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Addition of MAXROWS_DISCARDING_RESPONSE

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Addition of MAXROWS_DISCARDING_RESPONSE

Packets received after sent OK are consumed and not sent
This commit is contained in:
MassimilianoPinto
2016-10-27 09:25:08 +02:00
parent 59b3a1fe36
commit c73c3b390a
1 changed files with 54 additions and 29 deletions
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83
server/modules/filter/maxrows/maxrows.c
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@ -132,6 +132,7 @@ typedef enum maxrows_session_state
MAXROWS_EXPECTING_ROWS, // A select has been sent, and we want more rows.
MAXROWS_EXPECTING_NOTHING, // We are not expecting anything from the server.
MAXROWS_IGNORING_RESPONSE, // We are not interested in the data received from the server.
MAXROWS_DISCARDING_RESPONSE, // We have returned empty result set and we discard any new data.
} maxrows_session_state_t;
typedef struct maxrows_response_state
@ -145,9 +146,9 @@ typedef struct maxrows_response_state
static void maxrows_response_state_reset(MAXROWS_RESPONSE_STATE *state);
typedef struct cache_session_data
typedef struct maxrows_session_data
{
MAXROWS_INSTANCE *instance; /**< The cache instance the session is associated with. */
MAXROWS_INSTANCE *instance; /**< The maxrows instance the session is associated with. */
DOWNSTREAM down; /**< The previous filter or equivalent. */
UPSTREAM up; /**< The next filter or equivalent. */
MAXROWS_RESPONSE_STATE res; /**< The response state. */
@ -169,11 +170,12 @@ static bool process_params(char **options, FILTER_PARAMETER **params, MAXROWS_CO
static int send_upstream(MAXROWS_SESSION_DATA *csdata);
static int send_ok_upstream(MAXROWS_SESSION_DATA *csdata);
static int handle_discarding_response(MAXROWS_SESSION_DATA *csdata);
/* API BEGIN */
/**
* Create an instance of the cache filter for a particular service
* Create an instance of the maxrows filter for a particular service
* within MaxScale.
*
* @param name The name of the instance (as defined in the config file).
@ -203,7 +205,7 @@ static FILTER *createInstance(const char *name, char **options, FILTER_PARAMETER
/**
* Associate a new session with this instance of the filter.
*
* @param instance The cache instance data
* @param instance The maxrows instance data
* @param session The session itself
*
* @return Session specific data for this session
@ -219,7 +221,7 @@ static void *newSession(FILTER *instance, SESSION *session)
/**
* A session has been closed.
*
* @param instance The cache instance data
* @param instance The maxrows instance data
* @param sdata The session data of the session being closed
*/
static void closeSession(FILTER *instance, void *sdata)
@ -231,7 +233,7 @@ static void closeSession(FILTER *instance, void *sdata)
/**
* Free the session data.
*
* @param instance The cache instance data
* @param instance The maxrows instance data
* @param sdata The session data of the session being closed
*/
static void freeSession(FILTER *instance, void *sdata)
@ -245,7 +247,7 @@ static void freeSession(FILTER *instance, void *sdata)
/**
* Set the downstream component for this filter.
*
* @param instance The cache instance data
* @param instance The maxrowsinstance data
* @param sdata The session data of the session
* @param down The downstream filter or router
*/
@ -260,7 +262,7 @@ static void setDownstream(FILTER *instance, void *sdata, DOWNSTREAM *down)
/**
* Set the upstream component for this filter.
*
* @param instance The cache instance data
* @param instance The maxrows instance data
* @param sdata The session data of the session
* @param up The upstream filter or router
*/
@ -320,7 +322,7 @@ static int routeQuery(FILTER *instance, void *sdata, GWBUF *packet)
if (use_default)
{
C_DEBUG("Maxrows filter is sends data.");
C_DEBUG("Maxrows filter is sending data.");
rv = csdata->down.routeQuery(csdata->down.instance, csdata->down.session, packet);
}
@ -355,11 +357,11 @@ static int clientReply(FILTER *instance, void *sdata, GWBUF *data)
if (gwbuf_length(csdata->res.data) > csdata->instance->config.max_resultset_size)
{
C_DEBUG("Current size %uB of resultset, at least as much "
"as maximum allowed size %uKiB. Not caching.",
"as maximum allowed size %uKiB. Not returning data.",
gwbuf_length(csdata->res.data),
csdata->instance->config.max_resultset_size / 1024);
csdata->state = MAXROWS_IGNORING_RESPONSE;
csdata->state = MAXROWS_DISCARDING_RESPONSE;
/* Send empty result set */
return send_ok_upstream(csdata);
@ -388,6 +390,10 @@ static int clientReply(FILTER *instance, void *sdata, GWBUF *data)
rv = handle_ignoring_response(csdata);
break;
case MAXROWS_DISCARDING_RESPONSE:
rv = handle_discarding_response(csdata);
break;
default:
MXS_ERROR("Internal filter logic broken, unexpected state: %d", csdata->state);
ss_dassert(!true);
@ -431,7 +437,7 @@ static uint64_t getCapabilities(void)
/* API END */
/**
* Reset cache response state
* Reset maxrows response state
*
* @param state Pointer to object.
