mirror of
https://github.com/MariaDB/server.git
synced 2025-01-20 05:52:27 +01:00
4e138572a0
The problem appeared because the same values produced different hash during INSERT and SELECT for VARCHAR data type. Fix: VARCHAR required special treatment to avoid hashing of length bytes (leftmost one or two bytes) as well as trailing bytes beyond real length, which could contain garbage. Fix is done by introducing hash() - new method in the Field class. mysql-test/r/partition_innodb.result: Adding test case mysql-test/r/partition_pruning.result: Fixing test results (results differ due to changes in hash function) mysql-test/t/partition_innodb.test: Adding test case sql/field.cc: Adding generic hash() method, and a special method for VARCHAR. sql/field.h: Adding prototypes for new methods sql/key.cc: Mark columns for write before executinf of set_key_image(). Thanks for Mikael for suggesting this fix. sql/sql_partition.cc: Removing old hash code. Using new methid field->hash() instead.
531 lines
15 KiB
C++
531 lines
15 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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/* Functions to handle keys and fields in forms */
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#include "mysql_priv.h"
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/*
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** Search after with key field is. If no key starts with field test
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** if field is part of some key.
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**
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** returns number of key. keylength is set to length of key before
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** (not including) field
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** Used when calculating key for NEXT_NUMBER
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*/
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int find_ref_key(KEY *key, uint key_count, Field *field, uint *key_length)
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{
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reg2 int i;
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reg3 KEY *key_info;
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uint fieldpos;
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fieldpos= field->offset();
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/* Test if some key starts as fieldpos */
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for (i= 0, key_info= key ;
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i < (int) key_count ;
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i++, key_info++)
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{
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if (key_info->key_part[0].offset == fieldpos)
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{ /* Found key. Calc keylength */
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*key_length=0;
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return(i); /* Use this key */
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}
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}
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/* Test if some key contains fieldpos */
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for (i= 0, key_info= key;
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i < (int) key_count ;
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i++, key_info++)
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{
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uint j;
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KEY_PART_INFO *key_part;
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*key_length=0;
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for (j=0, key_part=key_info->key_part ;
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j < key_info->key_parts ;
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j++, key_part++)
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{
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if (key_part->offset == fieldpos)
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return(i); /* Use this key */
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*key_length+=key_part->store_length;
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}
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}
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return(-1); /* No key is ok */
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}
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/*
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Copy part of a record that forms a key or key prefix to a buffer.
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SYNOPSIS
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key_copy()
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to_key buffer that will be used as a key
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from_record full record to be copied from
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key_info descriptor of the index
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key_length specifies length of all keyparts that will be copied
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DESCRIPTION
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The function takes a complete table record (as e.g. retrieved by
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handler::index_read()), and a description of an index on the same table,
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and extracts the first key_length bytes of the record which are part of a
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key into to_key. If length == 0 then copy all bytes from the record that
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form a key.
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RETURN
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None
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*/
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void key_copy(byte *to_key, byte *from_record, KEY *key_info, uint key_length)
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{
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uint length;
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KEY_PART_INFO *key_part;
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if (key_length == 0)
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key_length= key_info->key_length;
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for (key_part= key_info->key_part; (int) key_length > 0; key_part++)
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{
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if (key_part->null_bit)
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{
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*to_key++= test(from_record[key_part->null_offset] &
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key_part->null_bit);
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key_length--;
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}
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if (key_part->type == HA_KEYTYPE_BIT)
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{
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Field_bit *field= (Field_bit *) (key_part->field);
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if (field->bit_len)
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{
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uchar bits= get_rec_bits((uchar*) from_record +
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key_part->null_offset +
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(key_part->null_bit == 128),
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field->bit_ofs, field->bit_len);
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*to_key++= bits;
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key_length--;
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}
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}
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if (key_part->key_part_flag & HA_BLOB_PART)
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{
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char *pos;
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ulong blob_length= ((Field_blob*) key_part->field)->get_length();
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key_length-= HA_KEY_BLOB_LENGTH;
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((Field_blob*) key_part->field)->get_ptr(&pos);
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length=min(key_length, key_part->length);
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set_if_smaller(blob_length, length);
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int2store(to_key, (uint) blob_length);
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to_key+= HA_KEY_BLOB_LENGTH; // Skip length info
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memcpy(to_key, pos, blob_length);
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}
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else if (key_part->key_part_flag & HA_VAR_LENGTH_PART)
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{
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key_length-= HA_KEY_BLOB_LENGTH;
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length= min(key_length, key_part->length);
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key_part->field->get_key_image((char *) to_key, length, Field::itRAW);
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to_key+= HA_KEY_BLOB_LENGTH;
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}
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else
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{
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length= min(key_length, key_part->length);
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memcpy(to_key, from_record + key_part->offset, (size_t) length);
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}
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to_key+= length;
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key_length-= length;
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}
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}
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/*
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Restore a key from some buffer to record.
