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Fixes bug when we run bcmp() on row when the storage engine hasn't filled in all fields in the row.

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This was triggered by innodb.innodb_multi_update, where we had a static length row without nulls and xtradb didn't fill in the delete-marker byte


include/my_bitmap.h:
  Added prototype for bitmap_union_is_set_all()
mysys/my_bitmap.c:
  Added function to check if union of two bit maps covers all bits.
sql/mysql_priv.h:
  Updated protype for compare_record()
sql/sql_insert.cc:
  Send to compare_record() flag if all fields are used.
sql/sql_select.cc:
  Set share->null_bytes_for_compare.
sql/sql_update.cc:
  In compare_record() don't use the fast cmp_record() (which is basically memcmp) if we don't know that all fields exists.
  Don't compare the null_bytes if there is no data there.
sql/table.cc:
  Store in share->null_bytes_for_compare the number of bytes that has null or bit fields (but not delete marker)
  Store in can_cmp_whole_record if we can use memcmp() (assuming all rows are read) to compare rows in compare_record()
sql/table.h:
  Added two elements in table->share to speed up checking how updated rows can be compared.
This commit is contained in:
Michael Widenius 2010-08-04 16:01:13 +03:00
parent 34e0c8f4c5
commit cd9706b27e
8 changed files with 64 additions and 16 deletions
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2
include/my_bitmap.h
View File

@ -53,6 +53,8 @@ extern my_bool bitmap_is_overlapping(const MY_BITMAP *map1,
extern my_bool bitmap_test_and_set(MY_BITMAP *map, uint bitmap_bit);
extern my_bool bitmap_test_and_clear(MY_BITMAP *map, uint bitmap_bit);
extern my_bool bitmap_fast_test_and_set(MY_BITMAP *map, uint bitmap_bit);
extern my_bool bitmap_union_is_set_all(const MY_BITMAP *map1,
const MY_BITMAP *map2);
extern uint bitmap_set_next(MY_BITMAP *map);
extern uint bitmap_get_first(const MY_BITMAP *map);
extern uint bitmap_get_first_set(const MY_BITMAP *map);

18
mysys/my_bitmap.c
View File

@ -378,6 +378,24 @@ void bitmap_intersect(MY_BITMAP *map, const MY_BITMAP *map2)
}
}
/* True if union of bitmaps have all bits set */
my_bool bitmap_union_is_set_all(const MY_BITMAP *map1, const MY_BITMAP *map2)
{
my_bitmap_map *m1= map1->bitmap, *m2= map2->bitmap, *end;
DBUG_ASSERT(map1->bitmap && map2->bitmap &&
map1->n_bits==map2->n_bits);
*map1->last_word_ptr|= map1->last_word_mask;
end= map1->last_word_ptr;
while ( m1 <= end)
if ((*m1++ | *m2++) != 0xFFFFFFFF)
return FALSE;
return TRUE;
}
/*
Set/clear all bits above a bit.

2
sql/mysql_priv.h
View File

@ -1064,7 +1064,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
char* packet, uint packet_length);
void log_slow_statement(THD *thd);
bool check_dup(const char *db, const char *name, TABLE_LIST *tables);
bool compare_record(TABLE *table);
bool compare_record(TABLE *table, bool all_columns_exists);
bool append_file_to_dir(THD *thd, const char **filename_ptr,
const char *table_name);
void wait_while_table_is_used(THD *thd, TABLE *table,

5
sql/sql_insert.cc
View File

@ -1509,9 +1509,10 @@ int write_record(THD *thd, TABLE *table,COPY_INFO *info)
table->file->adjust_next_insert_id_after_explicit_value(
table->next_number_field->val_int());
info->touched++;
if ((table->file->ha_table_flags() & HA_PARTIAL_COLUMN_READ &&
if (((table->file->ha_table_flags() & HA_PARTIAL_COLUMN_READ) &&
!bitmap_is_subset(table->write_set, table->read_set)) ||
compare_record(table))
compare_record(table, bitmap_union_is_set_all(table->write_set,
table->read_set)))
{
if ((error=table->file->ha_update_row(table->record[1],
table->record[0])) &&

