odyssey/sources/reset.c

144 lines
3.4 KiB
C

/*
* Odyssey.
*
* Scalable PostgreSQL connection pooler.
*/
#include <stdlib.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <inttypes.h>
#include <assert.h>
#include <machinarium.h>
#include <kiwi.h>
#include <odyssey.h>
int
od_reset(od_server_t *server)
{
od_instance_t *instance = server->global->instance;
od_route_t *route = server->route;
/* server left in copy mode */
if (server->is_copy) {
od_log(&instance->logger, "reset", server->client, server,
"in copy, closing");
goto drop;
}
/* support route rollback off */
if (! route->rule->pool_rollback) {
if (server->is_transaction) {
od_log(&instance->logger, "reset", server->client, server,
"in active transaction, closing");
goto drop;
}
}
/* Server is not synchronized.
*
* Number of queries sent to server is not equal
* to the number of received replies. Do the following
* logic until server becomes synchronized:
*
* 1. Wait each ReadyForQuery until we receive all
* replies with 1 sec timeout.
*
* 2. Send Cancel in other connection.
*
* It is possible that client could previously
* pipeline server with requests. Each request
* may stall database on its own way and may require
* additional Cancel request.
*
* 3. Continue with (1)
*/
int wait_timeout = 1000;
int wait_try = 0;
int wait_try_cancel = 0;
int wait_cancel_limit = 1;
int rc = 0;
for (;;)
{
/* check that msg syncronization is not broken*/
if (server->relay.packet > 0)
goto error;
while (! od_server_synchronized(server)) {
od_debug(&instance->logger, "reset", server->client, server,
"not synchronized, wait for %d msec (#%d)",
wait_timeout,
wait_try);
wait_try++;
rc = od_backend_ready_wait(server, "reset", 1, wait_timeout);
if (rc == -1)
break;
}
if (rc == -1) {
if (! machine_timedout())
goto error;
/* support route cancel off */
if (! route->rule->pool_cancel) {
od_log(&instance->logger, "reset", server->client, server,
"not synchronized, closing");
goto drop;
}
if (wait_try_cancel == wait_cancel_limit) {
od_error(&instance->logger, "reset", server->client, server,
"server cancel limit reached, closing");
goto error;
}
od_log(&instance->logger, "reset", server->client, server,
"not responded, cancel (#%d)",
wait_try_cancel);
wait_try_cancel++;
rc = od_cancel(server->global,
route->rule->storage, &server->key,
&server->id);
if (rc == -1)
goto error;
continue;
}
assert(od_server_synchronized(server));
break;
}
od_debug(&instance->logger, "reset", server->client, server,
"synchronized");
/* send rollback in case server has an active
* transaction running */
if (route->rule->pool_rollback) {
if (server->is_transaction) {
char query_rlb[] = "ROLLBACK";
rc = od_backend_query(server, "reset-rollback", query_rlb,
sizeof(query_rlb), wait_timeout);
if (rc == -1)
goto error;
assert(! server->is_transaction);
}
}
/* send DISCARD ALL */
if (route->rule->pool_discard) {
char query_discard[] = "DISCARD ALL";
rc = od_backend_query(server, "reset-discard", query_discard,
sizeof(query_discard), wait_timeout);
if (rc == -1)
goto error;
}
/* ready */
return 1;
drop:
return 0;
error:
return -1;
}