Essentially, the problem is that safemalloc is excruciatingly
slow as it checks all allocated blocks for overrun at each
memory management primitive, yielding a almost exponential
slowdown for the memory management functions (malloc, realloc,
free). The overrun check basically consists of verifying some
bytes of a block for certain magic keys, which catches some
simple forms of overrun. Another minor problem is violation
of aliasing rules and that its own internal list of blocks
is prone to corruption.
Another issue with safemalloc is rather the maintenance cost
as the tool has a significant impact on the server code.
Given the magnitude of memory debuggers available nowadays,
especially those that are provided with the platform malloc
implementation, maintenance of a in-house and largely obsolete
memory debugger becomes a burden that is not worth the effort
due to its slowness and lack of support for detecting more
common forms of heap corruption.
Since there are third-party tools that can provide the same
functionality at a lower or comparable performance cost, the
solution is to simply remove safemalloc. Third-party tools
can provide the same functionality at a lower or comparable
performance cost.
The removal of safemalloc also allows a simplification of the
malloc wrappers, removing quite a bit of kludge: redefinition
of my_malloc, my_free and the removal of the unused second
argument of my_free. Since free() always check whether the
supplied pointer is null, redudant checks are also removed.
Also, this patch adds unit testing for my_malloc and moves
my_realloc implementation into the same file as the other
memory allocation primitives.
client/mysqldump.c:
Pass my_free directly as its signature is compatible with the
callback type -- which wasn't the case for free_table_ent.
mysql-test/extra/rpl_tests/rpl_tmp_table_and_DDL.test:
Added missing sync_slave_with_master; Fixes random failures
mysql-test/include/default_mysqld.cnf:
default-character-set -> character-set-server (removes warning in error files for usage of deprecated options)
mysql-test/lib/My/SafeProcess/safe_process.cc:
Fixed compiler warning
mysql-test/lib/v1/mysql-test-run.pl:
default-character-set -> character-set-server (removes warning in error files for usage of deprecated options)
mysql-test/suite/rpl/r/rpl_do_grant.result:
Updated test results
mysql-test/suite/rpl/t/rpl_do_grant.test:
Added missing sync_slave_with_master; Fixes random failures
Had to explictely do stop slave before DROP USER to avoid failure on slave as the user is already dropped on slave.
mysql-test/suite/rpl/t/rpl_name_const.test:
Added missing sync_slave_with_master; Fixes random failures
mysql-test/suite/rpl/t/rpl_row_basic_11bugs.test:
Added missing sync_slave_with_master; Fixes random failures
mysql-test/t/bug47671-master.opt:
default-character-set -> character-set-server (removes warning in error files for usage of deprecated options)
mysql-test/t/ctype_latin1_de-master.opt:
default-character-set -> character-set-server (removes warning in error files for usage of deprecated options)
mysql-test/t/ctype_ucs2_def-master.opt:
default-character-set -> character-set-server (removes warning in error files for usage of deprecated options)
sql-common/client.c:
Fixed compiler warning
sql/item.cc:
Renamed function to remove compiler warnings (with gcc)
sql/item.h:
Renamed function to remove compiler warnings (with gcc)
sql/item_cmpfunc.cc:
Renamed function to remove compiler warnings (with gcc)
sql/item_create.cc:
Renamed function to remove compiler warnings (with gcc)
sql/item_create.h:
Renamed function to remove compiler warnings (with gcc)
sql/item_sum.cc:
Renamed function to remove compiler warnings (with gcc)
sql/item_sum.h:
Renamed function to remove compiler warnings (with gcc)
sql/set_var.cc:
Don't use bit_do_set() / bot_is_set() / bit_do_clear() as this generates compiler warnings
(They are also of no use as we know the value can hold the bits)
sql/sql_yacc.yy:
Renamed function to remove compiler warnings (with gcc)
storage/example/ha_example.h:
Fixed old read_time() prototype
storage/maria/ma_search.c:
Added extra variables to remove compiler warnings
storage/maria/maria_def.h:
Added extra variables to remove compiler warnings
storage/myisam/ft_stopwords.c:
Added cast to get rid of compiler warning
storage/xtradb/fil/fil0fil.c:
Added cast to get rid of compiler warning
storage/xtradb/include/page0page.h:
Added const to get rid of compiler warning
storage/xtradb/include/page0page.ic:
Added const to get rid of compiler warning
support-files/compiler_warnings.supp:
Added suppression of strict-aliasing
Post-push fix: Removed MTRv1 arguments according to the
original patch. Although there is a version check, the patch
was pushed to a 5.1 GA staging tree, while the version check
considers version 5.2. This makes the deprecated parameters
to be used, despite the fact that they are not valid anymore.
Part of MTRv1 is currently used in RQG semisync test, and this
was causing the test to fail on slave startup.
It should be safe to uncomment when merging up to celosia.
