GENERATED BY THE EXP() FUNCTION
When generating the error message for numeric overflow, pass a flag to
Item::print() that prevents it from expanding constant expressions and
parameters to the values they evaluate to.
For consistency, also pass the flag to Item::print() when
Item_func_spatial_collection::fix_length_and_dec() generates an error
message. It doesn't make any difference at the moment, since constant
expressions haven't been evaluated yet when this function is called.
Description: The command FLUSH DES_KEY_FILE is expected to
reload the DES keys from the file that was specified with
the "--des-key-file" option at server startup. But it is not
behaving as expected.
Analysis: The des file reload is defined within a wrong
conditional directive, rendering the command ineffective.
Macro "OPENSSL" was used instead of "HAVE_OPENSSL" macro.
Fix: "OPENSSL" macro is changed to "HAVE_OPENSSL".
Description:
THREAD_CONCURRENCY is deprecated and there is no
deprecation warning message while setting this variable
while starting the server.
Analysis:
This variable is specific to Solaris 8 and earlier systems
and is ignored on all other platforms. But since many
customers, who uses other than Solaris, still has this
variable in their configuration file, it is important to
have a deprecation warning.
Fix:
THREAD_CONCURRENCY deprecation warning message is added.
Description:
THREAD_CONCURRENCY is deprecated and there is no
deprecation warning message while setting this variable
while starting the server.
Analysis:
This variable is specific to Solaris 8 and earlier systems
and is ignored on all other platforms. But since many
customers, who uses other than Solaris, still has this
variable in their configuration file, it is important to
have a deprecation warning.
Fix:
THREAD_CONCURRENCY deprecation warning message is added.
SHOW PROCESSLIST, SHOW BINLOGS
Problem: A deadlock was occurring when 4 threads were
involved in acquiring locks in the following way
Thread 1: Dump thread ( Slave is reconnecting, so on
Master, a new dump thread is trying kill
zombie dump threads. It acquired thread's
LOCK_thd_data and it is about to acquire
mysys_var->current_mutex ( which LOCK_log)
Thread 2: Application thread is executing show binlogs and
acquired LOCK_log and it is about to acquire
LOCK_index.
Thread 3: Application thread is executing Purge binary logs
and acquired LOCK_index and it is about to
acquire LOCK_thread_count.
Thread 4: Application thread is executing show processlist
and acquired LOCK_thread_count and it is
about to acquire zombie dump thread's
LOCK_thd_data.
Deadlock Cycle:
Thread 1 -> Thread 2 -> Thread 3-> Thread 4 ->Thread 1
The same above deadlock was observed even when thread 4 is
executing 'SELECT * FROM information_schema.processlist' command and
acquired LOCK_thread_count and it is about to acquire zombie
dump thread's LOCK_thd_data.
Analysis:
There are four locks involved in the deadlock. LOCK_log,
LOCK_thread_count, LOCK_index and LOCK_thd_data.
LOCK_log, LOCK_thread_count, LOCK_index are global mutexes
where as LOCK_thd_data is local to a thread.
We can divide these four locks in two groups.
Group 1 consists of LOCK_log and LOCK_index and the order
should be LOCK_log followed by LOCK_index.
Group 2 consists of other two mutexes
LOCK_thread_count, LOCK_thd_data and the order should
be LOCK_thread_count followed by LOCK_thd_data.
Unfortunately, there is no specific predefined lock order defined
to follow in the MySQL system when it comes to locks across these
two groups. In the above problematic example,
there is no problem in the way we are acquiring the locks
if you see each thread individually.
But If you combine all 4 threads, they end up in a deadlock.
Fix:
Since everything seems to be fine in the way threads are taking locks,
In this patch We are changing the duration of the locks in Thread 4
to break the deadlock. i.e., before the patch, Thread 4
('show processlist' command) mysqld_list_processes()
function acquires LOCK_thread_count for the complete duration
of the function and it also acquires/releases
each thread's LOCK_thd_data.
LOCK_thread_count is used to protect addition and
deletion of threads in global threads list. While show
process list is looping through all the existing threads,
it will be a problem if a thread is exited but there is no problem
if a new thread is added to the system. Hence a new mutex is
introduced "LOCK_thd_remove" which will protect deletion
of a thread from global threads list. All threads which are
getting exited should acquire LOCK_thd_remove
followed by LOCK_thread_count. (It should take LOCK_thread_count
also because other places of the code still thinks that exit thread
is protected with LOCK_thread_count. In this fix, we are changing
only 'show process list' query logic )
(Eg: unlink_thd logic will be protected with
LOCK_thd_remove).
