Rwsplit handles ERRACT_NEW_CONNECTION by clearing backend reference, removing callbacks and associating backend reference with new backend server. If it succeeds and the router session can continue, handleError returns true. Otherwise false. When ever false is returned it means that session must be closed.
Rwsplit now tolerates backend failures in a way that it searches new backends when monitor, backend, or client operation fails due to backend failure.
Added a lot of logging to error, trace and message logs which should help the user to handle errors which can't be automatically resolved, like attempt to use nonexisting database.
Maintenance mode prevents a server from having new connections made
to it and stops MaxScale from monitoring a server. It is designed
to allow a server to be taken out of an active cluster for maintenance.
It prevents new connections and allowsg existing connections to
drain away prior to performaing maintenance on the server.
be extracted from the modules.
This gives a way to verify the API that the module provides as well
as the version of that API. The hope is that this will make it possible
for MaxScale to detect out of date plugins and either adapt to use them
or reject loading them.
Also added the ability to set a release state on a per module basis.
This allows for production ready and non-production ready plugins to
be identified.
Parameter it read from config file to CONFIG_CONTEXT's parameter list. It is qualified in service.c:service_set_slave_conn_limit and if qualified, the qualified integer value and the value type are copied to the CONFIG_PARAMETER structure.
This CONFIG_PARAMETER struct is cloned (=copied to different memory area) and linked to RW Split SERVICE struct.
When RW Split router_instance is created in readwritesplit.c:createInstance, the value is copied to (new) rwsplit_config_t structure from SERVICE's parameter list.
When new routing session is created in readwritesplit.c:newSession, the rwsplit_config_t structure is copied to ROUTER_CLIENT_SES struct and the actual max_nslaves value is calculated from the config value (if percentage is used).
Tests and many error handling branches are missing but functionality seems to be working.
nection router stream is used and with read/write split router individual statements are passed to router.
Added new function to ROUTER_OBJECT : uint8_t (*getCapabilities)(ROUTER *instance, void* router_session); which is implemented in every route
r.
Added support for multi-statement packets in rwsplit router. In other words, if network packet includes multiple mysql statements, they are separated and passed to router one by one.
Multi-packet statements (those which exceeds network packet boundaries) are _not_ supported yet.
Session commands are identified by query clasisfier, and added to the session command property list in router client session object.
Session commands are then executed in existing backend servers but only one of them will reply to client.
Added new argument '-s' which takes additional argument composed of list of logfile identifiers. Logfiles listed with '-s' will be written on main memory instead of disk. In practice, the log file in question will be written in /dev/shm but corresponding symlink is added to log directory. In the case of name conflicts with log files and links, a differentiating sequence number is included in hte name of the file. This, however, is done only when existing file is not writable or is of different type (symlink <> file).
Added new logfile LOGFILE_DEBUG whose contents will be largerly what was included up to date in trace log.
Disabled feature which spreads writes to log files to others because of bug (#338) in the way block buffers are managed.
Changed log manager parameters to match with the current implementation. List of arguments:
"-h - help\n"
"-a <debug prefix> ............(\"skygw_debug\")\n"
"-b <debug suffix> ............(\".log\")\n"
"-c <trace prefix> ............(\"skygw_trace\")\n"
"-d <trace suffix> ............(\".log\")\n"
"-e <message prefix> ............(\"skygw_msg\")\n"
"-f <message suffix> ............(\".log\")\n"
"-g <error prefix> ............(\"skygw_err\")\n"
"-i <error suffix> ............(\".log\")\n"
"-j <log path> ............(\"/tmp\")\n"
"-s <shmem log file ids> ........(no default)\n";
dcb.c
dcb_add_to_zombieslist, add dcb to the front of zombies list instead of inserting to the end of it.
gateway.c
Renamed shutdown_gateway to shutdown_server (Bug #131)
Call skygw_logmanager_init so that trace and debug logs are written to shared memory.
poll.c
dcb.h
Removed some dead code and references to unneeded mutexes.
