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MXS-185: "read-only" transactions to be directed to the slaves by the readwritesplit router

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START TRANSACTION READ ONLY
statements
COMMIT

All statements, including START … and COMMIT are routed to same slave
server
This commit is contained in:
MassimilianoPinto 2017-01-25 11:43:17 +01:00
parent 286f44ac80
commit b23d3e6198
1 changed files with 44 additions and 0 deletions
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44
server/modules/routing/readwritesplit/rwsplit_route_stmt.c
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@ -492,6 +492,19 @@ bool rwsplit_get_dcb(DCB **p_dcb, ROUTER_CLIENT_SES *rses, backend_type_t btype,
}
backend_ref = rses->rses_backend_ref;
/** Check whether using rses->forced_node as target SLAVE */
if (rses->forced_node &&
session_trx_is_read_only(rses->client_dcb->session))
{
*p_dcb = rses->forced_node->bref_dcb;
succp = true;
MXS_DEBUG("force_node found in READ ONLY transaction: use slave %s",
(*p_dcb)->server->unique_name);
goto return_succp;
}
/** get root master from available servers */
master_bref = get_root_master_bref(rses);
@ -620,6 +633,7 @@ bool rwsplit_get_dcb(DCB **p_dcb, ROUTER_CLIENT_SES *rses, backend_type_t btype,
}
}
} /*< for */
/** Assign selected DCB's pointer value */
if (candidate_bref != NULL)
{
@ -784,6 +798,11 @@ route_target_t get_route_target(ROUTER_CLIENT_SES *rses,
target = TARGET_MASTER;
}
}
else if (session_trx_is_read_only(rses->client_dcb->session))
{
/* Force TARGET_SLAVE for READ ONLY tranaction (active or ending) */
target = TARGET_SLAVE;
}
else
{
ss_dassert(trx_active || load_active ||
@ -812,6 +831,7 @@ route_target_t get_route_target(ROUTER_CLIENT_SES *rses,
qc_query_is_type(qtype, QUERY_TYPE_EXEC_STMT) ||
qc_query_is_type(qtype, QUERY_TYPE_PREPARE_STMT) ||
qc_query_is_type(qtype, QUERY_TYPE_PREPARE_NAMED_STMT));
target = TARGET_MASTER;
}
@ -1215,6 +1235,19 @@ handle_got_target(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
sescmd_cursor_t *scur;
bref = get_bref_from_dcb(rses, target_dcb);
/**
* If the transaction is READ ONLY set forced_node to bref
* That SLAVE backend will be used until COMMIT is seen
*/
if (!rses->forced_node &&
session_trx_is_read_only(rses->client_dcb->session))
{
rses->forced_node = bref;
MXS_DEBUG("Setting forced_node SLAVE to %s within an opened READ ONLY transaction\n",
target_dcb->server->unique_name);
}
scur = &bref->bref_sescmd_cur;
ss_dassert(target_dcb != NULL);
@ -1249,6 +1282,17 @@ handle_got_target(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
bref = get_bref_from_dcb(rses, target_dcb);
bref_set_state(bref, BREF_QUERY_ACTIVE);
bref_set_state(bref, BREF_WAITING_RESULT);
/**
* If a READ ONLYtransaction is ending set forced_node to NULL
*/
if (rses->forced_node &&
session_trx_is_read_only(rses->client_dcb->session) &&
session_trx_is_ending(rses->client_dcb->session))
{
MXS_DEBUG("An opened READ ONLY transaction ends: forced_node is set to NULL");
rses->forced_node = NULL;
}
return true;
}
else