We introduce the following settable Boolean global variables:
innodb_log_file_write_through: Whether writes to ib_logfile0 are
write-through (disabling any caching, as in O_SYNC or O_DSYNC).
innodb_data_file_write_through: Whether writes to any InnoDB data files
(including the temporary tablespace) are write-through.
innodb_data_file_buffering: Whether the file system cache is enabled
for InnoDB data files.
All these parameters are OFF by default, that is, the file system cache
will be disabled, but any hardware caching is enabled, that is,
explicit calls to fsync(), fdatasync() or similar functions are needed.
On systems that support FUA it may make sense to enable write-through,
to avoid extra system calls.
If the deprecated read-only start-up parameter is set to one of the
following values, then the values of the 4 Boolean flags (the above 3
plus innodb_log_file_buffering) will be set as follows:
O_DSYNC:
innodb_log_file_write_through=ON, innodb_data_file_write_through=ON,
innodb_data_file_buffering=OFF, and
(if supported) innodb_log_file_buffering=OFF.
fsync, littlesync, nosync, or (Microsoft Windows specific) normal:
innodb_log_file_write_through=OFF, innodb_data_file_write_through=OFF,
and innodb_data_file_buffering=ON.
Note: fsync() or fdatasync() will only be disabled if the separate
parameter debug_no_sync (in the code, my_disable_sync) is set.
In mariadb-backup, the parameter innodb_flush_method will be ignored.
The Boolean parameters can be modified by SET GLOBAL while the
server is running. This will require reopening the ib_logfile0
or all currently open InnoDB data files.
We will open files straight in O_DSYNC or O_SYNC mode when applicable.
Data files we will try to open straight in O_DIRECT mode when the
page size is at least 4096 bytes. For atomically creating data files,
we will invoke os_file_set_nocache() to enable O_DIRECT afterwards,
because O_DIRECT is not supported on some file systems. We will also
continue to invoke os_file_set_nocache() on ib_logfile0 when
innodb_log_file_buffering=OFF can be fulfilled.
For reopening the ib_logfile0, we use the same logic that was developed
for online log resizing and reused for updates of
innodb_log_file_buffering.
Reopening all data files is implemented in the new function
fil_space_t::reopen_all().
Reviewed by: Vladislav Vaintroub
Tested by: Matthias Leich
An unfortunate change to the default behavior of the handling of
core dumps was implemented in
commit e9be5428a2
by making MTR_PRINT_CORE=small the default value, that is, to
only display the stack trace of one thread in crash reports.
Many if not most failures that occur in regression tests are
sporadic and involve race conditions or deadlocks. To be able to
analyze such failures, having the stack traces of all active threads
is a must, because CI environments typically do not save any core dumps.
While the environment variable MTR_PRINT_CORE could be set in CI
environments to compensate for the unfortunate change, it is better
to revert to the old default (dumping all threads) so that
no explicit action will be required from maintainers of independent
CI systems. In that case, if something fails once in a blue moon,
we can have some hope of diagnosing it based on the output.
We fix this regression by defaulting the unset environment variable
MTR_PRINT_CORE to "medium".
first SIGTERM and if the process didn't die in 10 seconds, SIGKILL it.
This allows various tools like `rr`, `gcov`, `gprof`, etc to flush
their data to disk properly
66832e3a introduced change that prints core dumps in very detailed
format. That's completely out of user-friendliness but serves as a
measure for debugging hard-reproducible bugs.
The proper way to implement this:
1. it must be controlled by command-line and environment variable;
2. detailed traces must be default for buildbots only, for user
invocations normal stack traces should be printed.
Options for control are: MTR_PRINT_CORE and --print-core that accept
the following values:
no Don't print core
short Print stack trace of failed thread
medium Print stack traces of all threads
detailed Print all stack traces with debug context
custom:<code> Use debugger commands <code> to print stack trace
Default setting is: short (see env_or_default() call in pre_setup())
For environment variable wrong values are silently ignored (falls back
to default setting, see env_or_default()).
Command-line option --print-core (or -C) overrides environment
variable. Its default value is 'short' if not specified explicitly
(same env_or_default() call in pre_setup()). Explicit values are
checked for validity.
