic io.
macros for read and writes for faster io.
Used instead of FILE when reading or writing whole files.
This will make mf_rec_cache obsolete.
One can change info->pos_in_file to a higher value to skip bytes in file if
also info->rc_pos is set to info->rc_end.
If called through open_cached_file(), then the temporary file will
only be created if a write exeeds the file buffer or if one calls
flush_io_cache().
*/
#define MAP_TO_USE_RAID
#include "mysql_priv.h"
#include <mysys_err.h>
#ifdef HAVE_AIOWAIT
#include <errno.h>
static void my_aiowait(my_aio_result *result);
#endif
/* if cachesize == 0 then use default cachesize (from s-file) */
/* returns 0 if we have enough memory */
extern "C" {
int init_io_cache(IO_CACHE *info, File file, uint cachesize,
enum cache_type type, my_off_t seek_offset,
pbool use_async_io, myf cache_myflags)
{
uint min_cache;
DBUG_ENTER("init_io_cache");
DBUG_PRINT("enter",("type: %d pos: %ld",(int) type, (ulong) seek_offset));
/* There is no file in net_reading */
info->file= file;
if (!cachesize)
if (! (cachesize= my_default_record_cache_size))
DBUG_RETURN(1); /* No cache requested */
min_cache=use_async_io ? IO_SIZE*4 : IO_SIZE*2;
if (type == READ_CACHE)
{ /* Assume file isn't growing */
my_off_t file_pos,end_of_file;
if ((file_pos=my_tell(file,MYF(0)) == MY_FILEPOS_ERROR))
DBUG_RETURN(1);
end_of_file=my_seek(file,0L,MY_SEEK_END,MYF(0));
if (end_of_file < seek_offset)
end_of_file=seek_offset;
VOID(my_seek(file,file_pos,MY_SEEK_SET,MYF(0)));
if ((my_off_t) cachesize > end_of_file-seek_offset+IO_SIZE*2-1)
{
cachesize=(uint) (end_of_file-seek_offset)+IO_SIZE*2-1;
use_async_io=0; /* No nead to use async */
}
}
if ((int) type < (int) READ_NET)
{
for (;;)
{
cachesize=(uint) ((ulong) (cachesize + min_cache-1) &
(ulong) ~(min_cache-1));
if (cachesize < min_cache)
cachesize = min_cache;
if ((info->buffer=
(byte*) my_malloc(cachesize,
MYF((cache_myflags & ~ MY_WME) |
(cachesize == min_cache ? MY_WME : 0)))) != 0)
break; /* Enough memory found */
if (cachesize == min_cache)
DBUG_RETURN(2); /* Can't alloc cache */
cachesize= (uint) ((long) cachesize*3/4); /* Try with less memory */
}
}
else
info->buffer=0;
info->pos_in_file= seek_offset;
info->read_length=info->buffer_length=cachesize;
info->seek_not_done=test(file >= 0); /* Seek not done */
info->myflags=cache_myflags & ~(MY_NABP | MY_FNABP);
info->rc_request_pos=info->rc_pos=info->buffer;
if (type == READ_CACHE || type == READ_NET) /* the same logic */
{
info->rc_end=info->buffer; /* Nothing in cache */
}
else /* type == WRITE_CACHE */
{
info->rc_end=info->buffer+info->buffer_length- (seek_offset & (IO_SIZE-1));
}
info->end_of_file=(type == READ_NET) ? 0 : MY_FILEPOS_ERROR; /* May be changed by user */
info->type=type;
info->error=0;
info->read_function=(type == READ_NET) ? _my_b_net_read : _my_b_read; /* net | file */
#ifdef HAVE_AIOWAIT
if (use_async_io && ! my_disable_async_io)
{
DBUG_PRINT("info",("Using async io"));
info->read_length/=2;
info->read_function=_my_b_async_read;
}
info->inited=info->aio_result.pending=0;
#endif
DBUG_RETURN(0);
} /* init_io_cache */
/* Wait until current request is ready */
#ifdef HAVE_AIOWAIT
static void my_aiowait(my_aio_result *result)
{
if (result->pending)
{
struct aio_result_t *tmp;
for (;;)
{
if ((int) (tmp=aiowait((struct timeval *) 0)) == -1)
{
if (errno == EINTR)
continue;
DBUG_PRINT("error",("No aio request, error: %d",errno));
result->pending=0; /* Assume everythings is ok */
break;
}
((my_aio_result*) tmp)->pending=0;
if ((my_aio_result*) tmp == result)
break;
}
}
return;
}
#endif
/* Use this to reset cache to start or other type */