Logic of mysqld_list_processes(or file_schema_processlist)
will now be protected with 'LOCK_thd_remove' instead of
'LOCK_thread_count'.
Now the new locking order after this patch is:
LOCK_thd_remove -> LOCK_thd_data -> LOCK_log ->
LOCK_index -> LOCK_thread_count
SHOW PROCESSLIST, SHOW BINLOGS
Problem: A deadlock was occurring when 4 threads were
involved in acquiring locks in the following way
Thread 1: Dump thread ( Slave is reconnecting, so on
Master, a new dump thread is trying kill
zombie dump threads. It acquired thread's
LOCK_thd_data and it is about to acquire
mysys_var->current_mutex ( which LOCK_log)
Thread 2: Application thread is executing show binlogs and
acquired LOCK_log and it is about to acquire
LOCK_index.
Thread 3: Application thread is executing Purge binary logs
and acquired LOCK_index and it is about to
acquire LOCK_thread_count.
Thread 4: Application thread is executing show processlist
and acquired LOCK_thread_count and it is
about to acquire zombie dump thread's
LOCK_thd_data.
Deadlock Cycle:
Thread 1 -> Thread 2 -> Thread 3-> Thread 4 ->Thread 1
The same above deadlock was observed even when thread 4 is
executing 'SELECT * FROM information_schema.processlist' command and
acquired LOCK_thread_count and it is about to acquire zombie
dump thread's LOCK_thd_data.
Analysis:
There are four locks involved in the deadlock. LOCK_log,
LOCK_thread_count, LOCK_index and LOCK_thd_data.
LOCK_log, LOCK_thread_count, LOCK_index are global mutexes
where as LOCK_thd_data is local to a thread.
We can divide these four locks in two groups.
Group 1 consists of LOCK_log and LOCK_index and the order
should be LOCK_log followed by LOCK_index.
Group 2 consists of other two mutexes
LOCK_thread_count, LOCK_thd_data and the order should
be LOCK_thread_count followed by LOCK_thd_data.
Unfortunately, there is no specific predefined lock order defined
to follow in the MySQL system when it comes to locks across these
two groups. In the above problematic example,
there is no problem in the way we are acquiring the locks
if you see each thread individually.
But If you combine all 4 threads, they end up in a deadlock.
Fix:
Since everything seems to be fine in the way threads are taking locks,
In this patch We are changing the duration of the locks in Thread 4
to break the deadlock. i.e., before the patch, Thread 4
('show processlist' command) mysqld_list_processes()
function acquires LOCK_thread_count for the complete duration
of the function and it also acquires/releases
each thread's LOCK_thd_data.
LOCK_thread_count is used to protect addition and
deletion of threads in global threads list. While show
process list is looping through all the existing threads,
it will be a problem if a thread is exited but there is no problem
if a new thread is added to the system. Hence a new mutex is
introduced "LOCK_thd_remove" which will protect deletion
of a thread from global threads list. All threads which are
getting exited should acquire LOCK_thd_remove
followed by LOCK_thread_count. (It should take LOCK_thread_count
also because other places of the code still thinks that exit thread
is protected with LOCK_thread_count. In this fix, we are changing
only 'show process list' query logic )
(Eg: unlink_thd logic will be protected with
LOCK_thd_remove).
Logic of mysqld_list_processes(or file_schema_processlist)
will now be protected with 'LOCK_thd_remove' instead of
'LOCK_thread_count'.
Now the new locking order after this patch is:
LOCK_thd_remove -> LOCK_thd_data -> LOCK_log ->
LOCK_index -> LOCK_thread_count
This is a backport of the patch of bug#11765785. Commit message
by Prabakaran Thirumalai from bug#11765785 is reproduced below:
Description:
------------
Global Query ID (global_query_id ) is not incremented for PING and
statistics command. These two query types are filtered before
incrementing the global query id. This causes race condition and
results in duplicate query id for different queries originating from
different connections.
Analysis:
---------
sqlparse.cc::dispath_command() is the only place in code which sets
thd->query_ id to global_query_id and then increments it based on the
query type. In all other places it is incremented first and then
assigned to thd->query_id.
