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MXS-1412: while discarding a result set don't buffer any data.

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MXS-1412: while discarding a result set don't buffer any data: this
avoids to store useless data.

Additionally the colum definitions buffer is used instead of the offset
value.
This commit is contained in:
MassimilianoPinto
2017-09-15 12:05:28 +02:00
parent 8905c3aa34
commit 9dd7f2174c
1 changed files with 45 additions and 24 deletions
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69
server/modules/filter/maxrows/maxrows.c
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@ -185,8 +185,8 @@ typedef struct maxrows_response_state
size_t n_fields; /**< How many fields we have received, <= n_totalfields. */
size_t n_rows; /**< How many rows we have received. */
size_t offset; /**< Where we are in the response buffer. */
size_t rows_offset; /**< Offset to first row in result set */
size_t length; /**< Buffer size. */
GWBUF* column_defs; /**< Buffer with result set columns definitions */
} MAXROWS_RESPONSE_STATE;
static void maxrows_response_state_reset(MAXROWS_RESPONSE_STATE *state);
@ -415,8 +415,18 @@ static int clientReply(MXS_FILTER *instance,
if (csdata->res.data)
{
gwbuf_append(csdata->res.data, data);
csdata->res.length += gwbuf_length(data);
if (csdata->discard_resultset &&
csdata->state == MAXROWS_EXPECTING_ROWS)
{
gwbuf_free(csdata->res.data);
csdata->res.data = data;
csdata->res.length = gwbuf_length(data);
}
else
{
gwbuf_append(csdata->res.data, data);
csdata->res.length += gwbuf_length(data);
}
}
else
{
@ -495,7 +505,6 @@ static void diagnostics(MXS_FILTER *instance, MXS_FILTER_SESSION *sdata, DCB *dc
dcb_printf(dcb, "Maxrows filter is working\n");
}
/**
* Capability routine.
*
@ -520,7 +529,7 @@ static void maxrows_response_state_reset(MAXROWS_RESPONSE_STATE *state)
state->n_fields = 0;
state->n_rows = 0;
state->offset = 0;
state->rows_offset = 0;
state->column_defs = NULL;
}
/**
@ -599,16 +608,18 @@ static int handle_expecting_fields(MAXROWS_SESSION_DATA *csdata)
case 0xfe: // EOF, the one after the fields.
csdata->res.offset += packetlen;
/* Now set the offset to the first resultset
* this could be used for empty response handler
/**
* Set the buffer with column definitions.
* This will be used only by the empty response handler.
*/
if (!csdata->res.rows_offset)
if (!csdata->res.column_defs &&
csdata->instance->config.m_return == MAXROWS_RETURN_EMPTY)
{
csdata->res.rows_offset = csdata->res.offset;
csdata->res.column_defs = gwbuf_clone(csdata->res.data);
}
csdata->state = MAXROWS_EXPECTING_ROWS;
rv = handle_rows(csdata, csdata->res.data,csdata->res.offset);
rv = handle_rows(csdata, csdata->res.data, csdata->res.offset);
break;
default: // Field information.
@ -641,11 +652,6 @@ static int handle_expecting_nothing(MAXROWS_SESSION_DATA *csdata)
if ((int)MYSQL_GET_COMMAND(GWBUF_DATA(csdata->res.data)) == 0xff)
{
/**
* Error text message is after:
* MYSQL_HEADER_LEN offset + status flag (1) + error code (2) +
* 6 bytes message status = MYSQL_HEADER_LEN + 9
*/
MXS_INFO("Error packet received from backend "
"(possibly a server shut down ?): [%s].",
GWBUF_DATA(csdata->res.data) + MYSQL_HEADER_LEN + 9);
@ -1016,12 +1022,20 @@ static int send_upstream(MAXROWS_SESSION_DATA *csdata)
ss_dassert(csdata->res.data != NULL);
/* Free a saved SQL not freed by send_error_upstream() */
if (csdata->input_sql)
if (csdata->instance->config.m_return == MAXROWS_RETURN_ERR)
{
gwbuf_free(csdata->input_sql);
csdata->input_sql = NULL;
}
/* Free a saved columndefs not freed by send_eof_upstream() */
if (csdata->instance->config.m_return == MAXROWS_RETURN_EMPTY)
{
gwbuf_free(csdata->res.column_defs);
csdata->res.column_defs = NULL;
}
/* Send data to client */
int rv = csdata->up.clientReply(csdata->up.instance,
csdata->up.session,
csdata->res.data);
@ -1046,22 +1060,24 @@ static int send_eof_upstream(MAXROWS_SESSION_DATA *csdata)
/* Sequence byte is #3 */
uint8_t eof[MYSQL_EOF_PACKET_LEN] = {05, 00, 00, 01, 0xfe, 00, 00, 02, 00};
GWBUF *new_pkt = NULL;
ss_dassert(csdata->res.data != NULL);
ss_dassert(csdata->res.column_defs != NULL);
/**
* The offset to server reply pointing to
* next byte after column definitions EOF
* of the first result set.
*/
size_t offset = csdata->res.rows_offset;
ss_dassert(csdata->res.data != NULL);
size_t offset = gwbuf_length(csdata->res.column_defs);
/* Data to send + added EOF */
uint8_t *new_result = MXS_MALLOC(offset + MYSQL_EOF_PACKET_LEN);
if (new_result)
{
/* Get contiguous data from beginning to specified offset */
gwbuf_copy_data(csdata->res.data, 0, offset, new_result);
/* Get contiguous data from saved columns defintions buffer */
gwbuf_copy_data(csdata->res.column_defs, 0, offset, new_result);
/* Increment sequence number for the EOF being added for empty resultset:
* last one if found in EOF terminating column def
@ -1094,9 +1110,12 @@ static int send_eof_upstream(MAXROWS_SESSION_DATA *csdata)
rv = 0;
}
/* Free full input buffer */
/* Free all data buffers */
gwbuf_free(csdata->res.data);
gwbuf_free(csdata->res.column_defs);
csdata->res.data = NULL;
csdata->res.column_defs = NULL;
return rv;
}
@ -1134,6 +1153,8 @@ static int send_ok_upstream(MAXROWS_SESSION_DATA *csdata)
int rv = csdata->up.clientReply(csdata->up.instance,
csdata->up.session,
packet);
/* Free server result buffer */
gwbuf_free(csdata->res.data);
csdata->res.data = NULL;
@ -1215,10 +1236,10 @@ static int send_error_upstream(MAXROWS_SESSION_DATA *csdata)
/* Free server result buffer */
gwbuf_free(csdata->res.data);
csdata->res.data = NULL;
/* Free input_sql buffer */
gwbuf_free(csdata->input_sql);
csdata->res.data = NULL;
csdata->input_sql = NULL;
return rv;