database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00
Code Activity

Fix for bug#22369: Alter table rename combined

Browse Source 
with other alterations causes lost tables

Using RENAME clause combined with other clauses of ALTER TABLE led to
data loss (the data was there but not accessible). This could happen if the
changes do not change the table much. Adding and droppping of fields and
indices was safe. Renaming a column with MODIFY or CHANGE was unsafe operation,
if the actual column didn't change (changing from int to int, which is a noop)
  
Depending on the storage engine (SE) the behavior is different:
1)MyISAM/MEMORY - the ALTER TABLE statement completes
  without any error but next SELECT against the new table fails.
2)InnoDB (and every other transactional table) - The ALTER TABLE statement
  fails. There are the the following files in the db dir -
  `new_table_name.frm` and a temporary table's frm. If the SE is file
  based, then the data and index files will be present but with the old
  names. What happens is that for InnoDB the table is not renamed in the
  internal DDIC.

Fixed by adding additional call to mysql_rename_table() method, which should
not include FRM file rename, because it has been already done during file
names juggling.
This commit is contained in:
andrey@example.com
2006-12-04 18:22:38 +01:00
parent ebee55f48a
commit e6a4727779
7 changed files with 313 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

95
sql/sql_table.cc
View File

@ -3652,10 +3652,12 @@ make_unique_key_name(const char *field_name,KEY *start,KEY *end)
flags flags for build_table_filename().
FN_FROM_IS_TMP old_name is temporary.
FN_TO_IS_TMP new_name is temporary.
NO_FRM_RENAME Don't rename the FRM file
but only the table in the storage engine.
RETURN
0 OK
!= 0 Error
FALSE OK
TRUE Error
*/
bool
@ -3704,7 +3706,7 @@ mysql_rename_table(handlerton *base, const char *old_db,
if (!file || !(error=file->rename_table(from_base, to_base)))
{
if (rename_file_ext(from,to,reg_ext))
if (!(flags & NO_FRM_RENAME) && rename_file_ext(from,to,reg_ext))
{
error=my_errno;
/* Restore old file name */
@ -5197,6 +5199,51 @@ static uint compare_tables(TABLE *table, List<create_field> *create_list,
/*
Alter table
SYNOPSIS
mysql_alter_table()
thd Thread handle
new_db If there is a RENAME clause
new_name If there is a RENAME clause
lex_create_info Information from the parsing phase. Since some
clauses are common to CREATE and ALTER TABLE, the
data is stored in lex->create_info. The non-common
is stored in lex->alter_info.
table_list The table to change.
fields lex->create_list - List of fields to be changed,
added or dropped.
keys lex->key_list - List of keys to be changed, added or
dropped.
order_num How many ORDER BY fields has been specified.
order List of fields to ORDER BY.
ignore Whether we have ALTER IGNORE TABLE
alter_info Information from the parsing phase specific to ALTER
TABLE and not shared with CREATE TABLE.
do_send_ok Whether to call send_ok() on success.
DESCRIPTION
This is a veery long function and is everything but the kitchen sink :)
It is used to alter a table and not only by ALTER TABLE but also
CREATE|DROP INDEX are mapped on this function.
When the ALTER TABLE statement just does a RENAME or ENABLE|DISABLE KEYS,
or both, then this function short cuts its operation by renaming
the table and/or enabling/disabling the keys. In this case, the FRM is
not changed, directly by mysql_alter_table. However, if there is a
RENAME + change of a field, or an index, the short cut is not used.
See how `fields` is used to generate the new FRM regarding the structure
of the fields. The same is done for the indices of the table.
Important is the fact, that this function tries to do as little work as
possible, by finding out whether a intermediate table is needed to copy
data into and when finishing the altering to use it as the original table.
For this reason the function compare_tables() is called, which decides
based on all kind of data how similar are the new and the original
tables.
RETURN VALUES
FALSE OK
TRUE Error
*/
bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