This is done such that global_query_id is not incremented for PING
and statistics commands in dispatch_command() function.
Fix:
----
As per suggestion from Serg, "There is no reason to skip query_id for
the PING and STATISTICS command.", removing the check which filters
PING and statistics commands.
Instead of using get_query_id() and next_query_id() which can still
cause race condition if context switch happens soon after executing
get_query_id(), changing the code to use next_query_id() instead of
get_query_id() as it is done in other parts of code which deals with
global_query_id.
Removed get_query_id() function and forced next_query_id() caller
to use the return value by specifying warn_unused_result attribute.
This is a backport of the patch of bug#11765785. Commit message
by Prabakaran Thirumalai from bug#11765785 is reproduced below:
Description:
------------
Global Query ID (global_query_id ) is not incremented for PING and
statistics command. These two query types are filtered before
incrementing the global query id. This causes race condition and
results in duplicate query id for different queries originating from
different connections.
Analysis:
---------
sqlparse.cc::dispath_command() is the only place in code which sets
thd->query_ id to global_query_id and then increments it based on the
query type. In all other places it is incremented first and then
assigned to thd->query_id.
This is done such that global_query_id is not incremented for PING
and statistics commands in dispatch_command() function.
Fix:
----
As per suggestion from Serg, "There is no reason to skip query_id for
the PING and STATISTICS command.", removing the check which filters
PING and statistics commands.
Instead of using get_query_id() and next_query_id() which can still
cause race condition if context switch happens soon after executing
get_query_id(), changing the code to use next_query_id() instead of
get_query_id() as it is done in other parts of code which deals with
global_query_id.
Removed get_query_id() function and forced next_query_id() caller
to use the return value by specifying warn_unused_result attribute.
file_logger became the service.
Data like query_id now are sent to the audit plugin.
Fix for MDEV-4770 ported from 10.0.
Fix added for the read_maria_plugin_info().
Log rotation can be disabled with 'set rotations=0'.
PROBLEM:
When large number of connections are continuously made
with wait_timeout of 600 seconds for some hours, some
connections remain after wait_timeout expired and also
new connections get struck under the configuration and
the scenario reported in bug#16196591.
FIX:
The cause of this bug is the issue identified and fixed in
the BUG#16088658 in 5.6.Also LOCK_thread_count contention
issue fixed in BUG#15921866 in 5.6 need to be in 5.5 as
well. Since the issue is not reproducible, it has been
verified at customer configuration the issue could not
be reproduced after a 48-hour test with a non-debug build
which includes the above two fixes backported.
PROBLEM:
When large number of connections are continuously made
with wait_timeout of 600 seconds for some hours, some
connections remain after wait_timeout expired and also
new connections get struck under the configuration and
the scenario reported in bug#16196591.
FIX:
The cause of this bug is the issue identified and fixed in
the BUG#16088658 in 5.6.Also LOCK_thread_count contention
issue fixed in BUG#15921866 in 5.6 need to be in 5.5 as
well. Since the issue is not reproducible, it has been
verified at customer configuration the issue could not
be reproduced after a 48-hour test with a non-debug build
which includes the above two fixes backported.
- Added --verbose to BUILD scripts to get make to write out compile commands.
- Detect if AM_EXTRA_MAKEFLAGS=VERBOSE=1 was used with build scripts.
- Don't write warnings about replication variables when doing bootstrap.
- Fixed that mysql_cond_wait() and mysql_cond_timedwait() will report original source file in case of errors.
- Ignore some compiler warnings
BUILD/FINISH.sh:
Detect if AM_EXTRA_MAKEFLAGS=VERBOSE=1 or --verbose was used
BUILD/SETUP.sh:
Added --verbose to print out the full compile lines
Updated help message
client/mysqltest.cc:
Fixed that one can use 'replace' with cat_file
cmake/configure.pl:
If --verbose is used, get make to write out compile commands
debian/dist/Debian/rules:
Added $AM_EXTRA_MAKEFLAGS to get VERBOSE=1 on buildbot builds
debian/dist/Ubuntu/rules:
Added $AM_EXTRA_MAKEFLAGS to get VERBOSE=1 on buildbot builds
include/my_pthread.h:
Made set_timespec_time_nsec() more portable.
include/mysql/psi/mysql_thread.h:
Fixed that mysql_cond_wait() and mysql_cond_timedwait() will report original source file in case of errors.