/* Some simple optimizing is done when reinit in current buffer */
my_bool reinit_io_cache(IO_CACHE *info, enum cache_type type,
my_off_t seek_offset,
pbool use_async_io __attribute__((unused)),
pbool clear_cache)
{
DBUG_ENTER("reinit_io_cache");
info->seek_not_done= test(info->file >= 0); /* Seek not done */
if (!clear_cache && seek_offset >= info->pos_in_file &&
seek_offset <= info->pos_in_file +
(uint) (info->rc_end - info->rc_request_pos))
{ /* use current buffer */
if (info->type == WRITE_CACHE && type == READ_CACHE)
{
info->rc_end=info->rc_pos;
info->end_of_file=my_b_tell(info);
}
else if (info->type == READ_CACHE && type == WRITE_CACHE)
info->rc_end=info->buffer+info->buffer_length;
info->rc_pos=info->rc_request_pos+(seek_offset-info->pos_in_file);
#ifdef HAVE_AIOWAIT
my_aiowait(&info->aio_result); /* Wait for outstanding req */
#endif
}
else
{
if (info->type == WRITE_CACHE && type == READ_CACHE)
info->end_of_file=my_b_tell(info);
if (flush_io_cache(info))
DBUG_RETURN(1);
info->pos_in_file=seek_offset;
info->rc_request_pos=info->rc_pos=info->buffer;
if (type == READ_CACHE || type == READ_NET)
{
info->rc_end=info->buffer; /* Nothing in cache */
}
else
{
info->rc_end=info->buffer+info->buffer_length-
(seek_offset & (IO_SIZE-1));
info->end_of_file=(type == READ_NET) ? 0 : MY_FILEPOS_ERROR;
}
}
info->type=type;
info->error=0;
info->read_function=(type == READ_NET) ? _my_b_net_read : _my_b_read;
#ifdef HAVE_AIOWAIT
if (type != READ_NET)
{
if (use_async_io && ! my_disable_async_io &&
((ulong) info->buffer_length <
(ulong) (info->end_of_file - seek_offset)))
{
info->read_length=info->buffer_length/2;
info->read_function=_my_b_async_read;
}
}
info->inited=0;
#endif
DBUG_RETURN(0);
} /* init_io_cache */
/* Read buffered. Returns 1 if can't read requested characters */
/* Returns 0 if record read */
int _my_b_read(register IO_CACHE *info, byte *Buffer, uint Count)
{
uint length,diff_length,left_length;
my_off_t max_length, pos_in_file;
memcpy(Buffer,info->rc_pos,
(size_t) (left_length=(uint) (info->rc_end-info->rc_pos)));
Buffer+=left_length;
Count-=left_length;
pos_in_file=info->pos_in_file+(uint) (info->rc_end - info->buffer);
if (info->seek_not_done)
{ /* File touched, do seek */
VOID(my_seek(info->file,pos_in_file,MY_SEEK_SET,MYF(0)));
info->seek_not_done=0;
}
diff_length=(uint) (pos_in_file & (IO_SIZE-1));
if (Count >= (uint) (IO_SIZE+(IO_SIZE-diff_length)))
{ /* Fill first intern buffer */
uint read_length;
if (info->end_of_file == pos_in_file)
{ /* End of file */
info->error=(int) left_length;
return 1;
}
length=(Count & (uint) ~(IO_SIZE-1))-diff_length;
if ((read_length=my_read(info->file,Buffer,(uint) length,info->myflags))
!= (uint) length)
{
info->error= read_length == (uint) -1 ? -1 :
(int) (read_length+left_length);
return 1;
}
Count-=length;
Buffer+=length;
pos_in_file+=length;
left_length+=length;
diff_length=0;
}
max_length=info->end_of_file - pos_in_file;
if (max_length > info->read_length-diff_length)
max_length=info->read_length-diff_length;
if (!max_length)
{
if (Count)
{
info->error= left_length; /* We only got this many char */
return 1;
}
length=0; /* Didn't read any chars */
}
else if ((length=my_read(info->file,info->buffer,(uint) max_length,
info->myflags)) < Count ||
length == (uint) -1)
{
if (length != (uint) -1)
memcpy(Buffer,info->buffer,(size_t) length);
info->error= length == (uint) -1 ? -1 : (int) (length+left_length);
return 1;
}
info->rc_pos=info->buffer+Count;
info->rc_end=info->buffer+length;
info->pos_in_file=pos_in_file;
memcpy(Buffer,info->buffer,(size_t) Count);
return 0;
