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https://issues.apache.org/jira/browse/TS-4331?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15351295#comment-15351295
]
ASF GitHub Bot commented on TS-4331:
------------------------------------
Github user jacksontj commented on a diff in the pull request:
https://github.com/apache/trafficserver/pull/653#discussion_r68602238
--- Diff: iocore/hostdb/HostDB.cc ---
@@ -300,131 +237,77 @@ HostDBProcessor::cache()
return &hostDB;
}
-struct HostDBTestRR : public Continuation {
- int fd;
- char b[512];
- int nb;
- int outstanding, success, failure;
- int in;
-
- int
- mainEvent(int event, Event *e)
- {
- if (event == EVENT_INTERVAL) {
- printf("HostDBTestRR: %d outstanding %d succcess %d failure\n",
outstanding, success, failure);
- }
- if (event == EVENT_HOST_DB_LOOKUP) {
- --outstanding;
- if (e)
- ++success;
- else
- ++failure;
- }
- if (in)
- return EVENT_CONT;
- in = 1;
- while (outstanding < 40) {
- if (!nb)
- goto Lreturn;
- char *end = (char *)memchr(b, '\n', nb);
- if (!end)
- read_some();
- end = (char *)memchr(b, '\n', nb);
- if (!end)
- nb = 0;
- else {
- *end = 0;
- outstanding++;
- hostDBProcessor.getbyname_re(this, b, 0);
- nb -= ((end + 1) - b);
- memcpy(b, end + 1, nb);
- if (!nb)
- read_some();
- }
- }
- Lreturn:
- in = 0;
- return EVENT_CONT;
- }
-
- void
- read_some()
- {
- nb = read(fd, b + nb, 512 - nb);
- ink_release_assert(nb >= 0);
- }
-
- HostDBTestRR() : Continuation(new_ProxyMutex()), nb(0), outstanding(0),
success(0), failure(0), in(0)
- {
- printf("starting HostDBTestRR....\n");
- fd = open("hostdb_test.config", O_RDONLY, 0);
- ink_release_assert(fd >= 0);
- read_some();
- SET_HANDLER(&HostDBTestRR::mainEvent);
- }
-
- ~HostDBTestRR() { close(fd); }
-};
-
-struct HostDBSyncer : public Continuation {
+struct HostDBBackgroundTask : public Continuation {
int frequency;
ink_hrtime start_time;
- int sync_event(int event, void *edata);
+ virtual int sync_event(int event, void *edata) = 0;
int wait_event(int event, void *edata);
- HostDBSyncer();
+ HostDBBackgroundTask(int frequency);
};
-HostDBSyncer::HostDBSyncer() : Continuation(new_ProxyMutex()),
frequency(0), start_time(0)
+HostDBBackgroundTask::HostDBBackgroundTask(int frequency) :
Continuation(new_ProxyMutex()), frequency(frequency), start_time(0)
{
- SET_HANDLER(&HostDBSyncer::sync_event);
+ SET_HANDLER(&HostDBBackgroundTask::sync_event);
}
int
-HostDBSyncer::sync_event(int, void *)
+HostDBBackgroundTask::wait_event(int, void *)
{
- SET_HANDLER(&HostDBSyncer::wait_event);
- start_time = Thread::get_hrtime();
- hostDBProcessor.cache()->sync_partitions(this);
- return EVENT_DONE;
-}
+ ink_hrtime next_sync = HRTIME_SECONDS(this->frequency) -
(Thread::get_hrtime() - start_time);
-int
-HostDBSyncer::wait_event(int, void *)
-{
- ink_hrtime next_sync = HRTIME_SECONDS(hostdb_sync_frequency) -
(Thread::get_hrtime() - start_time);
-
- SET_HANDLER(&HostDBSyncer::sync_event);
+ SET_HANDLER(&HostDBBackgroundTask::sync_event);
if (next_sync > HRTIME_MSECONDS(100))
eventProcessor.schedule_in(this, next_sync, ET_TASK);
else
eventProcessor.schedule_imm(this, ET_TASK);
return EVENT_DONE;
}
+struct HostDBSync : public HostDBBackgroundTask {
+ std::string storage_path;
+ std::string full_path;
+ HostDBSync(int frequency, std::string storage_path, std::string
full_path)
+ : HostDBBackgroundTask(frequency), storage_path(storage_path),
full_path(full_path){};
+ int
+ sync_event(int, void *)
+ {
+ SET_HANDLER(&HostDBSync::wait_event);
+ start_time = Thread::get_hrtime();
+
+ new RefCountCacheSync<RefCountCache<HostDBInfo>>(this,
hostDBProcessor.cache()->refcountcache, this->frequency,
+ this->storage_path,
this->full_path);
+ return EVENT_DONE;
+ }
+};
+
int
HostDBCache::start(int flags)
{
- Store *hostDBStore;
- Span *hostDBSpan;
+ (void)flags; // unused
char storage_path[PATH_NAME_MAX];
- int storage_size = 33554432; // 32MB default
-
- bool reconfigure = ((flags & PROCESSOR_RECONFIGURE) ? true : false);
- bool fix = ((flags & PROCESSOR_FIX) ? true : false);
+ int hostdb_max_size = 33554432; // 32MB default
+ int hostdb_partitions = 64;
storage_path[0] = '\0';
// Read configuration
// Command line overrides manager configuration.