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SYNOPSIS
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key_restore()
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to_record record buffer where the key will be restored to
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from_key buffer that contains a key
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key_info descriptor of the index
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key_length specifies length of all keyparts that will be restored
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DESCRIPTION
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This function converts a key into record format. It can be used in cases
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when we want to return a key as a result row.
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RETURN
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None
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*/
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void key_restore(byte *to_record, byte *from_key, KEY *key_info,
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uint key_length)
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{
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uint length;
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KEY_PART_INFO *key_part;
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if (key_length == 0)
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{
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key_length= key_info->key_length;
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}
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for (key_part= key_info->key_part ; (int) key_length > 0 ; key_part++)
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{
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if (key_part->null_bit)
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{
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if (*from_key++)
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to_record[key_part->null_offset]|= key_part->null_bit;
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else
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to_record[key_part->null_offset]&= ~key_part->null_bit;
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key_length--;
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}
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if (key_part->type == HA_KEYTYPE_BIT)
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{
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Field_bit *field= (Field_bit *) (key_part->field);
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if (field->bit_len)
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{
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uchar bits= *(from_key + key_part->length -
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field->pack_length_in_rec() - 1);
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set_rec_bits(bits, to_record + key_part->null_offset +
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(key_part->null_bit == 128),
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field->bit_ofs, field->bit_len);
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}
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}
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if (key_part->key_part_flag & HA_BLOB_PART)
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{
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uint blob_length= uint2korr(from_key);
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from_key+= HA_KEY_BLOB_LENGTH;
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key_length-= HA_KEY_BLOB_LENGTH;
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((Field_blob*) key_part->field)->set_ptr((ulong) blob_length,
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(char*) from_key);
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length= key_part->length;
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}
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else if (key_part->key_part_flag & HA_VAR_LENGTH_PART)
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{
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my_bitmap_map *old_map;
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key_length-= HA_KEY_BLOB_LENGTH;
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length= min(key_length, key_part->length);
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old_map= dbug_tmp_use_all_columns(key_part->field->table,
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key_part->field->table->write_set);
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key_part->field->set_key_image((char *) from_key, length);
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dbug_tmp_restore_column_map(key_part->field->table->write_set, old_map);
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from_key+= HA_KEY_BLOB_LENGTH;
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}
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else
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{
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length= min(key_length, key_part->length);
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memcpy(to_record + key_part->offset, from_key, (size_t) length);
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}
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from_key+= length;
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key_length-= length;
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}
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}
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/*
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Compare if a key has changed
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SYNOPSIS
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key_cmp_if_same()
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table TABLE
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key key to compare to row
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idx Index used
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key_length Length of key
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NOTES
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In theory we could just call field->cmp() for all field types,
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but as we are only interested if a key has changed (not if the key is
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larger or smaller than the previous value) we can do things a bit
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faster by using memcmp() instead.
