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.
(make relies GNU extentions). The patch was partially
backport from 6.0.
Original comment:
bug#30708: make relies GNU extensions. Now that we no longer use
BitKeeper we can safely remove the SCCS handling with no loss of
functionality.
3321 Magnus Blåudd 2010-01-05
BUG#44840 - ndbapi compiler warning - type qualifier ignored for function return type
- Remove the "const"
- NOTE! This is an ABI incompatible change for some C++ compilers, NdbApi applications
using any of the four changed functions may need a recompile if it's using dynamic linking.
STRING_RESULT argument
There is a "magic" number for precision : NOT_FIXED_DEC.
This means that the precision is not a fixed number.
But this constant was re-defined in several files and
was not available to the UDF developers.
Moved the NOT_FIXED_DEC definition to the correct header
and removed the redundant definitions.
Backported to 5.6.0 (mysql-next-mr-runtime)
STRING_RESULT argument
There is a "magic" number for precision : NOT_FIXED_DEC.
This means that the precision is not a fixed number.
But this constant was re-defined in several files and
was not available to the UDF developers.
Moved the NOT_FIXED_DEC definition to the correct header
and removed the redundant definitions.
Add a check if setting an auto_increment field will change it's next value before retrieving tuple_id_range lock. This avoids hitting locks when updating auto_increment values to a lower value than the current maximum. This is useful in loading a table with auto_increment where one loads the highest numbered pk's first and then proceeds backwards to the first. This can then be achieved with the same performance as a normal insert without auto_increment.
ndb_restore.result:
Updated result file