//
REC_ReadConfigInt32(hostdb_enable, "proxy.config.hostdb");
- REC_ReadConfigString(hostdb_filename, "proxy.config.hostdb.filename",
sizeof(hostdb_filename));
- REC_ReadConfigInt32(hostdb_size, "proxy.config.hostdb.size");
REC_ReadConfigInt32(hostdb_srv_enabled, "proxy.config.srv_enabled");
REC_ReadConfigString(storage_path, "proxy.config.hostdb.storage_path",
sizeof(storage_path));
- REC_ReadConfigInt32(storage_size, "proxy.config.hostdb.storage_size");
+ REC_ReadConfigString(hostdb_filename, "proxy.config.hostdb.filename",
sizeof(hostdb_filename));
+
+ // Max number of items
+ REC_ReadConfigInt32(hostdb_max_count, "proxy.config.hostdb.max_count");
+ // max size allowed to use
+ REC_ReadConfigInt32(hostdb_max_size, "proxy.config.hostdb.max_size");
--- End diff --
Well, these are actually set in the default config options. So i'll set the
default here in the code to -1, but either way the config option will overwrite
it.
> Hostdb consistency problems due to MultiCache
> ---------------------------------------------
>
> Key: TS-4331
> URL: https://issues.apache.org/jira/browse/TS-4331
> Project: Traffic Server
> Issue Type: Bug
> Components: HostDB
> Reporter: Thomas Jackson
> Assignee: Thomas Jackson
> Fix For: 7.0.0
>
>
> This ticket is for the correct long term fix to TS-4207
> pulled from a comment, which wraps up the issue
> {quote}
> Leif Hedstrom I have spent a decent amount of time on this while I was OOO on
> vacation the last couple of weeks. It seems that the root cause of this issue
> has always existed, and that the addition of always doing hostname storing
> (https://github.com/apache/trafficserver/commit/0e703e1e) we are just causing
> the issue to happen all the time.
> To understand the issue I'll give a little background in how hostdb is
> currently working. Basically hostdb is just a wrapper around this templated
> struct called MultiCache. MultiCache is "multi" not because it is templated,
> but because it has two types of storage (static-- blocks and dynamic--
> alloc). The static side of the cache can hold N HostDBInfo structs (the
> results of DNS queries). The dynamic side is used to store the round robin
> records and various strings associated with the record. The size of this
> dynamic space is defined as (N x [estimated_heap_bytes_per_entry. The basic
> problem we are running into is that we are putting too much preassure on the
> dynamic heap-- such that the heap is getting re-used while people still have
> references to items in that space.
> So, I've actually been working on re-writing MultiCache to allocate the
> entire required block at once (so we don't have this problem where the parent
> exists but not the children), but I'm not certain if we want such a change to
> go into the 6.x branch (I'm willing to discuss if we want). If we aren't
> comfortable with such a large change I suggest just accounting for the
> hostname size in the estimated_heap_bytes_per_entry as a stopgap solution.
> The maximum allowable size is 253 (so 254 with null terminator), but we could
> pick a smaller number (~120 or so seems to be more reasonable). Alternatively
> you can increase the number of records in hostdb (and the size accordingly)
> to increase the dynamic heap size.
> TLDR; almost done with the long term solution, but I'm not sure if we want to
> merge that into 6.x-- alternatively we can do a simple workaround in 6.x
> (https://github.com/apache/trafficserver/pull/553)
> {quote}
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