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RETURN
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0 If key is equal
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1 Key has changed
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*/
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bool key_cmp_if_same(TABLE *table,const byte *key,uint idx,uint key_length)
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{
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uint store_length;
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KEY_PART_INFO *key_part;
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const byte *key_end= key + key_length;;
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for (key_part=table->key_info[idx].key_part;
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key < key_end ;
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key_part++, key+= store_length)
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{
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uint length;
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store_length= key_part->store_length;
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if (key_part->null_bit)
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{
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if (*key != test(table->record[0][key_part->null_offset] &
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key_part->null_bit))
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return 1;
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if (*key)
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continue;
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key++;
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store_length--;
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}
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if (key_part->key_part_flag & (HA_BLOB_PART | HA_VAR_LENGTH_PART |
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HA_BIT_PART))
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{
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if (key_part->field->key_cmp(key, key_part->length))
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return 1;
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continue;
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}
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length= min((uint) (key_end-key), store_length);
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if (!(key_part->key_type & (FIELDFLAG_NUMBER+FIELDFLAG_BINARY+
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FIELDFLAG_PACK)))
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{
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CHARSET_INFO *cs= key_part->field->charset();
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uint char_length= key_part->length / cs->mbmaxlen;
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const byte *pos= table->record[0] + key_part->offset;
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if (length > char_length)
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{
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char_length= my_charpos(cs, pos, pos + length, char_length);
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set_if_smaller(char_length, length);
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}
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if (cs->coll->strnncollsp(cs,
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(const uchar*) key, length,
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(const uchar*) pos, char_length, 0))
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return 1;
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continue;
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}
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if (memcmp(key,table->record[0]+key_part->offset,length))
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return 1;
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}
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return 0;
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}
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/*
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unpack key-fields from record to some buffer
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SYNOPSIS
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key_unpack()
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to Store value here in an easy to read form
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table Table to use
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idx Key number
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NOTES
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This is used mainly to get a good error message
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We temporary change the column bitmap so that all columns are readable.
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*/
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void key_unpack(String *to,TABLE *table,uint idx)
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{
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KEY_PART_INFO *key_part,*key_part_end;
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Field *field;
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String tmp;
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my_bitmap_map *old_map= dbug_tmp_use_all_columns(table, table->read_set);
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DBUG_ENTER("key_unpack");
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to->length(0);
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for (key_part=table->key_info[idx].key_part,key_part_end=key_part+
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table->key_info[idx].key_parts ;
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key_part < key_part_end;
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key_part++)
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{
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if (to->length())
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to->append('-');
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if (key_part->null_bit)
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{
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if (table->record[0][key_part->null_offset] & key_part->null_bit)
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{
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to->append(STRING_WITH_LEN("NULL"));
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continue;
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}
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}
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if ((field=key_part->field))
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{
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field->val_str(&tmp);
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if (key_part->length < field->pack_length())
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tmp.length(min(tmp.length(),key_part->length));
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to->append(tmp);
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}
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else
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to->append(STRING_WITH_LEN("???"));
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}
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dbug_tmp_restore_column_map(table->read_set, old_map);
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DBUG_VOID_RETURN;
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}
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/*
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Return 1 if any field in a list is part of key or the key uses a field
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that is automaticly updated (like a timestamp)
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*/
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bool check_if_key_used(TABLE *table, uint idx, List<Item> &fields)
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{
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List_iterator_fast<Item> f(fields);
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KEY_PART_INFO *key_part,*key_part_end;
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for (key_part=table->key_info[idx].key_part,key_part_end=key_part+
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table->key_info[idx].key_parts ;
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key_part < key_part_end;
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key_part++)
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{
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Item_field *field;
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if (key_part->field == table->timestamp_field)
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return 1; // Can't be used for update
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f.rewind();
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while ((field=(Item_field*) f++))
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{
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if (key_part->field->eq(field->field))
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return 1;
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}
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}
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/*