debugcmd.c
Added enable/disable log command for debug log.
skygw_utils.cc
skygw_file_init now takes optional symlink name as a second argument. Symlink is created to point to the file being created.
resolve_query_type, added GSYSVAR_FUNC type for functions that read system variables and can be executed in Maxscale instead of backend server.
dcb.c
dcb_read, if read returns value <= 0 and if error is EAGAIN/EWOULDBLOCK so there was nothing to read in sthe socket, that is not an error because some other thread may have read the data that was expected to be available.
mysql_backend.c
gw_read_backend_event, used dcb->authlock to ensure that dcb's protocol state is read and modified serially. This removes issues with false authentication failures which may happen when two threads modify and read the state without any control.
mysql_client.c
removed dead code.
readconnroute.c, readwritesplit.c
removed invalid assert which assumed that spinlock can not have larger value than one when itis locked.
poll.c
Removed mutex from epoll_wait.
Removed read and write mutexes from poll_waitevents.
session.c
If session_alloc fails, instead of calling directly free(session), call session_free, which decreases refcounter and only frees session when there are no references left.
Added session_unlink_dcb function which removes link from session and optionally sets the dcb->session pointer to NULL.
readconnection.h, readwritesplit.h
Added check fields to ROUTER_CLIENT_SES strct as well as lock, version number (not used yet) and closed flag.
mysql_backend.c
gw_read_backend_event: if backend_protocol->state was set to MYSQL_AUTH_RECV, function returned, which was unnecessary. If mysql state became MYSQL_AUTH_FAILED, router client session was closed. Removed unnecessary NULL checks because rsession is not allowed to be NULL. Similarly, removed other NULL checks and replaced them with asserts checking that router client session is not NULL at any phase.
mysql_client.c
Removed unused code blocks. Polished log commands. Replaced router client sessions NULL checks with asserts.
mysql_common.c
mysql_send_custom_error: if called with dcb == NULL, return.
readconnroute.c
Replaced malloc with calloc. Added functions rses_begin_router_action and rses_exit_router_action. If router client session is not closed, they take a lock and release it, respectively. Those functions are used for protecting all operations which modify the contents of router client session struct.
readwritesplit.c
Identical changes than in readconnroute.c
skygw_debug.h
Added check number and - macro for ROUTER_CLIENT_SES, and added COM_QUIT to STRPACKETTYPE.
The routine if called from backend will ido:
1 reply error messages to client closing or not the session
2 open a new backend connection
An action flag is passed to the routine.
tuned error printing and log writing output format
dcb.c :
dcb_connect, check return value of poll_add_dcb and behave accordingly.
dcb_write, in case of SIFPIPE, only write to trace log.
dcb_close, dassert with incorrect dcb states.
gateway.c :
added file_write_header to print header similar than in logs to stderr.
main, add signal handler for SIGPIPE
poll.c :
poll_remove_dcb, don't fail if dcb is in NOPOLLING or in ZOMBIE states.
poll_waitevents, write EPOLLHUPs to trace log, don't even attempt to write to closed socket.
readconnection.h :
shortened comment.
readwritesplit.h :
replaced generic names with more specific ones.
httpd.c :
Check listen return value and behave accordingly.
mysql_backend.c :
Tiny clean up.
mysql_client.c :
gw_MySQLListener, Check listen return value and behave accordingly.
mysql_common.c :
Shortened a header.
telnetd.c :
telnetd_listen, check listen return value and behave accordingly.
readconnroute.c :
Tuned log writing format.
readwritesplit.c :
Added function search_backend_servers, which chooses suitable backend and master server among those known by Maxscale. Fixed clean-up routines. Not ready yet but works somehow.
testroute.c :
Cleanup.
skygw_utils.cc :
Log writing clean up.
dcb_final_free: Router session is not closed anymore when dcb is closed. Router session is shared among all dcbs and is closed and freed with session.
dcb_connect: dcb's state must be switched fro DCB_STATE_ALLOC to DCB_STATE_DISCONNECTED before dcb_final_free can be called for it.
