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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. include/myisammrg.h: Bug#45800 crash when replacing into a merge table and there is a duplicate Add a member to the st_mymerge_info structure that will store the duplicate key offset in the MERGE table. This offset will be the sum of the record offset of the MyISAM table within the MERGE table and the offset of the record within the MyISAM table. mysql-test/r/merge.result: Bug#45800 crash when replacing into a merge table and there is a duplicate Result file for the test case. mysql-test/t/merge.test: Bug#45800 crash when replacing into a merge table and there is a duplicate Added test case for both REPLACE and INSERT...ON DUPLICATE UPDATE. storage/myisammrg/ha_myisammrg.cc: Bug#45800 crash when replacing into a merge table and there is a duplicate The info method now will process the HA_STATUS_ERRKEY flag and will return the index and the offset of the duplicate key. storage/myisammrg/ha_myisammrg.h: Bug#45800 crash when replacing into a merge table and there is a duplicate Set the HA_DUPLICATE_POS flag to indicate that the duplicate key information is now available in the MERGE storage engine. storage/myisammrg/myrg_info.c: Bug#45800 crash when replacing into a merge table and there is a duplicate We modify the myrg_status function to return the position of the duplicate key. The duplicate key position in the MERGE table will be the MyISAM file_offset and the offset within the MyISAM table of the start position of the records.
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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