Systemd has a socket activation feature where a mariadb.socket
definition defines the sockets to listen to, and passes those
file descriptors directly to mariadbd to use when a connection
occurs.
The new functionality is utilized when starting as follows:
systemctl start mariadb.socket
The mariadb.socket definition only needs to contain the network
information, ListenStream= directives, the mariadb.service
definition is still used for service instigation.
When mariadbd is started in this way, the socket, port, bind-address
backlog are all assumed to be self contained in the mariadb.socket
definition and as such the mariadb settings and command line
arguments of these network settings are ignored.
See man systemd.socket for how to limit this to specific ports.
Extra ports, those specified with extra_port in socket activation
mode, are those with a FileDescriptorName=extra. These need
to be in a separate service name like mariadb-extra.socket and
these require a Service={mariadb.service} directive to map to the
original service. Extra ports need systemd v227 or greater
(not RHEL/Centos7 - v219) when FileDescriptorName= was added,
otherwise the extra ports are treated like ordinary ports.
The number of sockets isn't limited when using systemd socket activation
(except by operating system limits on file descriptors and a minimal
amount of memory used per file descriptor). The systemd sockets passed
can include any ownership or permissions, including those the
mariadbd process wouldn't normally have the permission to create.
This implementation is compatible with mariadb.service definitions.
Those services started with:
systemctl start mariadb.service
does actually start the mariadb.service and used all the my.cnf
settings of sockets and ports like it previously did.
accept might return an error, including SOCKET_EAGAIN/
SOCKET_EINTR. The caller, usually handle_connections_sockets
can these however and invalid file descriptor isn't something
to call fcntl on.
Thanks to Etienne Guesnet (ATOS) for diagnosis,
sample patch description and testing.
Performance schema likely/unlikely assume that performance schema
is enabled by default, which causes a performance degradation for
default installations that doesn't have performance schema enabled.
Fixed by changing the likely/unlikely in PS to assume it's
not enabled. This can be changed by compiling with
-DPSI_ON_BY_DEFAULT
Other changes:
- Added psi_likely/psi_unlikely that is depending on
PSI_ON_BY_DEFAULT. psi_likely() is assumed to be true
if PS is enabled.
- Added likely/unlikely to some PS interface code.
- Moved pfs_enabled to mysys (was initialized but not used before)
- Added "if (pfs_likely(pfs_enabled))" around calls to PS to avoid
an extra call if PS is not enabled.
- Moved checking flag_global_instrumention before other flags
to speed up the case when PS is not enabled.
In MDEV-8743, the port/socket of mysqld was changed to set FD_CLOEXEC.
The existing mysql_socket_socket function already set that with
SOCK_CLOEXEC when the socket was created. So here we move the fcntl
functionality to the mysql_socket_socket as port/socket are the only
callers.
Preprocessor checks of SOCK_CLOEXEC cannot be done as its a 0 if not
there and SOCK_CLOEXEC (being the value of the enum in bits/socket_type.h)
Preprocesssor logic for arithmetic and non-arithmetic defines are
hard/nonportable/ugly to read. As such we just check in my_global.h
and define HAVE_SOCK_CLOEXEC if we have it.
There was a disparity in behaviour between defined(WITH_WSREP) and
not depending on the OS, so the WITH_WSREP condition was removed
from setting calling fcntl.
All sockets are now maked SOCK_CLOEXEC/FD_CLOEXEC.
strace of mysqld with SOCK_CLOEXEC:
socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC, IPPROTO_TCP) = 10
write(2, "180419 14:52:40 [Note] Server socket created on IP: '127.0.0.1'.\n", 65180419 14:52:40 [Note] Server socket created on IP: '127.0.0.1'.
) = 65
setsockopt(10, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
bind(10, {sa_family=AF_INET, sin_port=htons(16020), sin_addr=inet_addr("127.0.0.1")}, 16) = 0
listen(10, 150) = 0
socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC, IPPROTO_TCP) = 11
write(2, "180419 14:52:40 [Note] Server socket created on IP: '127.0.0.1'.\n", 65180419 14:52:40 [Note] Server socket created on IP: '127.0.0.1'.
) = 65
setsockopt(11, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
bind(11, {sa_family=AF_INET, sin_port=htons(16021), sin_addr=inet_addr("127.0.0.1")}, 16) = 0
listen(11, 150) = 0
socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0) = 12
unlink("/home/dan/repos/build-mariadb-server-10.0/mysql-test/var/tmp/mysqld.1.sock") = -1 ENOENT (No such file or directory)
setsockopt(12, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
umask(000) = 006
bind(12, {sa_family=AF_UNIX, sun_path="/home/dan/repos/build-mariadb-server-10.0/mysql-test/var/tmp/mysqld.1.sock"}, 110) = 0
umask(006) = 000
listen(12, 150) = 0
Handle string length as size_t, consistently (almost always:))
Change function prototypes to accept size_t, where in the past
ulong or uint were used. change local/member variables to size_t
when appropriate.
This fix excludes rocksdb, spider,spider, sphinx and connect for now.
Define my_thread_id as an unsigned type, to avoid mismatch with
ulonglong. Change some parameters to this type.
Use size_t in a few more places.
Declare many flag constants as unsigned to avoid sign mismatch
when shifting bits or applying the unary ~ operator.
When applying the unary ~ operator to enum constants, explictly
cast the result to an unsigned type, because enum constants can
be treated as signed.
In InnoDB, change the source code line number parameters from
ulint to unsigned type. Also, make some InnoDB functions return
a narrower type (unsigned or uint32_t instead of ulint;
bool instead of ibool).
Creating a CONNECT object on client connect and pass this to the working thread which creates the THD.
Split LOCK_thread_count to different mutexes
Added LOCK_thread_start to syncronize threads
Moved most usage of LOCK_thread_count to dedicated functions
Use next_thread_id() instead of thread_id++
Other things:
- Thread id now starts from 1 instead of 2
- Added cast for thread_id as thread id is now of type my_thread_id
- Made THD->host const (To ensure it's not changed)
- Removed some DBUG_PRINT() about entering/exiting mutex as these was already logged by mutex code
- Fixed that aborted_connects and connection_errors_internal are counted in all cases
- Don't take locks for current_linfo when we set it (not needed as it was 0 before)
