Subquery executes twice, at top level JOIN::optimize and ::execute stages.
At first execution create_sort_index() function is called and
FT_SELECT object is created and destroyed. HANDLER::ft_handler is cleaned up
in the object destructor and at second execution FT_SELECT::get_next() method
returns error.
The fix is to reinit HANDLER::ft_handler field before re-execution of subquery.
Conflicts:
Text conflict in mysql-test/r/func_str.result
Text conflict in mysql-test/suite/sys_vars/r/myisam_sort_buffer_size_basic_32.result
Text conflict in mysql-test/suite/sys_vars/r/myisam_sort_buffer_size_basic_64.result
Text conflict in mysql-test/t/func_str.test
Text conflict in sql/mysqld.cc
Text conflict in sql/protocol.cc
Text conflict in storage/myisam/mi_open.c
Repairing MyISAM table with fulltext indexes and low
myisam_sort_buffer_size may crash the server.
Estimation of number of index entries was done incorrectly,
causing further assertion failure or server crash.
Docs note: min value for myisam_sort_buffer_size has been
changed from 4 to 4096.
Performing fulltext prefix search (a word with truncation
operator) may cause a dead-loop. ft_min_word_len value
doesn't matter actually.
The problem was introduced along with "smarter index merge"
optimization.
fulltext search and row op.
The search for fulltext indexes is searching for some special
predicate layouts. While doing so it's not checking for the number
of columns of the expressions it tries to calculate.
And since row expressions can't return a single scalar value there
was a crash.
Fixed by checking if the expressions are scalar (in addition to
being constant) before calling Item::val_xxx() methods.
SPATIAL and FULLTEXT indexes don't support algorithm
selection.
Disabled by creating a special grammar rule for these
in the parser.
Added some encasulation of duplicate parser code.
inside subquery
Re-setting a fulltext index was a no-operation if not all
the matches of a search were consumed by reading them.
This was preventing a joined table using a fulltext index
in a subquery that requires only 1 row of output (e.g. EXISTS)
from working correctly because the second execution of the
sub-query has the fulltext index cursor in a wrong state and
was not finding results.
Fixed by making the re-init code _ftb_init_index_search()
to re-set open cursors in addition to depleted ones.
match against.
Server crashes when executing prepared statement with duplicating
MATCH() function calls in SELECT and ORDER BY expressions, e.g.:
SELECT MATCH(a) AGAINST('test') FROM t1 ORDER BY MATCH(a) AGAINST('test')
This query gets optimized by the server, so the value returned
by MATCH() from the SELECT list is reused for ORDER BY purposes.
To make this optimization server is comparing items from
SELECT and ORDER BY lists. We were getting server crash because
comparision function for MATCH() item is not intended to be called
at this point of execution.
In 5.0 and 5.1 this problem is workarounded by resetting MATCH()
item to the state as it was during PREPARE.
In 6.0 correct comparision function will be implemented and
duplicating MATCH() items from the ORDER BY list will be
optimized.
single quote fails in 5.1.x
Performing fulltext prefix search (a word with truncation
operator) may cause a dead-loop.
The problem was in smarter index merge algorithm - it was writing
record reference to an incorrect memory area.
MATCH() function accepts column list as an argument. It was possible to override
this requirement with aliased non-column select expression. Which results in
server crash.
With this fix aliased non-column select expressions are not accepted by MATCH()
function, returning an error.
With fix for bug 25951 index hints are ignored for fulltext
searches, as handling of fulltext indexes is different from
handling regular indexes. Meaning it is not possible to
implement true index hints support for fulltext indexes within
the scope of current fulltext architecture.
The problem is that prior to fix for bug 25951, some useful
index hints still could be given for boolean mode searches.
This patch implements special index hints support for fulltext
indexes with the following characteristics:
- all index hints are still ignored for NLQ mode searches -
it cannot work without an index;
- for 5.1 and up index hints FOR ORDER BY and FOR GROUP BY are
still ignored for fulltext indexes;
- boolean mode searches honor USE/FORCE/IGNORE INDEX hints;
- as opposed to index hints for regular indexes, index hints
for fulltext BOOLEAN mode searches affect the usage of the
index for the whole query.
Fulltext boolean mode phrase search may crash server on platforms
where size of pointer is not equal to size of unsigned integer
(in other words some 64-bit platforms).
The problem was integer overflow.
Affects 4.1 only.
Part 2:
Searching fulltext index for a word with boolean mode truncation
operator may cause infinite loop.
The problem was that "smarter index merge" was used with "trunc-words",
which must never happen.
Affects 5.1 only.
Part 1:
Do not perform index search for a plus-word with truncation operator
in case there are other plus-words in expression.
Specifically this optimization was enforced for expression like
"+word1 +word2*", but wasn't enforced for expression like
"+word1 word2*".
hangs 100% cpu
Fulltext parser may fall into infinite loop when it gets illegal
multibyte sequence (or a sequence that doesn't have mapping to unicode).
Affects 5.1 only.
IGNORE/USE/FORCE INDEX hints were honored when choosing FULLTEXT
index.
With this fix these hints are ignored. For regular indexes we may
perform table scan instead of index lookup when IGNORE INDEX was
specified. We cannot do this for FULLTEXT in NLQ mode.
"Process NATURAL and USING joins according to SQL:2003".
* Some of the main problems fixed by the patch:
- in "select *" queries the * expanded correctly according to
ANSI for arbitrary natural/using joins
- natural/using joins are correctly transformed into JOIN ... ON
for any number/nesting of the joins.
- column references are correctly resolved against natural joins
of any nesting and combined with arbitrary other joins.
* This patch also contains a fix for name resolution of items
inside the ON condition of JOIN ... ON - in this case items must
be resolved only against the JOIN operands. To support such
'local' name resolution, the patch introduces a stack of
name resolution contexts used at parse time.
NOTICE:
- This patch is not complete in the sense that
- there are 2 test cases that still do not pass -
one in join.test, one in select.test. Both are marked
with a comment "TODO: WL#2486".
- it does not include a new test specific for the task
