This patch ensures that all identical character sets shares the same
cs->csname.
This allows us to replace strcmp() in my_charset_same() with comparisons
of pointers. This fixes a long standing performance issue that could cause
as strcmp() for every item sent trough the protocol class to the end user.
One consequence of this patch is that we don't allow one to add a character
definition in the Index.xml file that changes the csname of an existing
character set. This is by design as changing character set names of existing
ones is extremely dangerous, especially as some storage engines just records
character set numbers.
As we now have a hash over character set's csname, we can in the future
use that for faster access to a specific character set. This could be done
by changing the hash to non unique and use the hash to find the next
character set with same csname.
The code did not take into account that:
- U+005C (backslash) can occupy more than mbminlen characters (e.g. in sjis)
- Some character sets do not have a code for U+005C (e.g. swe7)
Adding a new function my_wc_to_printable into MY_CHARSET_HANDLER to
cover all special cases easier.
After the MDEV-13118 fix there's no code in the server that
wants caseup/casedn to change the argument in place for simple
charsets. Let's remove this logic and always return the result in a
new string for all charsets, both simple and complex.
1. Removing the optimization that *some* character sets used in casedn()
and caseup(), which allowed (and required) to change the case in-place,
overwriting the string passed as the "src" argument.
Now all CHARSET_INFO's work in the same way:
non of them change the source string in-place, all of them now convert
case from the source string to the destination string, leaving
the source string untouched.
2. Adding "const" qualifier to the "char *src" parameter
to caseup() and casedn().
3. Removing duplicate implementations in ctype-mb.c.
Now both caseup() and casedn() implementations for all CJK character sets
use internally the same function my_casefold_mb()
(the former my_casefold_mb_varlen()).
4. Removing the "unused" attribute from parameters of some my_case{up|dn}_xxx()
implementations, as the affected parameters are now *used* in the code.
Previously these parameters were used only in DBUG_ASSERT().
If compiling a non DBUG binary with
-DDBUG_ASSERT_AS_PRINTF asserts will be
changed to printf + stack trace (of stack
trace are enabled).
- Changed #ifndef DBUG_OFF to
#ifdef DBUG_ASSERT_EXISTS
for those DBUG_OFF that was just used to enable
assert
- Assert checking that could greatly impact
performance where changed to DBUG_ASSERT_SLOW which
is not affected by DBUG_ASSERT_AS_PRINTF
- Added one extra option to my_print_stacktrace() to
get more silent in case of stack trace printing as
part of assert.
This is a pre-requisite patch for:
- MDEV-8433 Make field<'broken-string' use indexes
- MDEV-8625 Bad result set with ignorable characters when using a prefix key
- MDEV-8626 Bad result set with contractions when using a prefix key
Adding a new virtual function MY_CHARSET_HANDLER::copy_abort().
Moving character set specific code into the correspoding implementations
(for simple, multi-byte and mbmaxlen>1 character sets).
The problem was that my_hash_sort didn't properly delete end-space characters properly, so strings that should compare
identically was seen as different strings. (Space was handled correctly, but not NBSP)
This caused duplicate key errors when a heap table was converted to Aria as part of overflow in group by.
Fixed by removing all characters that compares as end space when creating a hash.
Other things:
- Fixed that --sorted_results also works for errors in mysqltest.
- Speed up hash by not comparing strings that has different hash.
- Speed up many my_hash_sort functions by using registers to calculate hash instead of pointers.
This was previously done for some functions, but not for all.
- Made a macro of the hash function, to simplify code and to be able to experiment with new hash functions.
client/mysqltest.cc:
Fixed that --sorted_results also works for error messages.
mysql-test/r/ctype_partitions.result:
New test to ensure that partitions on hash works
mysql-test/suite/multi_source/gtid.result:
Updated result
mysql-test/suite/multi_source/gtid.test:
Test that --sorted_result works for error messages
mysql-test/suite/multi_source/gtid_ignore_duplicates.result:
Updated result
mysql-test/suite/multi_source/gtid_ignore_duplicates.test:
Updated result
mysql-test/suite/multi_source/load_data.result:
Updated result
mysql-test/suite/multi_source/load_data.test:
Updated result
mysql-test/t/ctype_partitions.test:
New test to ensure that partitions on hash works
storage/heap/hp_write.c:
Speed up hash by not comparing strings that has different hash.
storage/maria/ma_check.c:
Extra debug
strings/ctype-bin.c:
Use macro for hash function
strings/ctype-latin1.c:
Use macro for hash function
Use registers to calculate hash (speedup)
strings/ctype-mb.c:
Use macro for hash function
Use registers to calculate hash (speedup)
strings/ctype-simple.c:
Use macro for hash function
Use same variable names as in other my_hash_sort functions.
Update my_hash_sort_simple() to properly remove end space (patch by Bar)
strings/ctype-uca.c:
Ignore duplicated space inside strings and end space in my_hash_sort_uca(). This fixed MDEV-6255
Use macro for hash function
Use registers to calculate hash (speedup)
strings/ctype-ucs2.c:
Use macro for hash function
Use registers to calculate hash (speedup)
strings/ctype-utf8.c:
Use macro for hash function
Use registers to calculate hash (speedup)
strings/strings_def.h:
Made a macro of the hash function, to simplify code and to be able to experiment with new hash functions.
