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MXS-1804: Fix hanging of large session commands

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Large session commands weren't properly handled which caused the router to
think that the trailing end of a multi-packet query was actually a new
query.

This cannot be confidently solved in 2.2 which is why the router session
is now closed the moment a large session command is noticed.
This commit is contained in:
Markus Mäkelä
2018-04-17 14:57:54 +03:00
parent 232f807ef3
commit 3a1c2119fb
4 changed files with 67 additions and 12 deletions
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31
server/modules/routing/readwritesplit/rwsplit_route_stmt.cc
View File

@ -290,6 +290,18 @@ bool route_single_stmt(RWSplit *inst, RWSplitSession *rses, GWBUF *querybuf, con
return succp;
}
static inline bool is_large_query(GWBUF* buf)
{
uint32_t buflen = gwbuf_length(buf);
// The buffer should contain at most (2^24 - 1) + 4 bytes ...
ss_dassert(buflen <= MYSQL_HEADER_LEN + GW_MYSQL_MAX_PACKET_LEN);
// ... and the payload should be buflen - 4 bytes
ss_dassert(MYSQL_GET_PAYLOAD_LEN(GWBUF_DATA(buf)) == buflen - MYSQL_HEADER_LEN);
return buflen == MYSQL_HEADER_LEN + GW_MYSQL_MAX_PACKET_LEN;
}
/**
* Execute in backends used by current router session.
* Save session variable commands to router session property
@ -313,6 +325,13 @@ bool route_single_stmt(RWSplit *inst, RWSplitSession *rses, GWBUF *querybuf, con
bool route_session_write(RWSplitSession *rses, GWBUF *querybuf,
uint8_t command, uint32_t type)
{
if (is_large_query(querybuf))
{
MXS_ERROR("Session command is too large, session cannot continue. "
"Large session commands are not supported in 2.2.");
return false;
}
/** The SessionCommand takes ownership of the buffer */
uint64_t id = rses->sescmd_count++;
mxs::SSessionCommand sescmd(new mxs::SessionCommand(querybuf, id));
@ -1120,18 +1139,6 @@ static inline bool query_creates_reply(uint8_t cmd)
cmd != MXS_COM_STMT_CLOSE;
}
static inline bool is_large_query(GWBUF* buf)
{
uint32_t buflen = gwbuf_length(buf);
// The buffer should contain at most (2^24 - 1) + 4 bytes ...
ss_dassert(buflen <= MYSQL_HEADER_LEN + GW_MYSQL_MAX_PACKET_LEN);
// ... and the payload should be buflen - 4 bytes
ss_dassert(MYSQL_GET_PAYLOAD_LEN(GWBUF_DATA(buf)) == buflen - MYSQL_HEADER_LEN);
return buflen == MYSQL_HEADER_LEN + GW_MYSQL_MAX_PACKET_LEN;
}
/**
* @brief Handle writing to a target server
*