4
sql/sql_select.cc
View File

@ -10396,7 +10396,7 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
table->null_flags= (uchar*) table->record[0];
share->null_fields= null_count+ hidden_null_count;
share->null_bytes= null_pack_length;
share->null_bytes= share->null_bytes_for_compare= null_pack_length;
}
null_count= (blob_count == 0) ? 1 : 0;
hidden_field_count=param->hidden_field_count;
@ -10762,7 +10762,7 @@ TABLE *create_virtual_tmp_table(THD *thd, List<Create_field> &field_list)
{
table->null_flags= (uchar*) table->record[0];
share->null_fields= null_count;
share->null_bytes= null_pack_length;
share->null_bytes= share->null_bytes_for_compare= null_pack_length;
}
table->in_use= thd; /* field->reset() may access table->in_use */

33
sql/sql_update.cc
View File

@ -27,14 +27,14 @@
/* Return 0 if row hasn't changed */
bool compare_record(TABLE *table)
bool compare_record(TABLE *table, bool all_columns_exists)
{
if (table->s->blob_fields + table->s->varchar_fields == 0)
if (table->s->can_cmp_whole_record && all_columns_exists)
return cmp_record(table,record[1]);
/* Compare null bits */
if (memcmp(table->null_flags,
table->null_flags+table->s->rec_buff_length,
table->s->null_bytes))
table->s->null_bytes_for_compare))
return TRUE; // Diff in NULL value
/* Compare updated fields */
for (Field **ptr= table->field ; *ptr ; ptr++)
@ -186,7 +186,7 @@ int mysql_update(THD *thd,
bool using_limit= limit != HA_POS_ERROR;
bool safe_update= test(thd->options & OPTION_SAFE_UPDATES);
bool used_key_is_modified, transactional_table, will_batch;
bool can_compare_record;
bool can_compare_record, all_columns_exists;
int res;
int error, loc_error;
uint used_index= MAX_KEY, dup_key_found;
@ -574,6 +574,9 @@ int mysql_update(THD *thd,
can_compare_record= (!(table->file->ha_table_flags() &
HA_PARTIAL_COLUMN_READ) ||
bitmap_is_subset(table->write_set, table->read_set));
all_columns_exists= (can_compare_record &&
bitmap_union_is_set_all(table->write_set,
table->read_set));
while (!(error=info.read_record(&info)) && !thd->killed)
{
@ -591,7 +594,7 @@ int mysql_update(THD *thd,
found++;
if (!can_compare_record || compare_record(table))
if (!can_compare_record || compare_record(table, all_columns_exists))
{
if ((res= table_list->view_check_option(thd, ignore)) !=
VIEW_CHECK_OK)
@ -1758,11 +1761,14 @@ bool multi_update::send_data(List<Item> &not_used_values)
*/
if (table == table_to_update)
{
bool can_compare_record;
bool can_compare_record, all_columns_exists;
can_compare_record= (!(table->file->ha_table_flags() &
HA_PARTIAL_COLUMN_READ) ||
bitmap_is_subset(table->write_set,
table->read_set));
all_columns_exists= (can_compare_record &&
bitmap_union_is_set_all(table->write_set,
table->read_set));
table->status|= STATUS_UPDATED;
store_record(table,record[1]);
if (fill_record_n_invoke_before_triggers(thd, *fields_for_table[offset],
@ -1777,7 +1783,7 @@ bool multi_update::send_data(List<Item> &not_used_values)
*/
table->auto_increment_field_not_null= FALSE;
found++;
if (!can_compare_record || compare_record(table))
if (!can_compare_record || compare_record(table, all_columns_exists))
{
int error;
if ((error= cur_table->view_check_option(thd, ignore)) !=
@ -1964,7 +1970,7 @@ int multi_update::do_updates()
DBUG_RETURN(0);
for (cur_table= update_tables; cur_table; cur_table= cur_table->next_local)
{
bool can_compare_record;
bool can_compare_record, all_columns_exists;
uint offset= cur_table->shared;
table = cur_table->table;
@ -1988,9 +1994,11 @@ int multi_update::do_updates()
Setup copy functions to copy fields from temporary table
*/
List_iterator_fast<Item> field_it(*fields_for_table[offset]);
Field **field= tmp_table->field +
1 + unupdated_check_opt_tables.elements; // Skip row pointers
Field **field;
Copy_field *copy_field_ptr= copy_field, *copy_field_end;
/* Skip row pointers */
field= tmp_table->field + 1 + unupdated_check_opt_tables.elements;
for ( ; *field ; field++)
{
Item_field *item= (Item_field* ) field_it++;
@ -2005,6 +2013,9 @@ int multi_update::do_updates()
HA_PARTIAL_COLUMN_READ) ||
bitmap_is_subset(table->write_set,
table->read_set));
all_columns_exists= (can_compare_record &&
bitmap_union_is_set_all(table->write_set,
table->read_set));
for (;;)
{
@ -2046,7 +2057,7 @@ int multi_update::do_updates()
TRG_ACTION_BEFORE, TRUE))
goto err2;
if (!can_compare_record || compare_record(table))
if (!can_compare_record || compare_record(table, all_columns_exists))
{
int error;
if ((error= cur_table->view_check_option(thd, ignore)) !=