dcb_close: poll_remove_dcb encapsulates dcb's state transition in the same way as poll_add_dcb. Removed state modification from dcb_close. Read return value of poll_remove_dcb and log accordingly.
dcb_set state: remove dassert if dcb_set_state_nomutex returned false. False can be returned indicating that intented change didn't occur but the end state, for example, may be acceptable. Failures in state transitions are asserted in dcb_Set_state_nomutex.
poll.c
poll_add_dcb: dcb state is now set here to either DCB_STATE_LISTENING or to DCB_STATE_POLLING according to dcb's role. Failures in state setting and in epoll_ctl are detected, logged and handled.
poll_remove_dcb: Failures in state setting and epoll_ctl are detected, logged, and handled.
mysql_client_server_protocol.h
Removed macros MYSQL_FAILED_AUTHENTICATION & MYSQL_SUCCESFUL_AUTHENTICATION as they were not necessary and used with constant values 0 and 1 depending on the case.
Renamed variable 'conn' to 'protocol' in cases where it meant protocol.
mysql_backend.c
gw_read_backend_event: In case when there was nothing to read or read failed, backend dcb is closed because situation is assumed to be such that backend server closed its side of the socket. Removed macros MYSQL_FAILED/SUCCESFUL_AUTHENTICATION
gw_create_backend_connection: Assigned protocol with fd which is connected to backend.
backend_write_delayqueue: In case where dcb_write fails to write anything, close backend dcb to avoid it getting hanging.
mysql_client.c
gw_read_client_event: Read return value of routeQuery and if it isn't == 1, call mysql_send_custom_error with client dcb and set client's protocol state to MYSQL_IDLE instead of MYSQL_ROUTING.
gw_MySQLAccept: Static reply counter was erroneously used as a criteria for jumping to return point where return value was constantly 'success' (=0). Replaced static reply counter with private. Fixed return value in different cases.
mysql_common.c
gw_receive_backend_auth: Changed to return boolean values indicating of success or failue. Used integers which were assigned to macroed values on the caller side. Added length check before accessing buffer.
readconnroute.c
Cut too long lines and removed statements with side effects.
skygw_debug.h
Added macro STRPROTOCOLSTATE(s) to produce string representation of a given protocol state.
session.c: Replaced free(session->router_sesision) with call to freeSession callback
users.c: Removed reference to uninitialized variable.
router.h: Added freeSession callback to function block.
mysql_backend.c: try to ensure that client dcb is still listening in epoll_wait when writing reply to it.
mysql_common.c: assert debug build is mysql_protocol_init is called with dcb == NULL
readconnroute.c, readwritesplit.c, debugcli.c and testroute.c : Added freeSession to function block and an inmplementation of it.
Removed freeing router session object because it is not know at this phase whether session is really closed or not. Router session can be freed only when session is.
SkySQL MaxScale Thu Aug 8 00:01:08 2013
------------------------------------------
2013 08/08 00:01:17 Selected server in port 3003 to as candidate. Connections : 0
2013 08/08 00:01:17 Examine server in port 3002 with 0 connections. Status is 5, inst->bitvalue is 6
2013 08/08 00:01:17 Examine server in port 3001 with 0 connections. Status is 5, inst->bitvalue is 6
2013 08/08 00:01:17 Examine server in port 3000 with 0 connections. Status is 3, inst->bitvalue is 6
2013 08/08 00:01:17 Final selection is server in port 3003. Connections : 1
2013 08/08 00:01:22 Selected server in port 3003 to as candidate. Connections : 1
2013 08/08 00:01:22 Examine server in port 3002 with 0 connections. Status is 5, inst->bitvalue is 6
2013 08/08 00:01:22 Examine server in port 3001 with 0 connections. Status is 5, inst->bitvalue is 6
2013 08/08 00:01:22 Examine server in port 3000 with 0 connections. Status is 3, inst->bitvalue is 6
2013 08/08 00:01:22 Final selection is server in port 3002. Connections : 1