mysql-test/suite/innodb/r/auto_increment_dup.result:
Fixed wrong DBUG_SYNC
mysql-test/suite/innodb/t/auto_increment_dup.test:
Fixed wrong DBUG_SYNC
mysql-test/suite/perfschema/include/upgrade_check.inc:
Make test more portable for changes in *.sql files
mysql-test/suite/perfschema/r/pfs_upgrade.result:
Updated test results
mysql-test/valgrind.supp:
Ignore running Aria checkpoint thread
scripts/mysqlaccess.sh:
Changed reference of bugs database
Ensure that also client-server group is read.
sql/handler.cc:
Added missing syncpoint
sql/mysqld.cc:
Don't write warnings about replication variables when doing bootstrap
sql/mysqld.h:
Don't write warnings about replication variables when doing bootstrap
sql/rpl_rli.cc:
Don't write warnings about replication variables when doing bootstrap
sql/sql_insert.cc:
Don't mask SERVER_SHUTDOWN in insert_delayed
This is done to be able to distingush between shutdown and interrupt errors
support-files/compiler_warnings.supp:
Ignore some compiler warnings in xtradb,innobase, oqgraph, yassl, string3.h
feature_dynamic_columns,feature_fulltext,feature_gis,feature_locale,feature_subquery,feature_timezone,feature_trigger,feature_xml
Opened_views, Executed_triggers, Executed_events
Added new process status 'updating status' as part of 'freeing items'
mysql-test/r/features.result:
Test of feature_xxx status variables
mysql-test/r/mysqld--help.result:
Removed duplicated 'language' variable.
mysql-test/r/view.result:
Test of opened_views
mysql-test/suite/rpl/t/rpl_start_stop_slave.test:
Write more information on failure
mysql-test/t/features.test:
Test of feature_xxx status variables
mysql-test/t/view.test:
Test of opened_views
sql/event_scheduler.cc:
Increment executed_events status variable
sql/field.cc:
Increment status variable
sql/item_func.cc:
Increment status variable
sql/item_strfunc.cc:
Increment status variable
sql/item_subselect.cc:
Increment status variable
sql/item_xmlfunc.cc:
Increment status variable
sql/mysqld.cc:
Add new status variables to 'show status'
sql/mysqld.h:
Added executed_events
sql/sql_base.cc:
Increment status variable
sql/sql_class.h:
Add new status variables
sql/sql_parse.cc:
Added new process status 'updating status' as part of 'freeing items'
sql/sql_trigger.cc:
Increment status variable
sql/sys_vars.cc:
Increment status variable
sql/tztime.cc:
Increment status variable
IF LOCALHOST IS BOTH IPV4/IPV6 ENABLED.
The original patch removed default value of the bind-address option.
So, the default value became NULL. By coincedence NULL resolves
to 0.0.0.0 and ::, and since the server chooses first IPv4-address,
0.0.0.0 is choosen. So, there was no change in the behaviour.
This patch restores default value of the bind-address option to "0.0.0.0".
IF LOCALHOST IS BOTH IPV4/IPV6 ENABLED.
The original patch removed default value of the bind-address option.
So, the default value became NULL. By coincedence NULL resolves
to 0.0.0.0 and ::, and since the server chooses first IPv4-address,
0.0.0.0 is choosen. So, there was no change in the behaviour.
This patch restores default value of the bind-address option to "0.0.0.0".
mysql-test/suite/innodb/t/group_commit_crash.test:
remove autoincrement to avoid rbr being used for insert ... select
mysql-test/suite/innodb/t/group_commit_crash_no_optimize_thread.test:
remove autoincrement to avoid rbr being used for insert ... select
mysys/my_addr_resolve.c:
a pointer to a buffer is returned to the caller -> the buffer cannot be on the stack
mysys/stacktrace.c:
my_vsnprintf() is ok here, in 5.5
MEMORY LEAK.
Background:
- There are caches for stored functions and stored procedures (SP-cache);
- There is no similar cache for events;
- Triggers are cached together with TABLE objects;
- Those SP-caches are per-session (i.e. specific to each session);
- A stored routine is represented by a sp_head-instance internally;
- SP-cache basically contains sp_head-objects of stored routines, which
have been executed in a session;
- sp_head-object is added into the SP-cache before the corresponding
stored routine is executed;
- SP-cache is flushed in the end of the session.
