When values of different types are compared they're converted to a type that
allows correct comparison. This conversion is done for each comparison and
takes some time. When a constant is being compared it's possible to cache the
value after conversion to speedup comparison. In some cases (large dataset,
complex WHERE condition with many type conversions) query might be executed
7% faster.
A test case isn't provided because all changes are internal and isn't visible
outside.
The behavior of the Item_cache is changed to cache values on the first request
of cached value rather than at the moment of storing item to be cached.
A flag named value_cached is added to the Item_cache class. It's set to TRUE
when cache holds the value of the last stored item.
Function named cache_value() is added to the Item_cache class and derived classes.
This function actually caches the value of the saved item.
Item_cache_xxx::store functions now only store item to be cached and set
value_cached flag to FALSE.
Item_cache_xxx::val_xxx functions are changed to call cache_value function
prior to returning cached value if value_cached is FALSE.
The Arg_comparator::set_cmp_func function now calls cache_converted_constant
to cache constants if they need a type conversion.
The Item_cache::get_cache function is overloaded to allow setting of the
cache type.
The cache_converted_constant function is added to the Arg_comparator class.
It checks whether a value can and should be cached and if so caches it.
The problem is that XML functions(items) do not reset null_value
before their execution and further item excution may use
null_value value of the previous result.
The fix is to reset null_value.
Problem:
RelativeLocationPath can appear only after a node-set expression
in the third and the fourth branches of this rule:
PathExpr :: = LocationPath
| FilterExpr
| FilterExpr '/' RelativeLocationPath
| FilterExpr '//' RelativeLocationPath
XPatch code didn't check the type of FilterExpr and crashed.
Fix:
If FilterExpr is a scalar expression
(variable reference, literal, number, scalar function call)
return error.
Faster thr_alarm()
Added 'Opened_files' status variable to track calls to my_open()
Don't give warnings when running mysql_install_db
Added option --source-install to mysql_install_db
I had to do the following renames() as used polymorphism didn't work with Forte compiler on 64 bit systems
index_read() -> index_read_map()
index_read_idx() -> index_read_idx_map()
index_read_last() -> index_read_last_map()
Fixed compiler warnings, errors and link errors
Fixed new bug on Solaris with gethrtime()
Added --debug-check option to all mysql clients to print errors and memory leaks
Added --debug-info to all clients. This now works as --debug-check but also prints memory and cpu usage
--long-query-time is now given in seconds with microseconds as decimals
--min_examined_row_limit added for slow query log
long_query_time user variable is now double with 6 decimals
Added functions to get time in microseconds
Added faster time() functions for system that has gethrtime() (Solaris)
We now do less time() calls.
Added field->in_read_set() and field->in_write_set() for easier field manipulation by handlers
set_var.cc and my_getopt() can now handle DOUBLE variables.
All time() calls changed to my_time()
my_time() now does retry's if time() call fails.
Added debug function for stopping in mysql_admin_table() when tables are locked
Some trivial function and struct variable renames to avoid merge errors.
Fixed compiler warnings
Initialization of some time variables on windows moved to my_init()
Problem: Memory overrun happened in attempts to generate
error messages (e.g. in case of incorrect XPath syntax).
Reason: set_if_bigger() was used instead of set_if_smaller().
Change: replacing wrong set_if_bigger() to set_if_smaller(),
and making minor additional code clean-ups.
The following type conversions was done:
- Changed byte to uchar
- Changed gptr to uchar*
- Change my_string to char *
- Change my_size_t to size_t
- Change size_s to size_t
Removed declaration of byte, gptr, my_string, my_size_t and size_s.
Following function parameter changes was done:
- All string functions in mysys/strings was changed to use size_t
instead of uint for string lengths.
- All read()/write() functions changed to use size_t (including vio).
- All protocoll functions changed to use size_t instead of uint
- Functions that used a pointer to a string length was changed to use size_t*
- Changed malloc(), free() and related functions from using gptr to use void *
as this requires fewer casts in the code and is more in line with how the
standard functions work.