--print-method option can specify by which debugger we print
cores. For Windows there is only one choice: cdb. For Unix the values
are: gdb, dbx, lldb, auto. Default value is: auto
In 'auto' we try to use all possible debuggers until success.
setup_boot_args(), setup_client_args(), setup_args() traversing
datastructures on each invocation. Even if performance is not
important to perl script (though it definitely saves some CO2), this
nonetheless provokes some code-reading questions. Reading and
debugging such code is not convenient.
The better way is to prepare all the data in advance in an easily
readable form as well as do the validation step before any further
processing.
Use mtr_report() instead of die() like the other code does.
TODO: do_args() does even more data processing magic. Prepare that
data according the above strategy in advance in pre_setup() if possible.
Summary of changes
- MD_CTX_SIZE is increased
- EVP_CIPHER_CTX_buf_noconst(ctx) does not work anymore, points
to nobody knows where. The assumption made previously was that
(since the function does not seem to be documented)
was that it points to the last partial source block.
Add own partial block buffer for NOPAD encryption instead
- SECLEVEL in CipherString in openssl.cnf
had been downgraded to 0, from 1, to make TLSv1.0 and TLSv1.1 possible
(according to https://github.com/openssl/openssl/blob/openssl-3.0.0/NEWS.md
even though the manual for SSL_CTX_get_security_level claims that it
should not be necessary)
- Workaround Ssl_cipher_list issue, it now returns TLSv1.3 ciphers,
in addition to what was set in --ssl-cipher
- ctx_buf buffer now must be aligned to 16 bytes with openssl(
previously with WolfSSL only), ot crashes will happen
- updated aes-t , to be better debuggable
using function, rather than a huge multiline macro
added test that does "nopad" encryption piece-wise, to test
replacement of EVP_CIPHER_CTX_buf_noconst
part of MDEV-29000
Summary of changes
- MD_CTX_SIZE is increased
- EVP_CIPHER_CTX_buf_noconst(ctx) does not work anymore, points
to nobody knows where. The assumption made previously was that
(since the function does not seem to be documented)
was that it points to the last partial source block.
Add own partial block buffer for NOPAD encryption instead
- SECLEVEL in CipherString in openssl.cnf
had been downgraded to 0, from 1, to make TLSv1.0 and TLSv1.1 possible
(according to https://github.com/openssl/openssl/blob/openssl-3.0.0/NEWS.md
even though the manual for SSL_CTX_get_security_level claims that it
should not be necessary)
- Workaround Ssl_cipher_list issue, it now returns TLSv1.3 ciphers,
in addition to what was set in --ssl-cipher
- ctx_buf buffer now must be aligned to 16 bytes with openssl(
previously with WolfSSL only), ot crashes will happen
- updated aes-t , to be better debuggable
using function, rather than a huge multiline macro
added test that does "nopad" encryption piece-wise, to test
replacement of EVP_CIPHER_CTX_buf_noconst
part of MDEV-28133
bt full - to include args and locals.
set print sevenbit on
- it is more useful to be able to see the exact bytes
(in case something is dumped as a string and not hexadecimal digits)
set print static-members off
- there are many interesting (non-const) static members
set frame-arguments all
- even non-printables are useful to see.
Let's make our bb logs give a little bit more detail on those
hard to reproduce bugs.
Tests on rhel7's gdb-7.6.1-120.el7
mtr detects a forced combination if the command line for a test already
includes all options from this combination. options are stored in a perl
hash as (key,value) pairs.
this breaks if the command line has two options with the same name,
like --plugin-load-add=foo --plugin-load-add=bar, and the combination
forces plugin foo.
In particular, this resulted in warnings when running
federated.federatedx_versioning test
There is a server startup option --gdb a.k.a. --debug-gdb that requests
signals to be set for more convenient debugging. Most notably, SIGINT
(ctrl-c) will not be ignored, and you will be able to interrupt the
execution of the server while GDB is attached to it.
When we are debugging, the signal handlers that would normally display
a terse stack trace are useless.
When we are debugging with rr, the signal handlers may interfere with
a SIGKILL that could be sent to the process by the environment, and ruin
the rr replay trace, due to a Linux kernel bug
https://lkml.org/lkml/2021/10/31/311
To be able to diagnose bugs in kill+restart tests, we may really need
both a trace before the SIGKILL and a trace of the failure after a
subsequent server startup. So, we had better avoid hitting the problem
by simply not installing those signal handlers.