The problem was that SP-cache might grow without any limit. Although this
was not a pure memory leak (the SP-cache is flushed when session is closed),
this is still a problem, because the user might take much memory by
executing many stored routines.
The patch fixes this problem in the least-intrusive way. A soft limit
(similar to the size of table definition cache) is introduced. To represent
such limit the new runtime configuration parameter 'stored_program_cache'
is introduced. The value of this parameter is stored in the new global
variable stored_program_cache_size that used to control the size of SP-cache
to overflow.
The parameter 'stored_program_cache' limits number of cached routines for
each thread. It has the following min/default/max values given from support:
min = 256, default = 256, max = 512 * 1024.
Also it should be noted that this parameter limits the size of
each cache (for stored procedures and for stored functions) separately.
The SP-cache size is checked after top-level statement is parsed.
If SP-cache size exceeds the limit specified by parameter
'stored_program_cache' then SP-cache is flushed and memory allocated for
cache objects is freed. Such approach allows to flush cache safely
when there are dependencies among stored routines.
sql/mysqld.cc:
Added global variable stored_program_cache_size to store value of
configuration parameter 'stored-program-cache'.
sql/mysqld.h:
Added declaration of global variable stored_program_cache_size.
sql/sp_cache.cc:
Extended interface for sp_cache by adding helper routine
sp_cache_enforce_limit to control size of stored routines cache for
overflow. Also added method enforce_limit into class sp_cache that
implements control of cache size for overflow.
sql/sp_cache.h:
Extended interface for sp_cache by adding standalone routine
sp_cache_enforce_limit to control size of stored routines cache
for overflow.
sql/sql_parse.cc:
Added flush of sp_cache after processing of next sql-statement
received from a client.
sql/sql_prepare.cc:
Added flush of sp_cache after preparation/execution of next prepared
sql-statement received from a client.
sql/sys_vars.cc:
Added support for configuration parameter stored-program-cache.
MEMORY LEAK.
Background:
- There are caches for stored functions and stored procedures (SP-cache);
- There is no similar cache for events;
- Triggers are cached together with TABLE objects;
- Those SP-caches are per-session (i.e. specific to each session);
- A stored routine is represented by a sp_head-instance internally;
- SP-cache basically contains sp_head-objects of stored routines, which
have been executed in a session;
- sp_head-object is added into the SP-cache before the corresponding
stored routine is executed;
- SP-cache is flushed in the end of the session.
The problem was that SP-cache might grow without any limit. Although this
was not a pure memory leak (the SP-cache is flushed when session is closed),
this is still a problem, because the user might take much memory by
executing many stored routines.
The patch fixes this problem in the least-intrusive way. A soft limit
(similar to the size of table definition cache) is introduced. To represent
such limit the new runtime configuration parameter 'stored_program_cache'
is introduced. The value of this parameter is stored in the new global
variable stored_program_cache_size that used to control the size of SP-cache
to overflow.
The parameter 'stored_program_cache' limits number of cached routines for
each thread. It has the following min/default/max values given from support:
min = 256, default = 256, max = 512 * 1024.
Also it should be noted that this parameter limits the size of
each cache (for stored procedures and for stored functions) separately.
The SP-cache size is checked after top-level statement is parsed.
If SP-cache size exceeds the limit specified by parameter
'stored_program_cache' then SP-cache is flushed and memory allocated for
cache objects is freed. Such approach allows to flush cache safely
when there are dependencies among stored routines.
Problem : The basic problem is the way the thread sleeps in mysql-5.5 and also in mysql-5.1
when we execute a stop slave on windows platform.
On windows platform if the stop slave is executed after the master dies, we have
this long wait before the stop slave return a value. This is because there is a
sleep of the thread. The sleep is uninterruptable in the two above version,
which was fixed by Davi patch for the BUG#11765860 for mysql-trunk. Backporting
his patch for mysql-5.5 fixes the problem.
Solution : A new pair of mutex and condition variable is introduced to synchronize thread
sleep and finalization. A new mutex is required because the slave threads are
terminated while holding the slave thread locks (run_lock), which can not be
relinquished during termination as this would affect the lock order.
mysql-test/suite/rpl/r/rpl_start_stop_slave.result:
The result file associated with the test added.
mysql-test/suite/rpl/t/rpl_start_stop_slave.test:
A test to check the new functionality.
sql/rpl_mi.cc:
The constructor using the new mutex and condition variables for the master_info.
sql/rpl_mi.h:
The condition variable and mutex have been added for the master_info.
sql/rpl_rli.cc:
The constructor using the new mutex and condition variables for the realy_log_info.
sql/rpl_rli.h:
The condition variable and mutex have been added for the relay_log_info.
sql/slave.cc:
Use a timed wait on a condition variable to implement a interruptible sleep.