- Added extra length argument to dirname_part() to return the length of the
created string.
- Changed (at least) following functions to take uchar* as argument:
- db_dump()
- my_net_write()
- net_write_command()
- net_store_data()
- DBUG_DUMP()
- decimal2bin() & bin2decimal()
- Changed my_compress() and my_uncompress() to use size_t. Changed one
argument to my_uncompress() from a pointer to a value as we only return
one value (makes function easier to use).
- Changed type of 'pack_data' argument to packfrm() to avoid casts.
- Changed in readfrm() and writefrom(), ha_discover and handler::discover()
the type for argument 'frmdata' to uchar** to avoid casts.
- Changed most Field functions to use uchar* instead of char* (reduced a lot of
casts).
- Changed field->val_xxx(xxx, new_ptr) to take const pointers.
Other changes:
- Removed a lot of not needed casts
- Added a few new cast required by other changes
- Added some cast to my_multi_malloc() arguments for safety (as string lengths
needs to be uint, not size_t).
- Fixed all calls to hash-get-key functions to use size_t*. (Needed to be done
explicitely as this conflict was often hided by casting the function to
hash_get_key).
- Changed some buffers to memory regions to uchar* to avoid casts.
- Changed some string lengths from uint to size_t.
- Changed field->ptr to be uchar* instead of char*. This allowed us to
get rid of a lot of casts.
- Some changes from true -> TRUE, false -> FALSE, unsigned char -> uchar
- Include zlib.h in some files as we needed declaration of crc32()
- Changed MY_FILE_ERROR to be (size_t) -1.
- Changed many variables to hold the result of my_read() / my_write() to be
size_t. This was needed to properly detect errors (which are
returned as (size_t) -1).
- Removed some very old VMS code
- Changed packfrm()/unpackfrm() to not be depending on uint size
(portability fix)
- Removed windows specific code to restore cursor position as this
causes slowdown on windows and we should not mix read() and pread()
calls anyway as this is not thread safe. Updated function comment to
reflect this. Changed function that depended on original behavior of
my_pwrite() to itself restore the cursor position (one such case).
- Added some missing checking of return value of malloc().
- Changed definition of MOD_PAD_CHAR_TO_FULL_LENGTH to avoid 'long' overflow.
- Changed type of table_def::m_size from my_size_t to ulong to reflect that
m_size is the number of elements in the array, not a string/memory
length.
- Moved THD::max_row_length() to table.cc (as it's not depending on THD).
Inlined max_row_length_blob() into this function.
- More function comments
- Fixed some compiler warnings when compiled without partitions.
- Removed setting of LEX_STRING() arguments in declaration (portability fix).
- Some trivial indentation/variable name changes.
- Some trivial code simplifications:
- Replaced some calls to alloc_root + memcpy to use
strmake_root()/strdup_root().
- Changed some calls from memdup() to strmake() (Safety fix)
- Simpler loops in client-simple.c
Problem: when replacing the root element, UpdateXML
erroneously tried to mix old XML content with the
replacement string, which led to crash.
Fix: don't use the old XML content in these cases,
just return the replacement string.
Removed a lot of compiler warnings
Removed not used variables, functions and labels
Initialize some variables that could be used unitialized (fatal bugs)
%ll -> %l
- Removed not used variables
- Changed some ulong parameters/variables to ulonglong (possible serious bug)
- Added casts to get rid of safe assignment from longlong to long (and similar)
- Added casts to function parameters
- Fixed signed/unsigned compares
- Added some constructores to structures
- Removed some not portable constructs
Better fix for bug Bug #21428 "skipped 9 bytes from file: socket (3)" on "mysqladmin shutdown"
(Added new parameter to net_clear() to define when we want the communication buffer to be emptied)
Problem: "greater than" and "less than" XPath operators appeared to have been implemented in reverse.
Fix: swap arguments to eq_func() and eq_func_reverse() to provide correct operation result.
fragment is not well-formed xml
Problem:
- ExtractValue silently returned NULL if a wrong XML value is passed.