}
/*
** Read buffered from the net.
** Returns 1 if can't read requested characters
** Returns 0 if record read
*/
int _my_b_net_read(register IO_CACHE *info, byte *Buffer,
uint Count __attribute__((unused)))
{
int read_length;
NET *net= &(current_thd)->net;
if (info->end_of_file)
return 1; /* because my_b_get (no _) takes 1 byte at a time */
read_length=my_net_read(net);
if (read_length == (int) packet_error)
{
info->error=(uint) -1;
return 1;
}
if (read_length == 0)
{
/* End of file from client */
info->end_of_file = 1; return 1;
}
/* to set up stuff for my_b_get (no _) */
info->rc_end = (info->rc_pos = (byte*) net->read_pos) + read_length;
Buffer[0] = info->rc_pos[0]; /* length is always 1 */
info->rc_pos++;
return 0;
}
#ifdef HAVE_AIOWAIT
int _my_b_async_read(register IO_CACHE *info, byte *Buffer, uint Count)
{
uint length,read_length,diff_length,left_length,use_length,org_Count;
my_off_t max_length;
my_off_t next_pos_in_file;
byte *read_buffer;
memcpy(Buffer,info->rc_pos,
(size_t) (left_length=(uint) (info->rc_end-info->rc_pos)));
Buffer+=left_length;
org_Count=Count;
Count-=left_length;
if (info->inited)
{ /* wait for read block */
info->inited=0; /* No more block to read */
my_aiowait(&info->aio_result); /* Wait for outstanding req */
if (info->aio_result.result.aio_errno)
{
if (info->myflags & MY_WME)
my_error(EE_READ, MYF(ME_BELL+ME_WAITTANG),
my_filename(info->file),
info->aio_result.result.aio_errno);
my_errno=info->aio_result.result.aio_errno;
info->error= -1;
return(1);
}
if (! (read_length = (uint) info->aio_result.result.aio_return) ||
read_length == (uint) -1)
{
my_errno=0; /* For testing */
info->error= (read_length == (uint) -1 ? -1 :
(int) (read_length+left_length));
return(1);
}
info->pos_in_file+=(uint) (info->rc_end - info->rc_request_pos);
if (info->rc_request_pos != info->buffer)
info->rc_request_pos=info->buffer;
else
info->rc_request_pos=info->buffer+info->read_length;
info->rc_pos=info->rc_request_pos;
next_pos_in_file=info->aio_read_pos+read_length;
/* Check if pos_in_file is changed
(_ni_read_cache may have skipped some bytes) */
if (info->aio_read_pos < info->pos_in_file)
{ /* Fix if skipped bytes */
if (info->aio_read_pos + read_length < info->pos_in_file)
{
read_length=0; /* Skipp block */
next_pos_in_file=info->pos_in_file;
}
else
{
my_off_t offset= (info->pos_in_file - info->aio_read_pos);
info->pos_in_file=info->aio_read_pos; /* Whe are here */
info->rc_pos=info->rc_request_pos+offset;
read_length-=offset; /* Bytes left from rc_pos */
}
}
#ifndef DBUG_OFF
if (info->aio_read_pos > info->pos_in_file)
{
my_errno=EINVAL;
return(info->read_length= -1);
}
#endif
/* Copy found bytes to buffer */
length=min(Count,read_length);
memcpy(Buffer,info->rc_pos,(size_t) length);
Buffer+=length;
Count-=length;
left_length+=length;
info->rc_end=info->rc_pos+read_length;
info->rc_pos+=length;
}
else
next_pos_in_file=(info->pos_in_file+ (uint)
(info->rc_end - info->rc_request_pos));
/* If reading large blocks, or first read or read with skipp */
if (Count)
{
if (next_pos_in_file == info->end_of_file)
