mirror of
https://github.com/MariaDB/server.git
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2c4fa340cc
Fixed bugs in my last changeset that made MySQL hard to compile. Added mutex around some data that could cause table cache corruptions when using OPTIMIZE TABLE / REPAIR TABLE or automatic repair of MyISAM tables. Added mutex around some data in the slave start/stop code that could cause THD linked list corruptions Extended my_chsize() to allow one to specify a filler character. Extend vio_blocking to return the old state (This made some usage of this function much simpler) Added testing for some functions that they caller have got the required mutexes before calling the function. Use setrlimit() to ensure that we can write core file if one specifies --core-file. Added --slave-compressed-protocol Made 2 the minimum length for ft_min_word_len Added variables foreign_key_checks & unique_checks. Less logging from replication code (if not started with --log-warnings) Changed that SHOW INNODB STATUS requre the SUPER privilege More DBUG statements and a lot of new code comments
107 lines
3.5 KiB
C
107 lines
3.5 KiB
C
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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; either version 2 of the License, or
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(at your option) any later version.
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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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/*
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Functions for read record cacheing with myisam
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Used for reading dynamic/compressed records from datafile.
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Can fetch data directly from file (outside cache),
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if reading a small chunk straight before the cached part (with possible
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overlap).
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Can be explicitly asked not to use cache (by not setting READING_NEXT in
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flag) - useful for occasional out-of-cache reads, when the next read is
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expected to hit the cache again.
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Allows "partial read" errors in the record header (when READING_HEADER flag
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is set) - unread part is bzero'ed
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Note: out-of-cache reads are disabled for shared IO_CACHE's
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*/
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#include "myisamdef.h"
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int _mi_read_cache(IO_CACHE *info, byte *buff, my_off_t pos, uint length,
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int flag)
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{
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uint read_length,in_buff_length;
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my_off_t offset;
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char *in_buff_pos;
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DBUG_ENTER("_mi_read_cache");
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if (pos < info->pos_in_file && ! info->share)
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{
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read_length=length;
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if ((my_off_t) read_length > (my_off_t) (info->pos_in_file-pos))
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read_length=(uint) (info->pos_in_file-pos);
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info->seek_not_done=1;
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if (my_pread(info->file,buff,read_length,pos,MYF(MY_NABP)))
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DBUG_RETURN(1);
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if (!(length-=read_length))
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DBUG_RETURN(0);
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pos+=read_length;
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buff+=read_length;
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}
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if (pos >= info->pos_in_file &&
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(offset= (my_off_t) (pos - info->pos_in_file)) <
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(my_off_t) (info->read_end - info->request_pos))
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{
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in_buff_pos=info->request_pos+(uint) offset;
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in_buff_length= min(length,(uint) (info->read_end-in_buff_pos));
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memcpy(buff,info->request_pos+(uint) offset,(size_t) in_buff_length);
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if (!(length-=in_buff_length))
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DBUG_RETURN(0);
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pos+=in_buff_length;
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buff+=in_buff_length;
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}
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else
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in_buff_length=0;
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if (flag & READING_NEXT || info->share)
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{
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if (pos != (info->pos_in_file +
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(uint) (info->read_end - info->request_pos)))
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{
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info->pos_in_file=pos; /* Force start here */
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info->read_pos=info->read_end=info->request_pos; /* Everything used */
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info->seek_not_done=1;
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}
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else
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info->read_pos=info->read_end; /* All block used */
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if (!(*info->read_function)(info,buff,length))
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DBUG_RETURN(0);
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read_length=info->error;
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}
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else
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{
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info->seek_not_done=1;
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if ((read_length=my_pread(info->file,buff,length,pos,MYF(0))) == length)
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DBUG_RETURN(0);
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}
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if (!(flag & READING_HEADER) || (int) read_length == -1 ||
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read_length+in_buff_length < 3)
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{
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DBUG_PRINT("error",
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("Error %d reading next-multi-part block (Got %d bytes)",
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my_errno, (int) read_length));
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if (!my_errno || my_errno == -1)
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my_errno=HA_ERR_WRONG_IN_RECORD;
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DBUG_RETURN(1);
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}
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bzero(buff+read_length,MI_BLOCK_INFO_HEADER_LENGTH - in_buff_length -
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read_length);
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DBUG_RETURN(0);
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} /* _mi_read_cache */
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