This assertion would occur if UPDATE was used to update multiple
tables containing an AUTO_INCREMENT column and if the inserted
row had a user-supplied value for that column. The assertion
could then be triggered by the next statement.
The problem was only noticeable on debug builds of the server.
The cause of the problem was that the code for multi update did
not properly reset the TABLE->auto_increment_if_null flag after update.
The flag is used to indicate that a non-null value of an auto_increment field
has been provided by the user or retrieved from a current record.
Open_tables() contains an assertion that tests this flag, and this
was triggered in this case by ALTER TABLE.
This patch fixes the problem by resetting the auto_increment_if_null
field to FALSE once a row has been updated.
This bug is similar to Bug#47274, but for multi update rather
than INSERT DELAYED.
Test case added to update.test.
line 138 when forcing a spatial index
Problem: "Spatial indexes can be involved in the search
for queries that use a function such as MBRContains()
or MBRWithin() in the WHERE clause".
Using spatial indexes for JOINs with =, <=> etc.
predicates is incorrect.
Fix: disable spatial indexes for such queries.
grants are reapplied.
After renaming a user and trying to re-apply grants results in additional
grants.
This is because we use username as part of the key for GRANT_TABLE structure.
When the user is renamed, we only change the username stored and the hash key
still contains the old user name and this results in the extra privileges
Fixed by rebuilding the hash key and updating the column_priv_hash structure
when the user is renamed
Problem: the "caseinfo" member of CHARSET_INFO structure was not
initialized for user-defined Unicode collations, which made the
server crash.
Fix: initializing caseinfo properly.
Adding @@session and @@global prefixes to a
declared variable in a stored procedure the server
would lead to a crash.
The reason was that during the parsing of the
syntactic rule 'option_value' an uninitialized
set_var object was pushed to the parameter stack
of the SET statement. The parent rule
'option_type_value' interpreted the existence of
variables on the parameter stack as an assignment
and wrapped it in a sp_instr_set object.
As the procedure later was executed an attempt
was made to run the method 'check()' on an
uninitialized member object (NULL value) belonging
to the previously created but uninitialized object.
Problem: using null microsecond part in a WHERE condition
(e.g. WHERE date_time_field <= "YYYY-MM-DD HH:MM:SS.0000")
may lead to wrong results due to improper DATETIMEs
comparison in some cases.
Fix: comparing DATETIMEs as strings we must trim trailing 0's
in such cases.
The problem was in incorrect handling of predicates involving
NULL as a constant value by the range optimizer.
For example, when creating a SEL_ARG node from a condition of
the form "field < const" (which would normally result in the
"NULL < field < const" SEL_ARG), the special case when "const"
is NULL was not taken into account, so "NULL < field < NULL"
was produced for the "field < NULL" condition.
As a result, SEL_ARG structures of this form could not be
further optimized which in turn could lead to incorrectly
constructed SEL_ARG trees. In particular, code assuming SEL_ARG
structures to always form a sequence of ordered disjoint
intervals could enter an infinite loop under some
circumstances.
Fixed by changing get_mm_leaf() so that for any sargable
predicate except "<=>" involving NULL as a constant, "empty"
SEL_ARG is returned, since such a predicate is always false.
view that has Group By
When SELECT'ing from a view that mentions another,
materialized, view, access was being denied. The issue was
resolved by lifting a special case which avoided such access
checking in check_single_table_access. In the past, this was
necessary since if such a check were performed, the error
message would be downgraded to a warning in the case of SHOW
CREATE VIEW. The downgrading of errors was meant to handle
only that scenario, but could not distinguish the two as it
read only the error messages.
The special case was needed in the fix of bug no 36086.
Before that, views were confused with derived tables.
After bug no 35996 was fixed, the manipulation of errors
during SHOW CREATE VIEW execution is not dependent on the
actual error messages in the queue, it rather looks at the
actual cause of the error and takes appropriate
action. Hence the aforementioned special case is now
superfluous and the bug is fixed.
columns without where/group
Simple SELECT with implicit grouping used to return many rows if
the query was ordered by the aggregated column in the SELECT
list. This was incorrect because queries with implicit grouping
should only return a single record.
The problem was that when JOIN:exec() decided if execution needed
to handle grouping, it was assumed that sum_func_count==0 meant
that there were no aggregate functions in the query. This
assumption was not correct in JOIN::exec() because the aggregate
functions might have been optimized away during JOIN::optimize().
The reason why queries without ordering behaved correctly was
that sum_func_count is only recalculated if the optimizer chooses
to use temporary tables (which it does in the ordered case).
Hence, non-ordered queries were correctly treated as grouped.
The fix for this bug was to remove the assumption that
sum_func_count==0 means that there is no need for grouping. This
was done by introducing variable "bool implicit_grouping" in the
JOIN object.
The problem was in incorrect handling of predicates involving
NULL as a constant value by the range optimizer.
For example, when creating a SEL_ARG node from a condition of
the form "field < const" (which would normally result in the
"NULL < field < const" SEL_ARG), the special case when "const"
is NULL was not taken into account, so "NULL < field < NULL"
was produced for the "field < NULL" condition.
As a result, SEL_ARG structures of this form could not be
further optimized which in turn could lead to incorrectly
constructed SEL_ARG trees. In particular, code assuming SEL_ARG
structures to always form a sequence of ordered disjoint
intervals could enter an infinite loop under some
circumstances.
Fixed by changing get_mm_leaf() so that for any sargable
predicate except "<=>" involving NULL as a constant, "empty"
SEL_ARG is returned, since such a predicate is always false.
Problem: using null microsecond part (e.g. "YYYY-MM-DD HH:MM:SS.0000")
in a WHERE condition may lead to wrong results due to improper
DATETIMEs comparison in some cases.
