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Diffstat (limited to 'sql/key.cc')
| -rw-r--r-- | sql/key.cc | 898 |
1 files changed, 898 insertions, 0 deletions
diff --git a/sql/key.cc b/sql/key.cc new file mode 100644 index 00000000..79f1c55b --- /dev/null +++ b/sql/key.cc @@ -0,0 +1,898 @@ +/* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. + Copyright (c) 2018, 2020, MariaDB + + 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; version 2 of the License. + + 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */ + + +/* Functions to handle keys and fields in forms */ + +#include "mariadb.h" +#include "sql_priv.h" +#include "key.h" // key_rec_cmp +#include "field.h" // Field + +/* + Search after a key that starts with 'field' + + SYNOPSIS + find_ref_key() + key First key to check + key_count How many keys to check + record Start of record + field Field to search after + key_length On partial match, contains length of fields before + field + keypart key part # of a field + + NOTES + Used when calculating key for NEXT_NUMBER + + IMPLEMENTATION + If no key starts with field test if field is part of some key. If we find + one, then return first key and set key_length to the number of bytes + preceding 'field'. + + RETURN + -1 field is not part of the key + # Key part for key matching key. + key_length is set to length of key before (not including) field +*/ + +int find_ref_key(KEY *key, uint key_count, uchar *record, Field *field, + uint *key_length, uint *keypart) +{ + int i; + KEY *key_info; + uint fieldpos; + + fieldpos= field->offset(record); + + /* Test if some key starts as fieldpos */ + for (i= 0, key_info= key ; + i < (int) key_count ; + i++, key_info++) + { + if (key_info->key_part[0].offset == fieldpos && + key_info->key_part[0].field->type() != MYSQL_TYPE_BIT) + { /* Found key. Calc keylength */ + *key_length= *keypart= 0; + return i; /* Use this key */ + } + } + + /* Test if some key contains fieldpos */ + for (i= 0, key_info= key; + i < (int) key_count ; + i++, key_info++) + { + uint j; + KEY_PART_INFO *key_part; + *key_length=0; + for (j=0, key_part=key_info->key_part ; + j < key_info->user_defined_key_parts ; + j++, key_part++) + { + if (key_part->offset == fieldpos && + key_part->field->type() != MYSQL_TYPE_BIT) + { + *keypart= j; + return i; /* Use this key */ + } + *key_length+= key_part->store_length; + } + } + return(-1); /* No key is ok */ +} + + +/** + Copy part of a record that forms a key or key prefix to a buffer. + + The function takes a complete table record (as e.g. retrieved by + handler::index_read()), and a description of an index on the same table, + and extracts the first key_length bytes of the record which are part of a + key into to_key. If length == 0 then copy all bytes from the record that + form a key. + + @param to_key buffer that will be used as a key + @param from_record full record to be copied from + @param key_info descriptor of the index + @param key_length specifies length of all keyparts that will be copied + @param with_zerofill skipped bytes in the key buffer to be filled with 0 +*/ + +void key_copy(uchar *to_key, const uchar *from_record, const KEY *key_info, + uint key_length, bool with_zerofill) +{ + uint length; + KEY_PART_INFO *key_part; + + if (key_length == 0) + key_length= key_info->key_length; + for (key_part= key_info->key_part; + (int) key_length > 0; + key_part++, to_key+= length, key_length-= length) + { + if (key_part->null_bit) + { + *to_key++= MY_TEST(from_record[key_part->null_offset] & + key_part->null_bit); + key_length--; + if (to_key[-1]) + { + /* + Don't copy data for null values + The -1 below is to subtract the null byte which is already handled + */ + length= MY_MIN(key_length, uint(key_part->store_length)-1); + if (with_zerofill) + bzero((char*) to_key, length); + continue; + } + } + auto *from_ptr= key_part->field->ptr_in_record(from_record); + if (key_part->key_part_flag & HA_BLOB_PART || + key_part->key_part_flag & HA_VAR_LENGTH_PART) + { + key_length-= HA_KEY_BLOB_LENGTH; + length= MY_MIN(key_length, key_part->length); + uint bytes= key_part->field->get_key_image(to_key, length, from_ptr, + key_info->flags & HA_SPATIAL ? Field::itMBR : Field::itRAW); + if (with_zerofill && bytes < length) + bzero((char*) to_key + bytes, length - bytes); + to_key+= HA_KEY_BLOB_LENGTH; + } + else + { + length= MY_MIN(key_length, key_part->length); + Field *field= key_part->field; + CHARSET_INFO *cs= field->charset(); + uint bytes= field->get_key_image(to_key, length, from_ptr, Field::itRAW); + if (bytes < length) + cs->fill((char*) to_key + bytes, length - bytes, ' '); + } + } +} + + +/** + Restore a key from some buffer to record. + + This function converts a key into record format. It can be used in cases + when we want to return a key as a result row. + + @param to_record record buffer where the key will be restored to + @param from_key buffer that contains a key + @param key_info descriptor of the index + @param key_length specifies length of all keyparts that will be restored +*/ + +void key_restore(uchar *to_record, const uchar *from_key, KEY *key_info, + uint key_length) +{ + uint length; + KEY_PART_INFO *key_part; + + if (key_length == 0) + { + key_length= key_info->key_length; + } + for (key_part= key_info->key_part ; + (int) key_length > 0 ; + key_part++, from_key+= length, key_length-= length) + { + uchar used_uneven_bits= 0; + if (key_part->null_bit) + { + bool null_value; + if ((null_value= *from_key++)) + to_record[key_part->null_offset]|= key_part->null_bit; + else + to_record[key_part->null_offset]&= ~key_part->null_bit; + key_length--; + if (null_value) + { + /* + Don't copy data for null bytes + The -1 below is to subtract the null byte which is already handled + */ + length= MY_MIN(key_length, uint(key_part->store_length)-1); + continue; + } + } + if (key_part->type == HA_KEYTYPE_BIT) + { + Field_bit *field= (Field_bit *) (key_part->field); + if (field->bit_len) + { + uchar bits= *(from_key + key_part->length - + field->pack_length_in_rec() - 1); + set_rec_bits(bits, to_record + key_part->null_offset + + (key_part->null_bit == 128), + field->bit_ofs, field->bit_len); + /* we have now used the byte with 'uneven' bits */ + used_uneven_bits= 1; + } + } + if (key_part->key_part_flag & HA_BLOB_PART) + { + /* + This in fact never happens, as we have only partial BLOB + keys yet anyway, so it's difficult to find any sense to + restore the part of a record. + Maybe this branch is to be removed, but now we + have to ignore GCov compaining. + */ + uint blob_length= uint2korr(from_key); + Field_blob *field= (Field_blob*) key_part->field; + from_key+= HA_KEY_BLOB_LENGTH; + key_length-= HA_KEY_BLOB_LENGTH; + field->set_ptr_offset(to_record - field->table->record[0], + (ulong) blob_length, from_key); + length= key_part->length; + } + else if (key_part->key_part_flag & HA_VAR_LENGTH_PART) + { + Field *field= key_part->field; + my_ptrdiff_t ptrdiff= to_record - field->table->record[0]; + field->move_field_offset(ptrdiff); + key_length-= HA_KEY_BLOB_LENGTH; + length= MY_MIN(key_length, key_part->length); + MY_BITMAP *old_map= dbug_tmp_use_all_columns(field->table, &field->table->write_set); + field->set_key_image(from_key, length); + dbug_tmp_restore_column_map(&field->table->write_set, old_map); + from_key+= HA_KEY_BLOB_LENGTH; + field->move_field_offset(-ptrdiff); + } + else + { + length= MY_MIN(key_length, key_part->length); + /* skip the byte with 'uneven' bits, if used */ + memcpy(to_record + key_part->offset, from_key + used_uneven_bits + , (size_t) length - used_uneven_bits); + } + } +} + + +/** + Compare if a key has changed. + + @param table TABLE + @param key key to compare to row + @param idx Index used + @param key_length Length of