LOCK_THREAD_COUNT
When using the performance schema file io instrumentation in MySQL 5.5,
a thread would loop forever inside lf_pinbox_put_pins, when disconnecting.
It would also hold LOCK_thread_count while doing so, effectively killing the
server.
The root cause of the loop in lf_pinbox_put_pins() is a leak of LF_PINS,
when used with the filename_hash LF_HASH table in the performance schema.
This fix contains the following changes:
1)
Added the missing call to lf_hash_search_unpin(), to prevent the leak.
2)
In mysys/lf_alloc-pin.c, there was some extra debugging code
(MY_LF_EXTRA_DEBUG) written to detect precisely this kind of issues,
but it was never used.
Replaced MY_LF_EXTRA_DEBUG with DBUG_OFF, so that leaks similar to this one
can be always detected in regular debug builds.
3)
Backported the fix for the following bug, from 5.6 to 5.5:
Bug#13417446 - 63339: INCORRECT FILE PATH IN PEFORMANCE_SCHEMA ON WINDOWS
This fix is a follow up on the fix for similar issue 56761.
When sanitizing data read from the events_waits_history_long table,
the code needs also to sanitize the schema_name / object_name / file_name pointers,
because such pointers could also hold invalid values.
Checking the string length alone was required but not sufficient.
This fix verifies that:
- the table schema and table name used in table io events
- the file name used in file io events
are valid pointers before dereferencing these pointers.
Fix various mismatches between function's language linkage. Any
particular function that is declared in C++ but should be callable
from C must have C linkage. Note that function types with different
linkages are also distinct. Thus, if a function type is declared in
C code, it will have C linkage (same if declared in a extern "C"
block).
This patch:
- Moves all definitions from the mysql_priv.h file into
header files for the component where the variable is
defined
- Creates header files if the component lacks one
- Eliminates all include directives from mysql_priv.h
- Eliminates all circular include cycles
- Rename time.cc to sql_time.cc
- Rename mysql_priv.h to sql_priv.h
The unit test pfs_instr-t:
- generates a very long (10,000) bytes file name
- calls find_or_create_file.
This leads to a buffer overflow in mysys in my_realpath(),
because my_realpath and mysys file APIs in general do not
test for input parameters: mysys assumes every file name
is less that FN_REFLEN in length.
Calling find_or_create_file with a very long file name is likely
to happen when instrumenting third party code that does not use mysys,
so this test is legitimate.
The fix is to make find_or_create_file in the performance schema
more robust in this case.
Fixed the missing initialization of locker_lost.
This fix is not strictly necessary, but is desirable to re-align the code
from 5.5 and 6.0, and reduce the spurious code differences.
This will facilitate maintenance and help to apply patches cleanly, for merges.
Before this fix, the performance schema file instrumentation would treat:
- a relative path to a file
- an absolute path to the same file
as two different files.
This would lead to:
- separate aggregation counters
- file leaks when a file is removed.
With this fix, a relative and absolute path are resolved to the same file instrument.
