tee.c:routeQuery cloned partial MySQL packets to be routed to child router. Problems were due to the use of gwbuf_clone and modutil_MySQL_query which clone/examine only the first buffer from the buffer list which composes GWBUF.
modutil.c: Added function modutil_MySQL_query_len which calculates MySQL packet length and the missing bytecount
tee.c: Added details about the freeing of orphaned sessions.
session.: Added missing cases of session state into the session_state function in debug builds.
tee.c: Created a static, module-wide list of orphaned branch sessions which holds the branch sessions that can't be freed at the
time the parent session is being freed. This list is processed every time a a tee filter session is freeing its memory.
Tee filter now receives two client replies, one from the parent service and
one from the child service. These replies are checked before cloning any more queries
into the child service. If the reply isn't sent fast enough, the child session is closed.
Added clientReply and setUpstream entry points
Tee filter now waits for the branch session to be replied to and if the reply isn't received in five seconds it closes the branch session.
dcb.h:
Added the DCBF_REPLIED flag that is currently only set in dcb_null_write
dcb.c:
The DCBF_REPLIED flag is now set in dcb_null_write
session.c:session_free:if session is child of another service (tee in this case), it is the parent which releases child's allocated memory back to the system. This now also includes the child router session.
dcb.h: Added DCB_IS_CLONE macro
tee.c:freeSession:if parent session triggered closing of tee, then child session may not be closed yet. In that case free the child session first and only then free child router session and release child session's memory back to system.
tee.c:routeQuery: only route if child session is ready for routing. Log if session is not ready for routing and set tee session inactive
mysql_client.c:gw_client_close:if DCB is cloned one don't close the protocol because they it is shared with the original DCB.
dcb.c:dcb_clone: set same close function than in the original DCB so that routing session will become closed when client DCB is closed.
session.h:introduce a new state which indicates that SESSION structure can be freed next, SESSION_STATE_TO_BE_FREED. State is needed to separate the state before and after memory free. Memory is freed in different situation depending on whether the session is parent or child session. Child sessions are freed in their parent.
Also introduce a new member in SESSION struct, ses_is_child, to indicate whether SESSION has a parent session which is responsible for releasing the memory of it.
session.c:session_unlink_dcb:when last session reference is removed set SESSION->state=SESSION_STATE_TO_BE_FREED
session.c:session_free:only free the memory if session is not child session. If it is child, session is left to be freed by the parent (in tee filter's freeSession, for example).
tee.c:newSession:mark branch session to child.
tee.c:freeSession:if child session memory is ready to be freed, free it.
mysql_mon.c:monitorMain:when backend server's status changes so that it is not running anymore or doesn't have any of the states - master, slave, ndb, joined - call for each DCB the callback-function DCB_REASON_NOT_RESPONDING if specified. Earlier callbacks were called if there was any change in the state of the server being monitored.
tee.c:closeSession removed unnecessary dcb_free, router/service closes all backend DCBs and the client DCB, and client DCB is the one that was tried to free in closeSession.
readwritesplit.c:routeQuery now handles untyped and typed GWBUFs. Untyped means that read buffer may consist of incomplete and multiple MySQL packets. Typed buffer always consists of a single MySQL packet (which can be split to many buffers inside GWBUF).
Fixed Coverity cases #84840 and #84841
