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A REPLACE in the MERGE engine is actually a REPLACE into one (FIRST or LAST) of the underlying MyISAM tables. So in effect the server works on the meta data of the MERGE table, while the real insert happens in the MyISAM table. The MERGE table has no index, while MyISAM has a unique index. When a REPLACE into a MERGE table ( and the REPLACE conflicts with a duplicate in a child table) is done, we try to access the duplicate key information for the MERGE table. This information actually does not exist, hence this results in a crash. The problem can be resolved by modifying the MERGE engine to provide us the duplicate key information directly, instead of just returning the MyISAM index number as the error key. Then the SQL layer (or "the server") does not try to access the key_info of the MERGE table, which does not exist. The current patch modifies the MERGE engine to provide the position for a record where a unique key violation occurs.
85 lines
2.9 KiB
C
85 lines
2.9 KiB
C
/* Copyright (C) 2000-2002 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 "myrg_def.h"
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ulonglong myrg_position(MYRG_INFO *info)
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{
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MYRG_TABLE *current_table;
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if (!(current_table = info->current_table) &&
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info->open_tables != info->end_table)
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current_table = info->open_tables;
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return current_table ?
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current_table->table->lastpos + current_table->file_offset :
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~(ulonglong) 0;
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}
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int myrg_status(MYRG_INFO *info,register MYMERGE_INFO *x,int flag)
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{
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MYRG_TABLE *current_table;
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DBUG_ENTER("myrg_status");
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if (!(current_table = info->current_table) &&
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info->open_tables != info->end_table)
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current_table = info->open_tables;
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x->recpos = info->current_table ?
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info->current_table->table->lastpos + info->current_table->file_offset :
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(ulong) -1L;
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if (flag != HA_STATUS_POS)
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{
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MYRG_TABLE *file;
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info->records=info->del=info->data_file_length=0;
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for (file=info->open_tables ; file != info->end_table ; file++)
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{
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file->file_offset=info->data_file_length;
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info->data_file_length+=file->table->s->state.state.data_file_length;
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info->records+=file->table->s->state.state.records;
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info->del+=file->table->s->state.state.del;
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DBUG_PRINT("info2",("table: %s, offset: %lu",
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file->table->filename,(ulong) file->file_offset));
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}
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x->records= info->records;
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x->deleted= info->del;
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x->data_file_length= info->data_file_length;
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x->reclength= info->reclength;
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x->options= info->options;
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if (current_table)
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{
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/*
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errkey is set to the index number of the myisam tables. But
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since the MERGE table can have less keys than the MyISAM
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tables, errkey cannot be be used as an index into the key_info
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on the server. This value will be overwritten with MAX_KEY by
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the MERGE engine.
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*/
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x->errkey= current_table->table->errkey;
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/*
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Calculate the position of the duplicate key to be the sum of the
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offset of the myisam file and the offset into the file at which
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the duplicate key is located.
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*/
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x->dupp_key_pos= current_table->file_offset + current_table->table->dupp_key_pos;
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}
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else
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{
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x->errkey= 0;
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x->dupp_key_pos= 0;
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}
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x->rec_per_key = info->rec_per_key_part;
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}
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DBUG_RETURN(0);
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}
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