- In some cases "unexpected END-OF-INPUT" error was not detected, and
a non-NULL result could be returned for a bad XML value.
Fix:
- Adding warning messages, to make user aware why NULL was returned.
- Missing "unexpected END-OF-INPUT" error is reported now.
Problem source:
Qualified names (aka QName) didn't work as tag names and attribute names,
because the parser lacked a real rule to scan QName, so it understood
only non-qualified names without prefixes.
Solution:
New rule was added to check both "ident" and "ident:ident" sequences.
ExtractValue didn't understand tag and attribute names
consisting of "tricky" national letters (e.g. latin accenter letters).
It happened because XPath lex parser recognized only basic
latin letter a..z ad a part of an identifier.
Fixed to recognize all letters by means of new "full ctype" which
was added recently.
Added missing DBUG_xxx_RETURN statements
Fixed some usage of not initialized variables (as found by valgrind)
Ensure that we don't remove locked tables used as name locks from open table cache until unlock_table_names() are called.
This was fixed by having drop_locked_name() returning any table used as a name lock so that we can free it in unlock_table_names()
This will allow Tomas to continue with his work to use namelocks to syncronize things.
Note: valgrind still produces a lot of warnings about using not initialized code and shows memory loss errors when running the ndb tests
XPath without a XPath syntax error
item_xmlfunc.cc:
Error message didn't happen because after
a failing attempt to parse RelativeLocationPath,
my_xpath_parse_AbsoluteLocationPath() returned success.
Changeing logic a bit:
- Try to parse EOF first, return success if true.
- Then try to parse RelativeLocationPath(), return success if true.
- Otherwise return failure.
xml.result:
Adding test case.
Also, this change made it possible to generate
an error message earlier in the case of another
bad XPATH syntax.
xml.test:
Adding test case.
Adding test.
item_xmlfunc.cc:
Bug #18171 XML: ExtractValue: the XPath position() function crashes the server!
Disallowing use of position() and last() without context.
xml.result, xml.test:
Adding test case.
item_xmlfunc.cc:
- adding "size" member into MY_XPATH_FLT struct,
to pass parent's context size when iterating
in a predicate. Previously, temporaty context
size was calculated instead, which is always 1.
As a result, things like last() and count()
didn't work fine.
- adding iteration into Item_func_xpath_elementbyindex:
similar to Item_func_xpath_predicate.
This is to make things like last() and count()
work inside square brackets.
xml.result, xml.test:
Adding test case.
item_xmlfunc.cc:
Fixed that Item_nodeset_func derived classes
didn't take into account charset of the XML value
and always worked using "binary" charset.
xml.result, xml.test:
Adding test case.
item_xmlfunc.cc:
Adding a special function to handle "self" axis.
Previously "child" and "self" were handled the same.
xml.result, xml.test:
Adding test case.
item_xmlfunc.cc:
Fixed that the "!" character written at the end was ignored.
Now if we try to scan "!=", and if "!" is not
followed by "=", we rollback lex scanner back
to "!" token, so the parser will start to check
the next rule from the "!" character again.
Previously parser started from the next character,
which was EOF in the example in xml.test,
which led to query being successfully parsed,
instead of producing a syntax error.
Also fixes 16314: XML: extractvalue() crash if vertical bar
xml.result, xml.test:
Adding test case
item_xmlfunc.cc:
Using root element as a context node,
instead of NULL, with relative paths.
libmysqld/Makefile.am:
sql/Makefile.am:
Adding new source files.
Adding new file into build process.
include/my_xml.h:
strings/xml.c:
Adding new XML parse flags to skip text normalization and
to use relative tag names. Adding enum for XML token types.
sql/lex.h:
Making parser aware of new SQL functions.
sqll/item_create.h, sql/item_create.cc:
Adding creators for ExtractValue and UpdateXML.
sql/item.h:
Adding new Item types: nodeset and nodeset comparator.
sql/item_xmlfunc.h
sql/item_xmlfunc.cc
Adding new classes implementing XPath functions.
mysql-test/t/xml.test, mysql-test/r/xml.result:
New files: adding test case