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If table handler has primary key as part of the index, check that primary
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key is not updated
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*/
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if (idx != table->s->primary_key && table->s->primary_key < MAX_KEY &&
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(table->file->ha_table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX))
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return check_if_key_used(table, table->s->primary_key, fields);
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return 0;
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}
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/*
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Compare key in row to a given key
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SYNOPSIS
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key_cmp()
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key_part Key part handler
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key Key to compare to value in table->record[0]
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key_length length of 'key'
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RETURN
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The return value is SIGN(key_in_row - range_key):
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0 Key is equal to range or 'range' == 0 (no range)
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-1 Key is less than range
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1 Key is larger than range
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*/
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int key_cmp(KEY_PART_INFO *key_part, const byte *key, uint key_length)
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{
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uint store_length;
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for (const byte *end=key + key_length;
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key < end;
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key+= store_length, key_part++)
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{
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int cmp;
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store_length= key_part->store_length;
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if (key_part->null_bit)
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{
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/* This key part allows null values; NULL is lower than everything */
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register bool field_is_null= key_part->field->is_null();
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if (*key) // If range key is null
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{
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/* the range is expecting a null value */
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if (!field_is_null)
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return 1; // Found key is > range
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/* null -- exact match, go to next key part */
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continue;
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}
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else if (field_is_null)
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return -1; // NULL is less than any value
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key++; // Skip null byte
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store_length--;
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}
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if ((cmp=key_part->field->key_cmp((byte*) key, key_part->length)) < 0)
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return -1;
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if (cmp > 0)
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return 1;
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}
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return 0; // Keys are equal
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}
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/*
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Compare two records in index order
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SYNOPSIS
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key_rec_cmp()
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key Index information
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rec0 Pointer to table->record[0]
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first_rec Pointer to record compare with
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second_rec Pointer to record compare against first_rec
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DESCRIPTION
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This method is set-up such that it can be called directly from the
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priority queue and it is attempted to be optimised as much as possible
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since this will be called O(N * log N) times while performing a merge
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sort in various places in the code.
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We retrieve the pointer to table->record[0] using the fact that key_parts
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have an offset making it possible to calculate the start of the record.
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We need to get the diff to the compared record since none of the records
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being compared are stored in table->record[0].
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We first check for NULL values, if there are no NULL values we use
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a compare method that gets two field pointers and a max length
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and return the result of the comparison.
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*/
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int key_rec_cmp(void *key, byte *first_rec, byte *second_rec)
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{
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KEY *key_info= (KEY*)key;
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uint key_parts= key_info->key_parts, i= 0;
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KEY_PART_INFO *key_part= key_info->key_part;
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char *rec0= key_part->field->ptr - key_part->offset;
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my_ptrdiff_t first_diff= first_rec - (byte*)rec0, sec_diff= second_rec - (byte*)rec0;
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int result= 0;
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DBUG_ENTER("key_rec_cmp");
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do
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{
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Field *field= key_part->field;
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if (key_part->null_bit)
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{
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/* The key_part can contain NULL values */
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bool first_is_null= field->is_null_in_record_with_offset(first_diff);
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bool sec_is_null= field->is_null_in_record_with_offset(sec_diff);
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/*
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NULL is smaller then everything so if first is NULL and the other
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not then we know that we should return -1 and for the opposite
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we should return +1. If both are NULL then we call it equality
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although it is a strange form of equality, we have equally little
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information of the real value.
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*/
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if (!first_is_null)
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{
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if (!sec_is_null)
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; /* Fall through, no NULL fields */
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else
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{
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DBUG_RETURN(+1);
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}
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}
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else if (!sec_is_null)
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|
{
|
|
DBUG_RETURN(-1);
|
|
}
|
|
else
|
|
goto next_loop; /* Both were NULL */
|
|
}
|
|
/*
|
|
No null values in the fields
|
|
We use the virtual method cmp_max with a max length parameter.
|
|
For most field types this translates into a cmp without
|
|
max length. The exceptions are the BLOB and VARCHAR field types
|
|
that take the max length into account.
|
|
*/
|
|
result= field->cmp_max(field->ptr+first_diff, field->ptr+sec_diff,
|
|
key_part->length);
|
|
next_loop:
|
|
key_part++;
|
|
} while (!result && ++i < key_parts);
|
|
DBUG_RETURN(result);
|
|
}
|