key + + @note + In theory we could just call field->cmp() for all field types, + but as we are only interested if a key has changed (not if the key is + larger or smaller than the previous value) we can do things a bit + faster by using memcmp() instead. + + @retval + 0 If key is equal + @retval + 1 Key has changed +*/ + +bool key_cmp_if_same(TABLE *table,const uchar *key,uint idx,uint key_length) +{ + uint store_length; + KEY_PART_INFO *key_part; + const uchar *key_end= key + key_length;; + + for (key_part=table->key_info[idx].key_part; + key < key_end ; + key_part++, key+= store_length) + { + uint length; + store_length= key_part->store_length; + + if (key_part->null_bit) + { + if (*key != MY_TEST(table->record[0][key_part->null_offset] & + key_part->null_bit)) + return 1; + if (*key) + continue; + key++; + store_length--; + } + if (!(key_part->key_part_flag & HA_CAN_MEMCMP)) + { + if (key_part->field->key_cmp(key, key_part->length)) + return 1; + continue; + } + length= MY_MIN((uint) (key_end-key), store_length); + if (!(key_part->key_type & (FIELDFLAG_NUMBER+FIELDFLAG_BINARY+ + FIELDFLAG_PACK))) + { + CHARSET_INFO *cs= key_part->field->charset(); + size_t char_length= key_part->length / cs->mbmaxlen; + const uchar *pos= table->record[0] + key_part->offset; + if (length > char_length) + { + char_length= cs->charpos(pos, pos + length, char_length); + set_if_smaller(char_length, length); + } + if (cs->strnncollsp(key, length, pos, char_length)) + return 1; + continue; + } + if (memcmp(key,table->record[0]+key_part->offset,length)) + return 1; + } + return 0; +} + + +/** + Unpack a field and append it. + + @param[inout] to String to append the field contents to. + @param field Field to unpack. + @param rec Record which contains the field data. + @param max_length Maximum length of field to unpack + or 0 for unlimited. + @param prefix_key The field is used as a prefix key. +*/ + +void field_unpack(String *to, Field *field, const uchar *rec, uint max_length, + bool prefix_key) +{ + String tmp; + DBUG_ENTER("field_unpack"); + if (!max_length) + max_length= field->pack_length(); + if (field) + { + if (field->is_null()) + { + to->append(STRING_WITH_LEN("NULL")); + DBUG_VOID_RETURN; + } + CHARSET_INFO *cs= field->charset(); + field->val_str(&tmp); + /* + For BINARY(N) strip trailing zeroes to make + the error message nice-looking + */ + if (field->binary() && field->type() == MYSQL_TYPE_STRING && tmp.length()) + { + const char *tmp_end= tmp.ptr() + tmp.length(); + while (tmp_end > tmp.ptr() && !*--tmp_end) ; + tmp.length((uint32)(tmp_end - tmp.ptr() + 1)); + } + if (cs->mbmaxlen > 1 && prefix_key) + { + /* + Prefix key, multi-byte charset. + For the columns of type CHAR(N), the above val_str() + call will return exactly "key_part->length" bytes, + which can break a multi-byte characters in the middle. + Align, returning not more than "char_length" characters. + */ + size_t charpos, char_length= max_length / cs->mbmaxlen; + if ((charpos= cs->charpos(tmp.ptr(), + tmp.ptr() + tmp.length(), + char_length)) < tmp.length()) + tmp.length(charpos); + } + if (max_length < field->pack_length()) + tmp.length(MY_MIN(tmp.length(),max_length)); + ErrConvString err(&tmp); + to->append(err.ptr()); + } + else + to->append(STRING_WITH_LEN("???")); + DBUG_VOID_RETURN; +} + + +/* + unpack key-fields from record to some buffer. + + This is used mainly to get a good error message. We temporary + change the column bitmap so that all columns are readable. + + @param + to Store value here in an easy to read form + @param + table Table to use + @param + key Key +*/ + +void key_unpack(String *to, TABLE *table, KEY *key) +{ + MY_BITMAP *old_map= dbug_tmp_use_all_columns(table, &table->read_set); + DBUG_ENTER("key_unpack"); + + to->length(0); + KEY_PART_INFO *key_part_end= key->key_part + key->user_defined_key_parts; + for (KEY_PART_INFO *key_part= key->key_part; + key_part < key_part_end; + key_part++) + { + if (key_part->field->invisible > INVISIBLE_USER) + continue; + if (to->length()) + to->append('-'); + if (key_part->null_bit) + { + if (table->record[0][key_part->null_offset] & key_part->null_bit) + { + to->append(STRING_WITH_LEN("NULL")); + continue; + } + } + field_unpack(to, key_part->field, table->record[0], key_part->length, + MY_TEST(key_part->key_part_flag & HA_PART_KEY_SEG)); + } + dbug_tmp_restore_column_map(&table->read_set, old_map); + DBUG_VOID_RETURN; +} + + +/* + Check if key uses field that is marked in passed field bitmap. + + SYNOPSIS + is_key_used() + table TABLE object with which keys and fields are associated. + idx Key to be checked. + fields Bitmap of fields to be checked. + + NOTE + This function uses TABLE::tmp_set bitmap so the caller should care + about saving/restoring its state if it also uses this bitmap. + + RETURN VALUE + TRUE Key uses field from bitmap + FALSE Otherwise +*/ + +bool is_key_used(TABLE *table, uint idx, const MY_BITMAP *fields) +{ + table->mark_index_columns(idx, &table->tmp_set); + return bitmap_is_overlapping(&table->tmp_set, fields); +} + + +/** + Compare key in row to a given key. + + @param key_part Key part handler + @param key Key to compare to value in table->record[0] + @param key_length length of 'key' + + @return + The return value is SIGN(key_in_row - range_key): + - 0 Key is equal to range or 'range' == 0 (no range) + - -1 Key is less than range + - 1 Key is larger than range +*/ + +int key_cmp(KEY_PART_INFO *key_part, const uchar *key, uint key_length) +{ + uint store_length; + + for (const uchar *end=key + key_length; + key < end; + key+= store_length, key_part++) + { + int cmp; + store_length= key_part->store_length; + if (key_part->null_bit) + { + /* This key part allows null values; NULL is lower than everything */ + bool field_is_null= key_part->field->is_null(); + if (*key) // If range key is null + { + /* the range is expecting a null value */ + if (!field_is_null) + return 1; // Found key is > range + /* null -- exact match, go to next key part */ + continue; + } + else if (field_is_null) + return -1; // NULL is less than any value + key++; // Skip null byte + store_length--; + } + if ((cmp=key_part->field->key_cmp(key, key_part->length)) < 0) + return -1; + if (cmp > 0) + return 1; + } + return 0; // Keys are equal +} + + +/** + Compare two records in index order. + + This method is set-up such that it can be called directly from the + priority queue and it is attempted to be optimised as much as possible + since this will be called O(N * log N) times while performing a merge + sort in various places in the code. + + We retrieve the pointer to table->record[0] using the fact that key_parts + have an offset making it possible to calculate the start of the record. + We need to get the diff to the compared record since none of the records + being compared are stored in table->record[0]. + + We first check for NULL values, if there are no NULL values we use + a compare method that gets two field pointers and a max length + and return the result of the comparison. + + key is a null terminated array, since in some cases (clustered + primary key) it must compare more than one index. + + @param key Null terminated array of index information + @param first_rec Pointer to record compare with + @param second_rec Pointer to record compare against first_rec + + @return Return value is SIGN(first_rec - second_rec) + @retval 0 Keys are equal + @retval -1 second_rec is greater than first_rec + @retval +1 first_rec is greater than second_rec +*/ + +int key_rec_cmp(void *key_p, uchar *first_rec, uchar *second_rec) +{ + KEY **key= (KEY**) key_p; + KEY *key_info= *(key++); // Start with first key + uint key_parts, key_part_num; + KEY_PART_INFO *key_part= key_info->key_part; + uchar *rec0= key_part->field->ptr - key_part->offset; + my_ptrdiff_t first_diff= first_rec - rec0, sec_diff= second_rec - rec0; + int result= 0; + Field *field; + DBUG_ENTER("key_rec_cmp"); + + /* loop over all given keys */ + do + { + key_parts= key_info->user_defined_key_parts; + key_part= key_info->key_part; + key_part_num= 0; + + /* loop over every key part */ + do + { + field= key_part->field; + + if (key_part->null_bit) + { + /* The key_part can contain NULL values */ + bool first_is_null= field->is_real_null(first_diff); + bool sec_is_null= field->is_real_null(sec_diff); + /* + NULL is smaller then everything so if first is NULL and the other + not then we know that we should return -1 and for the opposite + we should return +1. If both are NULL then we call it equality + although it is a strange form of equality, we have equally little + information of the real value. + */ + if (!first_is_null) + { + if (!sec_is_null) + ; /* Fall through, no NULL fields */ + else + { + DBUG_RETURN(+1); + } + } + else if (!sec_is_null) + { + 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. + */ + if ((result= field->cmp_prefix(field->ptr+first_diff, field->ptr+sec_diff, + key_part->length))) + DBUG_RETURN(result); +next_loop: + key_part++; + key_part_num++; + } while (key_part_num < key_parts); /* this key is done */ + + key_info= *(key++); + } while (key_info); /* no more keys to test */ + DBUG_RETURN(0); +} + + +/* + Compare two key tuples. + + @brief + Compare two key tuples, i.e. two key values in KeyTupleFormat. + + @param part KEY_PART_INFO with key description + @param key1 First key to compare + @param key2 Second key to compare + @param tuple_length Length of key1 (and key2, they are the same) in bytes. + + @return + @retval 0 key1 == key2 + @retval -1 key1 < key2 + @retval +1 key1 > key2 +*/ + +int key_tuple_cmp(KEY_PART_INFO *part, uchar *key1, uchar *key2, + uint tuple_length) +{ + uchar *key1_end= key1 + tuple_length; + int UNINIT_VAR(len); + int res; + for (;key1 < key1_end; key1 += len, key2 += len, part++) + { + len= part->store_length; + if (part->null_bit) + { + if (*key1) // key1 == NULL + { + if (!*key2) // key1(NULL) < key2(notNULL) + return -1; + continue; + } + else if (*key2) // key1(notNULL) > key2 (NULL) + return 1; + /* Step over the NULL bytes for key_cmp() call */ + key1++; + key2++; + len--; + } + if ((res= part->field->key_cmp(key1, key2))) + return res; + } + return 0; +} + + +/** + Get hash value for the key from a key buffer + + @param key_info the key descriptor + @param used_key_part number of key parts used for the key + @param key pointer to the buffer with the key value + + @datails + When hashing we should take special care only of: + 1. NULLs (and keyparts which can be null so one byte reserved for it); + 2. Strings for which we have to take into account their collations + and the values of their lengths in the prefixes. + + @return hash value calculated for the key +*/ + +ulong key_hashnr(KEY *key_info, uint used_key_parts, const uchar *key) +{ + ulong nr=1, nr2=4; + KEY_PART_INFO *key_part= key_info->key_part; + KEY_PART_INFO *end_key_part= key_part + used_key_parts; + + for (; key_part < end_key_part; key_part++) + { + uchar *pos= (uchar*)key; + CHARSET_INFO *UNINIT_VAR(cs); + size_t UNINIT_VAR(length), UNINIT_VAR(pack_length); + bool is_string= TRUE; + + key+= key_part->length; + if (key_part->null_bit) + { + key++; /* Skip null byte */ + if (*pos) /* Found null */ + { + nr^= (nr << 1) | 1; + /* Add key pack length to key for VARCHAR segments */ + switch (key_part->type) { + case HA_KEYTYPE_VARTEXT1: + case HA_KEYTYPE_VARBINARY1: + case HA_KEYTYPE_VARTEXT2: + case HA_KEYTYPE_VARBINARY2: + key+= 2; + break; + default: + ; + } + continue; + } + pos++; /* Skip null byte */ + } + /* If it is string set parameters of the string */ + switch (key_part->type) { + case HA_KEYTYPE_TEXT: + cs= key_part->field->charset(); + length= key_part->length; + pack_length= 0; + break; + case HA_KEYTYPE_BINARY : + cs= &my_charset_bin; + length= key_part->length; + pack_length= 0; + break; + case HA_KEYTYPE_VARTEXT1: + case HA_KEYTYPE_VARTEXT2: + cs= key_part->field->charset(); + length= uint2korr(pos); + pack_length= 2; + break; + case HA_KEYTYPE_VARBINARY1: + case HA_KEYTYPE_VARBINARY2: + cs= &my_charset_bin; + length= uint2korr(pos); + pack_length= 2; + break; + default: + is_string= FALSE; + } + + if (is_string) + { + if (cs->mbmaxlen > 1) + { + size_t char_length= cs->charpos(pos + pack_length, + pos + pack_length + length, + length / cs->mbmaxlen); + set_if_smaller(length, char_length); + } + cs->hash_sort(pos+pack_length, length, &nr, &nr2); + key+= pack_length; + } + else + { + for (; pos < (uchar*)key ; pos++) + { + nr^=(ulong) ((((uint) nr & 63)+nr2)*((uint) *pos)) + (nr << 8); + nr2+=3; + } + } + } + DBUG_PRINT("exit", ("hash: %lx", nr)); + return(nr); +} + + +/** + Check whether two keys in the key buffers are equal + + @param key_info the key descriptor + @param used_key_part number of key parts used for the keys + @param key1 pointer to the buffer with the first key + @param key2 pointer to the buffer with the second key + + @detail See details of key_hashnr(). + + @retval TRUE keys in the buffers are NOT equal + @retval FALSE keys in the buffers are equal +*/ + +bool key_buf_cmp(KEY *key_info, uint used_key_parts, + const uchar *key1, const uchar *key2) +{ + KEY_PART_INFO *key_part= key_info->key_part; + KEY_PART_INFO *end_key_part= key_part + used_key_parts; + + for (; key_part < end_key_part; key_part++) + { + uchar *pos1= (uchar*)key1; + uchar *pos2= (uchar*)key2; + CHARSET_INFO *UNINIT_VAR(cs); + size_t UNINIT_VAR(length1), UNINIT_VAR(length2), UNINIT_VAR(pack_length); + bool is_string= TRUE; + + key1+= key_part->length; + key2+= key_part->length; + if (key_part->null_bit) + { + key1++; key2++; /* Skip null byte */ + if (*pos1 && *pos2) /* Both are null */ + { + /* Add key pack length to key for VARCHAR segments */ + switch (key_part->type) { + case HA_KEYTYPE_VARTEXT1: + case HA_KEYTYPE_VARBINARY1: + case HA_KEYTYPE_VARTEXT2: + case HA_KEYTYPE_VARBINARY2: + key1+= 2; key2+= 2; + break; + default: + ; + } + continue; + } + if (*pos1 != *pos2) + return TRUE; + pos1++; pos2++; + } + + /* If it is string set parameters of the string */ + switch (key_part->type) { + case HA_KEYTYPE_TEXT: + cs= key_part->field->charset(); + length1= length2= key_part->length; + pack_length= 0; + break; + case HA_KEYTYPE_BINARY : + cs= &my_charset_bin; + length1= length2= key_part->length; + pack_length= 0; + break; + case HA_KEYTYPE_VARTEXT1: + case HA_KEYTYPE_VARTEXT2: + cs= key_part->field->charset(); + length1= uint2korr(pos1); + length2= uint2korr(pos2); + pack_length= 2; + break; + case HA_KEYTYPE_VARBINARY1: + case HA_KEYTYPE_VARBINARY2: + cs= &my_charset_bin; + length1= uint2korr(pos1); + length2= uint2korr(pos2); + pack_length= 2; + break; + default: + is_string= FALSE; + } + + if (is_string) + { + /* + Compare the strings taking into account length in characters + and collation + */ + size_t byte_len1= length1, byte_len2= length2; + if (cs->mbmaxlen > 1) + { + size_t char_length1= cs->charpos(pos1 + pack_length, + pos1 + pack_length + length1, + length1 / cs->mbmaxlen); + size_t char_length2= cs->charpos(pos2 + pack_length, + pos2 + pack_length + length2, + length2 / cs->mbmaxlen); + set_if_smaller(length1, char_length1); + set_if_smaller(length2, char_length2); + } + if (length1 != length2 || + cs->strnncollsp(pos1 + pack_length, byte_len1, + pos2 + pack_length, byte_len2)) + return TRUE; + key1+= pack_length; key2+= pack_length; + } + else + { + /* it is OK to compare non-string byte per byte */ + for (; pos1 < (uchar*)key1 ; pos1++, pos2++) + { + if (pos1[0] != pos2[0]) + return TRUE; + } + } + } + return FALSE; +} |