@ -5215,7 +5262,7 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
char reg_path[FN_REFLEN+1];
ha_rows copied,deleted;
uint db_create_options, used_fields;
handlerton *old_db_type, *new_db_type;
handlerton *old_db_type, *new_db_type, *save_old_db_type;
legacy_db_type table_type;
HA_CREATE_INFO *create_info;
frm_type_enum frm_type;
@ -5519,7 +5566,7 @@ view_err:
DBUG_RETURN(error);
}
/* Full alter table */
/* We have to do full alter table */
/* Let new create options override the old ones */
if (!(used_fields & HA_CREATE_USED_MIN_ROWS))
@ -6038,8 +6085,8 @@ view_err:
old data and index files. Create also symlinks to point at
the new tables.
Copy data.
At end, rename temporary tables and symlinks to temporary table
to final table name.
At end, rename intermediate tables, and symlinks to intermediate
table, to final table name.
Remove old table and old symlinks
If rename is made to another database:
@ -6100,6 +6147,7 @@ view_err:
/* table is a normal table: Create temporary table in same directory */
build_table_filename(path, sizeof(path), new_db, tmp_name, "",
FN_IS_TMP);
/* Open our intermediate table */
new_table=open_temporary_table(thd, path, new_db, tmp_name,0);
}
if (!new_table)
@ -6305,7 +6353,7 @@ view_err:
if (new_table)
{
/* close temporary table that will be the new table */
/* Close the intermediate table that will be the new table */
intern_close_table(new_table);
my_free((gptr) new_table,MYF(0));
}
@ -6319,7 +6367,7 @@ view_err:
/*
Data is copied. Now we rename the old table to a temp name,
rename the new one to the old name, remove all entries from the old table
rename the new one to the old name, remove all entries about the old table
from the cache, free all locks, close the old table and remove it.
*/
@ -6346,7 +6394,7 @@ view_err:
{
/*
Win32 and InnoDB can't drop a table that is in use, so we must
close the original table at before doing the rename
close the original table before doing the rename
*/
table->s->version= 0; // Force removal of table def
close_cached_table(thd, table);
@ -6360,6 +6408,21 @@ view_err:
error=0;
save_old_db_type= old_db_type;
/*
This leads to the storage engine (SE) not being notified for renames in
mysql_rename_table(), because we just juggle with the FRM and nothing
more. If we have an intermediate table, then we notify the SE that
it should become the actual table. Later, we will recycle the old table.
However, in case of ALTER TABLE RENAME there might be no intermediate
table. This is when the old and new tables are compatible, according to
compare_table(). Then, we need one additional call to
mysql_rename_table() with flag NO_FRM_RENAME, which does nothing else but
actual rename in the SE and the FRM is not touched. Note that, if the
table is renamed and the SE is also changed, then an intermediate table
is created and the additional call will not take place.
*/
if (!need_copy_table)
new_db_type=old_db_type= NULL; // this type cannot happen in regular ALTER
if (mysql_rename_table(old_db_type, db, table_name, db, old_name,
@ -6369,8 +6432,11 @@ view_err:
VOID(quick_rm_table(new_db_type, new_db, tmp_name, FN_IS_TMP));
}
else if (mysql_rename_table(new_db_type,new_db,tmp_name,new_db,
new_alias, FN_FROM_IS_TMP) ||
new_alias, FN_FROM_IS_TMP) ||
(new_name != table_name || new_db != db) && // we also do rename
(need_copy_table ||
mysql_rename_table(save_old_db_type, db, table_name, new_db,
new_alias, NO_FRM_RENAME)) &&
Table_triggers_list::change_table_name(thd, db, table_name,
new_db, new_alias))
{
@ -6381,6 +6447,7 @@ view_err:
VOID(mysql_rename_table(old_db_type, db, old_name, db, alias,
FN_FROM_IS_TMP));
}
if (error)
{
/*
@ -6412,6 +6479,7 @@ view_err:
goto err;
}
}
if (thd->lock || new_name != table_name || no_table_reopen) // True if WIN32
{
/*
@ -6478,10 +6546,7 @@ view_err:
DBUG_ASSERT(!(mysql_bin_log.is_open() && thd->current_stmt_binlog_row_based &&
(create_info->options & HA_LEX_CREATE_TMP_TABLE)));
write_bin_log(thd, TRUE, thd->query, thd->query_length);
/*
TODO RONM: This problem needs to handled for Berkeley DB partitions
as well
*/
if (ha_check_storage_engine_flag(old_db_type,HTON_FLUSH_AFTER_RENAME))
{
/*