When marking used columns the function find_field_in_table_ref() erroneously
called the walk method for the real item behind a view/derived table field
with the second parameter set to TRUE.
This erroneous code was introduced in 2006.
Bug#17867117 - ERROR RESULT WHEN "COUNT + DISTINCT + CASE WHEN" NEED MERGE_WALK
Problem:
COUNT DISTINCT gives incorrect result when it uses a Unique
Tree and its last inserted record has null value.
Here is how COUNT DISTINCT is processed, given that this query is not
using loose index scan.
When a row is produced as a result of joining tables (there is only
one table here), we store the SELECTed value in a Unique tree. This
allows elimination of any duplicates, and thus implements DISTINCT.
When we have processed all rows like this, we walk the Unique tree,
counting its elements, in Aggregator_distinct::endup() (tree->walk());
for each element we call Item_sum_count::add(). Such function wants to
ignore any NULL value, for that it checks item_sum -> args[0] ->
null_value. It is a mistake: when walking the Unique tree, the value
to be aggregated is not item_sum ->args[0] but rather table ->
field[0].
Solution:
instead of item_sum -> args[0] -> null_value, use arg_is_null(), which
knows where to look (like in fix for bug 57932).
As a consequence of this solution, we have to make arg_is_null() a
little more general:
1) Because it was so far only used for AVG() (which always has a
single argument), this function was looking at a single argument; now
that it has to work with COUNT(DISTINCT expression1,expression2), it
must look at all arguments.
2) Because we start using arg_is_null () for COUNT(DISTINCT), i.e. in
Item_sum_count::add (), it implies that we are also using it for
COUNT(no DISTINCT) (same add ()). For COUNT(no DISTINCT), the
nullness to check is that of item_sum -> args[0]. But the null_value
of such item is reliable only if val_*() has been called on it. So far
arg_is_null() was always used after a call to arg_val*(), so could
rely on null_value; but for COUNT, there is no call to arg_val*(), so
arg_is_null() has to call is_null() instead.
Testcase for 16539979 by Neeraj. Testcase for 17867117 contributed by
Xiaobin Lin from Taobao.
This was actually implemented as part of MDEV-4506, parallel replication.
Unfortunately, one of the conditionals was reversed. So fsync of master.info
was disabled in non-gtid mode, instead of in gtid mode.
So fix the conditional to be correct.
fix the code to compile with clang. fix warnings too.
include/probes_mysql_nodtrace.h:
clang++ doesn't like numeric _constants_ being used in ||
(it suspects that the intention was | ). Boolean constants are ok.
sql/hostname.cc:
only used in DBUG_ASSERT
sql/item.cc:
str_to_time and str_to_datetime return bool, not MYSQL_TIMESTAMP_xxx
sql/item_func.cc:
str_to_datetime_with_warn() returns bool, not MYSQL_TIMESTAMP_xxx
storage/cassandra/CMakeLists.txt:
CMAKE_CXX_FLAGS can be empty
storage/connect/odbconn.cpp:
HWND is void*
storage/connect/user_connect.h:
deprecated on FreeBSD and unused anyway
storage/connect/value.cpp:
bad characters inside. unused.
storage/spider/spd_trx.cc:
clang++ warns that memset will also overwrite vtbl. it might be as well a good idea,
as it asserts that the object will only be used as a storage.
silence the warning.
when frm file exists, but the table does not.
In recover_from_failed_open(), allow the discovery
to fail without an error, when
open_strategy == TABLE_LIST::OPEN_IF_EXISTS.
merged from 5.6:
Bug#14521864: MYSQL 5.1 TO 5.5 BUGS PARTITIONING
Bug#16589511: MYSQL_UPGRADE FAILS TO WRITE OUT ENTIRE ALTER TABLE ... ALGORITHM= ... STATEMENT
Bug#16274455: CAN NOT ACESS PARTITIONED TABLES WHEN DOWNGRADED FROM 5.6.11 TO 5.6.10
plus minor changes from 5.6, mainly comments
The update of mysql.gtid_slave_pos during event replication used
the wrong way to disable binary logging for the table updates.
Fix to instead temporarily clear the OPT_BIN_LOG flag.
MALFORMED XPATH EXP
Problem:
A malformed XPATH expression in the ExtractValue query is causing
a server crash. This malformed XPATH expression is resulted when
the position attribute in the substring function contains ".." in
the beginning.
Solution:
The original crash is happening because the "../" is being evaluated
prematurely. It tries to access XML while it hasn't been parsed yet.
The premature evaluation is happening because the val_nodeset function
is being set to constant, in which case we proceed to evaluate them in
JOIN:prepare stage only. The solution to this is setting the val_nodeset
functions as non-constant. This forces us to evaluate the function in
the JOIN:exec stage and thus avoid any premature evaluation of the
XML strings.
WITH MALFORMED XPATH EXP
Problem:
A malformed XPATH expression in the ExtractValue query is
causing a server crash. This malformed XPATH expression is
resulted when the position attribute in the substring function
contains ".." in the beginning.
Solution:
The original crash is happening because the "../" is being
evaluated prematurely. It tries to access XML while it
hasn't been parsed yet. The premature evaluation is happening
because the val_nodeset function is being set to constant,
in which case we proceed to evaluate them in JOIN:prepare
stage only. The solution to this is setting the val_nodeset
functions as non-constant. This forces us to evaluate the function
in the JOIN:exec stage and thus avoid any premature evaluation of
the XML strings.
Attempt to read the master-bin.state file always, even if the
binlog files (master-bin.index and master-bin.XXXXXX) have been
deleted.
This allows to easily preserve the binlog state when provisioning
a new server from a copy of an old one, without needing to copy
over the binlog files themselves.
The earlier pushed fix for the bug was incomplete. It did not remove
the main cause of the problem: the function remove_eq_conds()
removed always true multiple equalities from any conjunct, but did not
adjust the list of them stored in Item_cond_and::cond_equal.current_level.
Simplified the test case for the bug and moved it to another test file.
The fix triggered changes in EXPLAIN EXTENDED for some queries.
MDEV-4725: Incorrect binlog state recovery if crash while writing event group
The binlog state was not recovered correctly if XA is not used (eg. InnoDB
disabled), or if server crashed in the middle of writing an event group to the
binlog.
With this patch, we ensure that recovery of binlog state is done even if we do
not do the full XA binlog recovery, and we ensure that we only recover fully
written event groups into the binlog state.
- Don't pull out a table out of a semi-join if it is on the inner side of an outer join.
- Make join->sort_by_table= get_sort_by_table(...) call after const table detection
is done. That way, the value of join->sort_by_table will match the actual execution.
Which will allow the code in setup_semijoin_dups_elimination() (search for
"Make sure that possible sorting of rows from the head table is not to be employed."
to see that "Using filesort" is going to be used together with Duplicate Elimination (
and change it to Using temporary + Using filesort)
revid:mattias.jonsson@oracle.com-20131119103616-u6t82s8cpgp0q3ex
Use of uninitialized memory in the priority queue used for returning records
in sorted order.
It happens if no previous partition have returned a row since the
beginning of index_init + an index_read* call returned
HA_ERR_KEY_NOT_FOUND for all partitions (otherwise the record
buffer/priority queue would be initialized) + an index_next/prev
call where all partitions returns HA_ERR_END_OF_FILE.
