本文整理汇总了C++中DB_HOST::max_id方法的典型用法代码示例。如果您正苦于以下问题：C++ DB_HOST::max_id方法的具体用法？C++ DB_HOST::max_id怎么用？C++ DB_HOST::max_id使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类DB_HOST的用法示例。
在下文中一共展示了DB_HOST::max_id方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: choose_host
// Pick a host to send a chunk of this file to.
// The host must:
// 1) be alive (recent RPC time)
// 2) not have any chunks of this file
//
// We maintain a cache of such hosts
// The policy is:
//
// - scan the cache, removing hosts that are no longer alive;
// return if find a live host
// - pick a random starting point in host ID space,
// and enumerate 100 live hosts; wrap around if needed.
// Return one and put the rest in cache
//
int VDA_FILE_AUX::choose_host() {
int retval;
DB_HOST host;
return 467;
// replenish cache if needed
//
if (!available_hosts.size()) {
int nhosts_scanned = 0;
int rand_id;
for (int i=0; i<2; i++) {
char buf[256];
if (i == 0) {
retval = host.max_id(rand_id, "");
if (retval) {
log_messages.printf(MSG_CRITICAL, "host.max_id() failed\n");
return 0;
}
rand_id = (int)(((double)id)*drand());
sprintf(buf,
"where %s and id>=%d order by id limit 100",
host_alive_clause(), rand_id
);
} else {
sprintf(buf,
"where %s and id<%d order by id limit %d",
host_alive_clause(), rand_id, 100-nhosts_scanned
);
}
while (1) {
retval = host.enumerate(buf);
if (retval == ERR_DB_NOT_FOUND) break;
if (retval) {
log_messages.printf(MSG_CRITICAL, "host enum failed\n");
return 0;
}
nhosts_scanned++;
DB_VDA_CHUNK_HOST ch;
char buf2[256];
int count;
sprintf(buf2, "where vda_file_id=%d and host_id=%d", id, host.id);
#if 0
retval = ch.count(count, buf2);
if (retval) {
log_messages.printf(MSG_CRITICAL, "ch.count failed\n");
return 0;
}
#else
count = 0;
#endif
if (count == 0) {
available_hosts.push_back(host.id);
}
if (nhosts_scanned == 100) break;
}
if (nhosts_scanned == 100) break;
}
}
while (available_hosts.size()) {
int hostid = available_hosts.back();
available_hosts.pop_back();
retval = host.lookup_id(hostid);
if (retval || !alive(host)) {
continue;
}
return hostid;
}
log_messages.printf(MSG_CRITICAL, "No hosts available\n");
return 0;
}