The wait is registered with the THD object so that the thread will be woken
up if killed.
Problem : The basic problem is the way the thread sleeps in mysql-5.5 and also in mysql-5.1
when we execute a stop slave on windows platform.
On windows platform if the stop slave is executed after the master dies, we have
this long wait before the stop slave return a value. This is because there is a
sleep of the thread. The sleep is uninterruptable in the two above version,
which was fixed by Davi patch for the BUG#11765860 for mysql-trunk. Backporting
his patch for mysql-5.5 fixes the problem.
Solution : A new pair of mutex and condition variable is introduced to synchronize thread
sleep and finalization. A new mutex is required because the slave threads are
terminated while holding the slave thread locks (run_lock), which can not be
relinquished during termination as this would affect the lock order.
* rename all debugging related command-line options
and variables to start from "debug-", and made them all
OFF by default.
* replace "MySQL" with "MariaDB" in error messages
* "Cast ... converted ... integer to it's ... complement"
is now a note, not a warning
* @@query_cache_strip_comments now has a session scope,
not global.
BIN LOG HAS BEEN MOVED
When moving the binary/relay log files from one location to
another and restarting the server with a different log-bin or
relay-log paths, would cause the startup process to abort. The
root cause was that the server would not be able to find the log
files because it would consider old paths for entries in the
index file instead of the new location. What's even worse, the
relative paths would not be considered relative to the path
provided in log-bin and relay-log, but to mysql_data_dir.
We fix the cases where the server contains relative paths. When
the server is reading from the index file, it checks whether the
entry contains relative paths. If it does, we replace it with the
absolute path set in log-bin/relay-log option. Absolute paths
remain unchanged and the index must be manually edited to
consider the new log-bin and/or relay-log path (this should be
documented). This is a fix for a GA version, that does not break
behavior (that much).
For development versions, we should go with Zhenxing's approach
that removes paths altogether from index files.
mysql-test/include/begin_include_file.inc:
Added parameter to keep the begin_include_file.inc silent. Useful when
including scripts that contain platform dependent parameters, for example:
--let $rpl_server_parameters=--log-bin=$tmpdir/slave-bin --relay-log=$tmpdir/slave-relay-bin
--let $keep_include_silent=1
source include/rpl_start_server.inc;
--let $keep_include_silent=0
We want the paths ($tmpdir/slave-bin and $tmpdir/slave-relay-bin) not to be in the
result file.
mysql-test/suite/rpl/t/rpl_binlog_index.test:
Test case.
sql/log.cc:
When finding the corresponding log entry in the index file, we first
normalize the paths before doing the comparison. This will make relative
paths to be turned into absolute paths (based on the opt_bin_logname or
opt_relay_logname) and then compared against also, expanded paths entered,
through CHANGE MASTER for instance.
sql/log.h:
Added normalize_binlog_name, which turns relative paths, into absolute paths
given the parameter: is_relay_log ? opt_relay_logname : opt_bin_logname .
sql/mysqld.cc:
Exposing opt_bin_logname.
sql/mysqld.h:
Exposing opt_bin_logname.
BIN LOG HAS BEEN MOVED
When moving the binary/relay log files from one location to
another and restarting the server with a different log-bin or
relay-log paths, would cause the startup process to abort. The
root cause was that the server would not be able to find the log
files because it would consider old paths for entries in the
index file instead of the new location. What's even worse, the
relative paths would not be considered relative to the path
provided in log-bin and relay-log, but to mysql_data_dir.
We fix the cases where the server contains relative paths. When
the server is reading from the index file, it checks whether the
entry contains relative paths. If it does, we replace it with the
absolute path set in log-bin/relay-log option. Absolute paths
remain unchanged and the index must be manually edited to
consider the new log-bin and/or relay-log path (this should be
documented). This is a fix for a GA version, that does not break
behavior (that much).
For development versions, we should go with Zhenxing's approach
that removes paths altogether from index files.
