In the method Item_field::fix_fields we try to resolve the name of
the field against the names of the aliases that occur in the select
list. This is done by a call of the function find_item_in_list.
When this function finds several occurrences of the field name
it sends an error message to the error queue and returns 0.
Yet the code did not take into account that find_item_in_list
could return 0 and tried to dereference the returned value.
server
The problem was that when memory was exhausted HEAP engine could crash
(GROUP BY uses HEAP TABLE). Alternatively, if SET was used, it could
report an error "You may only use constant expressions with SET" instead
of "Out of memory (Needed NNNNNN bytes)".
The solution is:
- pass MY_WME to (some) calls to my_malloc() to get correct message.
- fix heap_write() so that the first key is skipped during cleanup
on ENOMEM because it wasn't inserted and doesn't have to be
deleted.
No test case is provided because we can't test out-of-memory behaviour
in our current test framework.
Bug#4968 "Stored procedure crash if cursor opened on altered table"
Bug#19733 "Repeated alter, or repeated create/drop, fails"
Bug#19182 "CREATE TABLE bar (m INT) SELECT n FROM foo; doesn't work from
stored procedure."
Bug#6895 "Prepared Statements: ALTER TABLE DROP COLUMN does nothing"
Bug#22060 "ALTER TABLE x AUTO_INCREMENT=y in SP crashes server"
Test cases for bugs 4968, 19733, 6895 will be added in 5.0.
Re-execution of CREATE DATABASE, CREATE TABLE and ALTER TABLE
statements in stored routines or as prepared statements caused
incorrect results (and crashes in versions prior to 5.0.25).
In 5.1 the problem occured only for CREATE DATABASE, CREATE TABLE
SELECT and CREATE TABLE with INDEX/DATA DIRECTOY options).
The problem of bugs 4968, 19733, 19282 and 6895 was that functions
mysql_prepare_table, mysql_create_table and mysql_alter_table were not
re-execution friendly: during their operation they used to modify contents
of LEX (members create_info, alter_info, key_list, create_list),
thus making the LEX unusable for the next execution.
In particular, these functions removed processed columns and keys from
create_list, key_list and drop_list. Search the code in sql_table.cc
for drop_it.remove() and similar patterns to find evidence.
The fix is to supply to these functions a usable copy of each of the
above structures at every re-execution of an SQL statement.
To simplify memory management, LEX::key_list and LEX::create_list
were added to LEX::alter_info, a fresh copy of which is created for
every execution.
The problem of crashing bug 22060 stemmed from the fact that the above
metnioned functions were not only modifying HA_CREATE_INFO structure in
LEX, but also were changing it to point to areas in volatile memory of
the execution memory root.
The patch solves this problem by creating and using an on-stack
copy of HA_CREATE_INFO (note that code in 5.1 already creates and
uses a copy of this structure in mysql_create_table()/alter_table(),
but this approach didn't work well for CREATE TABLE SELECT statement).
- Using DATA/INDEX DIRECTORY option on Windows put data/index file into
default directory because the OS doesn't support readlink().
- The procedure for changing data/index file directory is
different under Windows.
- With this fix we report a warning if DATA/INDEX option is used,
but OS doesn't support readlink().
table
ROW_FORMAT option is lost during CREATE/DROP INDEX.
This fix forces CREATE/DROP INDEX to retain ROW_FORMAT by instructing
mysql_alter_table() that ROW_FORMAT is not used during creating/dropping
indexes.
The problem is that the GEOMETRY NOT NULL can't automatically set
any value as a default one. We always tried to complete LOAD DATA
command even if there's not enough data in file. That doesn't work
for GEOMETRY NOT NULL. Now Field_*::reset() returns an error sign
and it's checked in mysql_load()
Problem: replication of LC_TIME_NAMES didn't work.
Thus, INSERTS or UPDATES using date_format() always
worked with en_US on the slave side.
Fix: adding ONE_SHOT implementation for LC_TIME_NAMES.
This error is displayed anytime the SELECT statement needs a temp table to
return correct results because the object (select_dumpvar) that represents
variables named in the INTO clause stored the results before the temp
table was considered. The problem was fixed by creating the necessary
Item_func_set_user_var objects once the correct data is ready.