Fix: as we compare DATETIMEs as strings we must trim trailing 0's
in such cases.
In MySQL when the mapping for space is changed to something other than
0x20 by defining a different collation, then space is not ignored when
comparing two strings.
This was happening because the function that performs the comparison
of two strings while ignoring ending spaces, was comparing the collation
value of a space with the ascii value of the ' ' character. This should
be changed to do comparison between the collated values.
low myisam_sort_buffer_size
Repair by sort (default) or parallel repair of a MyISAM table
(doesn't matter partitioned or not) as well as bulk inserts
and enable indexes some times didn't failover to repair with
key cache.
The problem was that after unsuccessful attempt, data file was
closed. Whereas repair with key cache requires open data file.
Fixed by reopening data file.
Also fixed a valgrind warning, which may appear during repair
by sort or parallel repair with certain myisam_sort_buffer_size
number of rows and length of an index entry (very dependent).
covering index
When two range predicates were combined under an OR
predicate, the algorithm tried to merge overlapping ranges
into one. But the case when a range overlapped several other
ranges was not handled. This lead to
1) ranges overlapping, which gave repeated results and
2) a range that overlapped several other ranges was cut off.
Fixed by
1) Making sure that a range got an upper bound equal to the
next range with a greater minimum.
2) Removing a continue statement
backport for bug#44059 from mysql-pe to mysql-5.1-bugteam
Using the partition with most rows instead of first partition
to estimate the cardinality of indexes.
is reached
Problem was bad error handling, leaving some new temporary
partitions locked and initialized and some not yet initialized
and locked, leading to a crash when trying to unlock the not
yet initialized and locked partitions
Solution was to unlock the already locked partitions, and not
include any of the new temporary partitions in later unlocks
can lead to bad memory access
Problem: Field_bit is the only field which returns INT_RESULT
and doesn't have unsigned flag. As it's not a descendant of the
Field_num, so using ((Field_num *) field_bit)->unsigned_flag may lead
to unpredictable results.
Fix: check the field type before casting.
buffering is used
FORCE INDEX FOR ORDER BY now prevents the optimizer from
using join buffering. As a result the optimizer can use
indexed access on the first table and doesn't need to
sort the complete resultset at the end of the statement.
1. BUG#46000 - using index called GEN_CLUST_INDEX crashes server
Detailed revision comments:
r5895 | jyang | 2009-09-15 03:39:21 +0300 (Tue, 15 Sep 2009) | 5 lines
branches/5.1: Disallow creating index with the name of
"GEN_CLUST_INDEX" which is reserved for the default system
primary index. (Bug #46000) rb://149 approved by Marko Makela.
SELECT ... WHERE ... IN (NULL, ...) does full table scan,
even if the same query without the NULL uses efficient range scan.
The bugfix for the bug 18360 introduced an optimization:
if
1) all right-hand arguments of the IN function are constants
2) result types of all right argument items are compatible
enough to use the same single comparison function to
compare all of them to the left argument,
then
we can convert the right-hand list of constant items to an array
of equally-typed constant values for the further
QUICK index access etc. (see Item_func_in::fix_length_and_dec()).
The Item_null constant item objects have STRING_RESULT
result types, so, as far as Item_func_in::fix_length_and_dec()
is aware of NULLs in the right list, this improvement efficiently
optimizes IN function calls with a mixed right list of NULLs and
string constants. However, the optimization doesn't affect mixed
lists of NULLs and integers, floats etc., because there is no
unique common comparator.
New optimization has been added to ignore the result type
of NULL constants in the static analysis of mixed right-hand lists.
This is safe, because at the execution phase we care about
presence of NULLs anyway.
1. The collect_cmp_types() function has been modified to optionally
ignore NULL constants in the item list.
2. NULL-skipping code of the Item_func_in::fix_length_and_dec()
function has been modified to work not only with in_string
vectors but with in_vectors of other types.
On Mac OS X or Windows, sending a SIGHUP to the server or a
asynchronous flush (triggered by flush_time), would cause the
server to crash.
The problem was that a hook used to detach client API handles
wasn't prepared to handle cases where the thread does not have
a associated session.
The solution is to verify whether the thread has a associated
session before trying to detach a handle.
The 'BEGIN/COMMIT/ROLLBACK' log event could be filtered out if the
database is not selected by --database option of mysqlbinlog command.
This can result in problem if there are some statements in the
transaction are not filtered out.
To fix the problem, mysqlbinlog will output 'BEGIN/ROLLBACK/COMMIT'
in regardless of the database filtering rules.
The 'BEGIN/COMMIT/ROLLBACK' log event could be filtered out if the
database is not selected by --database option of mysqlbinlog command.
This can result in problem if there are some statements in the
transaction are not filtered out.
To fix the problem, mysqlbinlog will output 'BEGIN/ROLLBACK/COMMIT'
in regardless of the database filtering rules.
Backport from 6.0 to 5.1.
Only those sync points are included, which are used in debug_sync.test.
The Debug Sync Facility allows to place synchronization points
in the code:
open_tables(...)
DEBUG_SYNC(thd, "after_open_tables");
lock_tables(...)
When activated, a sync point can
- Send a signal and/or
- Wait for a signal
Nomenclature:
- signal: A value of a global variable that persists
until overwritten by a new signal. The global
variable can also be seen as a "signal post"
or "flag mast". Then the signal is what is
attached to the "signal post" or "flag mast".
- send a signal: Assign the value (the signal) to the global
variable ("set a flag") and broadcast a
global condition to wake those waiting for
a signal.
- wait for a signal: Loop over waiting for the global condition until
the global value matches the wait-for signal.
Please find more information in the top comment in debug_sync.cc
or in the worklog entry.