*/
@ -445,9 +451,9 @@ static void maxrows_response_state_reset(MAXROWS_RESPONSE_STATE *state)
}
/**
* Create cache session data
* Create maxrows session data
*
* @param instance The cache instance this data is associated with.
* @param instance The maxrows instance this data is associated with.
*
* @return Session data or NULL if creation fails.
*/
@ -487,9 +493,9 @@ static MAXROWS_SESSION_DATA *maxrows_session_data_create(MAXROWS_INSTANCE *insta
}
/**
* Free cache session data.
* Free maxrows session data.
*
* @param A cache session data previously allocated using session_data_create().
* @param A maxrows session data previously allocated using session_data_create().
*/
static void maxrows_session_data_free(MAXROWS_SESSION_DATA* data)
{
@ -507,7 +513,7 @@ static void maxrows_session_data_free(MAXROWS_SESSION_DATA* data)
/**
* Called when resultset field information is handled.
*
* @param csdata The cache session data.
* @param csdata The maxrows session data.
*/
static int handle_expecting_fields(MAXROWS_SESSION_DATA *csdata)
{
@ -560,7 +566,7 @@ static int handle_expecting_fields(MAXROWS_SESSION_DATA *csdata)
/**
* Called when data is received (even if nothing is expected) from the server.
*
* @param csdata The cache session data.
* @param csdata The maxrows session data.
*/
static int handle_expecting_nothing(MAXROWS_SESSION_DATA *csdata)
{
@ -575,7 +581,7 @@ static int handle_expecting_nothing(MAXROWS_SESSION_DATA *csdata)
/**
* Called when a response is received from the server.
*
* @param csdata The cache session data.
* @param csdata The maxrows session data.
*/
static int handle_expecting_response(MAXROWS_SESSION_DATA *csdata)
{
@ -651,7 +657,7 @@ static int handle_expecting_response(MAXROWS_SESSION_DATA *csdata)
/**
* Called when resultset rows are handled.
*
* @param csdata The cache session data.
* @param csdata The maxrows session data.
*/
static int handle_expecting_rows(MAXROWS_SESSION_DATA *csdata)
{
@ -682,11 +688,7 @@ static int handle_expecting_rows(MAXROWS_SESSION_DATA *csdata)
csdata->res.offset += packetlen;
ss_dassert(csdata->res.offset == buflen);
/* Send data only if number of rows is below the limit */
if (csdata->state != MAXROWS_IGNORING_RESPONSE)
{
rv = send_upstream(csdata);
}
rv = send_upstream(csdata);
csdata->state = MAXROWS_EXPECTING_NOTHING;
break;
@ -698,11 +700,16 @@ static int handle_expecting_rows(MAXROWS_SESSION_DATA *csdata)
if (csdata->res.n_rows > csdata->instance->config.max_resultset_rows)
{
C_DEBUG("Max rows %lu reached, not caching result.", csdata->res.n_rows);
C_DEBUG("max_resultset_rows %lu reached, not returning the result.", csdata->res.n_rows);
/* Just return 0 result set */
rv = send_ok_upstream(csdata);
csdata->res.offset = buflen; // To abort the loop.
csdata->state = MAXROWS_IGNORING_RESPONSE;
/* If additional packets from server will come
* they will be "consumed" and not sent to client
*/
csdata->state = MAXROWS_DISCARDING_RESPONSE;
}
break;
}
@ -720,7 +727,7 @@ static int handle_expecting_rows(MAXROWS_SESSION_DATA *csdata)
/**
* Called when all data from the server is ignored.
*
* @param csdata The cache session data.
* @param csdata The maxrows session data.
*/
static int handle_ignoring_response(MAXROWS_SESSION_DATA *csdata)
{
@ -731,7 +738,7 @@ static int handle_ignoring_response(MAXROWS_SESSION_DATA *csdata)
}
/**
* Processes the cache params
* Processes the maxrows params
*
* @param options Options as passed to the filter.
* @param params Parameters as passed to the filter.
@ -847,3 +854,21 @@ static int send_ok_upstream(MAXROWS_SESSION_DATA *csdata)
return rv;
}
/**
* Called when all data from the server should be consumed and not sent.
*
* @param csdata The maxrows session data.
*/
static int handle_discarding_response(MAXROWS_SESSION_DATA *csdata)
{
ss_dassert(csdata->state == MAXROWS_DISCARDING_RESPONSE);
ss_dassert(csdata->res.data);
gwbuf_free(csdata->res.data);
csdata->res.data = NULL;
MXS_INFO("maxrows filter is receiving response packets from the backend in 'discarding_response' state.");
return 1;
}