{
info->error=(int) (read_length+left_length);
return 1;
}
VOID(my_seek(info->file,next_pos_in_file,MY_SEEK_SET,MYF(0)));
read_length=IO_SIZE*2- (uint) (next_pos_in_file & (IO_SIZE-1));
if (Count < read_length)
{ /* Small block, read to cache */
if ((read_length=my_read(info->file,info->rc_request_pos,
read_length, info->myflags)) == (uint) -1)
return info->error= -1;
use_length=min(Count,read_length);
memcpy(Buffer,info->rc_request_pos,(size_t) use_length);
info->rc_pos=info->rc_request_pos+Count;
info->rc_end=info->rc_request_pos+read_length;
info->pos_in_file=next_pos_in_file; /* Start of block in cache */
next_pos_in_file+=read_length;
if (Count != use_length)
{ /* Didn't find hole block */
if (info->myflags & (MY_WME | MY_FAE | MY_FNABP) && Count != org_Count)
my_error(EE_EOFERR, MYF(ME_BELL+ME_WAITTANG),
my_filename(info->file),my_errno);
info->error=(int) (read_length+left_length);
return 1;
}
}
else
{ /* Big block, don't cache it */
if ((read_length=my_read(info->file,Buffer,(uint) Count,info->myflags))
!= Count)
{
info->error= read_length == (uint) -1 ? -1 : read_length+left_length;
return 1;
}
info->rc_pos=info->rc_end=info->rc_request_pos;
info->pos_in_file=(next_pos_in_file+=Count);
}
}
/* Read next block with asyncronic io */
max_length=info->end_of_file - next_pos_in_file;
diff_length=(next_pos_in_file & (IO_SIZE-1));
if (max_length > (my_off_t) info->read_length - diff_length)
max_length= (my_off_t) info->read_length - diff_length;
if (info->rc_request_pos != info->buffer)
read_buffer=info->buffer;
else
read_buffer=info->buffer+info->read_length;
info->aio_read_pos=next_pos_in_file;
if (max_length)
{
info->aio_result.result.aio_errno=AIO_INPROGRESS; /* Marker for test */
DBUG_PRINT("aioread",("filepos: %ld length: %ld",
(ulong) next_pos_in_file,(ulong) max_length));
if (aioread(info->file,read_buffer,(int) max_length,
(my_off_t) next_pos_in_file,MY_SEEK_SET,
&info->aio_result.result))
{ /* Skipp async io */
my_errno=errno;
DBUG_PRINT("error",("got error: %d, aio_result: %d from aioread, async skipped",
errno, info->aio_result.result.aio_errno));
if (info->rc_request_pos != info->buffer)
{
bmove(info->buffer,info->rc_request_pos,
(uint) (info->rc_end - info->rc_pos));
info->rc_request_pos=info->buffer;
info->rc_pos-=info->read_length;
info->rc_end-=info->read_length;
}
info->read_length=info->buffer_length; /* Use hole buffer */
info->read_function=_my_b_read; /* Use normal IO_READ next */
}
else
info->inited=info->aio_result.pending=1;
}
return 0; /* Block read, async in use */
} /* _my_b_async_read */
#endif
/* Read one byte when buffer is empty */
int _my_b_get(IO_CACHE *info)
{
byte buff;
if ((*(info)->read_function)(info,&buff,1))
return my_b_EOF;
return (int) (uchar) buff;
}
/* Returns != 0 if error on write */
int _my_b_write(register IO_CACHE *info, const byte *Buffer, uint Count)
{
uint rest_length,length;
rest_length=(uint) (info->rc_end - info->rc_pos);
memcpy(info->rc_pos,Buffer,(size_t) rest_length);
Buffer+=rest_length;
Count-=rest_length;
info->rc_pos+=rest_length;
if (flush_io_cache(info))