10
sql/table.cc
View File

@ -687,6 +687,7 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
const char **interval_array;
enum legacy_db_type legacy_db_type;
my_bitmap_map *bitmaps;
bool null_bits_are_used;
DBUG_ENTER("open_binary_frm");
new_field_pack_flag= head[27];
@ -1134,6 +1135,7 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
goto err;
record= share->default_values-1; /* Fieldstart = 1 */
null_bits_are_used= share->null_fields != 0;
if (share->null_field_first)
{
null_flags= null_pos= (uchar*) record+1;
@ -1306,6 +1308,7 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
reg_field->comment=comment;
if (field_type == MYSQL_TYPE_BIT && !f_bit_as_char(pack_flag))
{
null_bits_are_used= 1;
if ((null_bit_pos+= field_length & 7) > 7)
{
null_pos++;
@ -1594,6 +1597,13 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
share->null_bytes= (null_pos - (uchar*) null_flags +
(null_bit_pos + 7) / 8);
share->last_null_bit_pos= null_bit_pos;
share->null_bytes_for_compare= null_bits_are_used ? share->null_bytes : 0;
share->can_cmp_whole_record= (share->blob_fields == 0 &&
share->varchar_fields == 0 &&
(share->null_bytes_for_compare ==
share->null_bytes ||
!(handler_file->ha_table_flags() &
HA_PARTIAL_COLUMN_READ)));
share->db_low_byte_first= handler_file->low_byte_first();
share->column_bitmap_size= bitmap_buffer_size(share->fields);

6
sql/table.h
View File

@ -401,6 +401,11 @@ typedef struct st_table_share
uint blob_ptr_size; /* 4 or 8 */
uint key_block_size; /* create key_block_size, if used */
uint null_bytes, last_null_bit_pos;
/*
Same as null_bytes, except that if there is only a 'delete-marker' in
the record then this value is 0.
*/
uint null_bytes_for_compare;
uint fields; /* Number of fields */
uint rec_buff_length; /* Size of table->record[] buffer */
uint keys, key_parts;
@ -432,6 +437,7 @@ typedef struct st_table_share
bool name_lock, replace_with_name_lock;
bool waiting_on_cond; /* Protection against free */
bool deleting; /* going to delete this table */
bool can_cmp_whole_record;
ulong table_map_id; /* for row-based replication */
/*