return 1;
if (Count >= IO_SIZE)
{ /* Fill first intern buffer */
length=Count & (uint) ~(IO_SIZE-1);
if (info->seek_not_done)
{ /* File touched, do seek */
VOID(my_seek(info->file,info->pos_in_file,MY_SEEK_SET,MYF(0)));
info->seek_not_done=0;
}
if (my_write(info->file,Buffer,(uint) length,info->myflags | MY_NABP))
return info->error= -1;
Count-=length;
Buffer+=length;
info->pos_in_file+=length;
}
memcpy(info->rc_pos,Buffer,(size_t) Count);
info->rc_pos+=Count;
return 0;
}
/*
Write a block to disk where part of the data may be inside the record
buffer. As all write calls to the data goes through the cache,
we will never get a seek over the end of the buffer
*/
int my_block_write(register IO_CACHE *info, const byte *Buffer, uint Count,
my_off_t pos)
{
uint length;
int error=0;
if (pos < info->pos_in_file)
{
/* Of no overlap, write everything without buffering */
if (pos + Count <= info->pos_in_file)
return my_pwrite(info->file, Buffer, Count, pos,
info->myflags | MY_NABP);
/* Write the part of the block that is before buffer */
length= (uint) (info->pos_in_file - pos);
if (my_pwrite(info->file, Buffer, length, pos, info->myflags | MY_NABP))
info->error=error=-1;
Buffer+=length;
pos+= length;
Count-= length;
}
/* Check if we want to write inside the used part of the buffer.*/
length= (uint) (info->rc_end - info->buffer);
if (pos < info->pos_in_file + length)
{
uint offset= (uint) (pos - info->pos_in_file);
length-=offset;
if (length > Count)
length=Count;
memcpy(info->buffer+offset, Buffer, length);
Buffer+=length;
Count-= length;
/* Fix length of buffer if the new data was larger */
if (info->buffer+length > info->rc_pos)
info->rc_pos=info->buffer+length;
if (!Count)
return (error);
}
/* Write at the end of the current buffer; This is the normal case */
if (_my_b_write(info, Buffer, Count))
error= -1;
return error;
}
/* Flush write cache */
int flush_io_cache(IO_CACHE *info)
{
uint length;
DBUG_ENTER("flush_io_cache");
if (info->type == WRITE_CACHE)
{
if (info->file == -1)
{
if (real_open_cached_file(info))
DBUG_RETURN((info->error= -1));
}
if (info->rc_pos != info->buffer)
{
length=(uint) (info->rc_pos - info->buffer);
if (info->seek_not_done)
{ /* File touched, do seek */
VOID(my_seek(info->file,info->pos_in_file,MY_SEEK_SET,MYF(0)));
info->seek_not_done=0;
}
info->rc_pos=info->buffer;
info->pos_in_file+=length;
info->rc_end=(info->buffer+info->buffer_length-
(info->pos_in_file & (IO_SIZE-1)));
if (my_write(info->file,info->buffer,length,info->myflags | MY_NABP))
DBUG_RETURN((info->error= -1));
DBUG_RETURN(0);
}
}
#ifdef HAVE_AIOWAIT
else if (info->type != READ_NET)
{
my_aiowait(&info->aio_result); /* Wait for outstanding req */
info->inited=0;
}
#endif
DBUG_RETURN(0);
}
int end_io_cache(IO_CACHE *info)
{
int error=0;
DBUG_ENTER("end_io_cache");
if (info->buffer)
{
if (info->file != -1) /* File doesn't exist */
error=flush_io_cache(info);
my_free((gptr) info->buffer,MYF(MY_WME));
info->buffer=info->rc_pos=(byte*) 0;
}
DBUG_RETURN(error);
} /* end_io_cache */
}
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