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https://issues.apache.org/jira/browse/TS-4331?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15314870#comment-15314870
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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_r65779442
--- Diff: iocore/hostdb/HostDB.cc ---
@@ -439,37 +327,24 @@ HostDBCache::start(int flags)
Warning("Please set 'proxy.config.hostdb.storage_path' or
'proxy.config.local_state_dir'");
}
- hostDBStore = new Store;
- hostDBSpan = new Span;
- hostDBSpan->init(storage_path, storage_size);
- hostDBStore->add(hostDBSpan);
-
- Debug("hostdb", "Opening %s, size=%d", hostdb_filename, hostdb_size);
- if (open(hostDBStore, "hostdb.config", hostdb_filename, hostdb_size,
reconfigure, fix, false /* slient */) < 0) {
- ats_scoped_str rundir(RecConfigReadRuntimeDir());
- ats_scoped_str config(Layout::relative_to(rundir, "hostdb.config"));
+ // Combine the path and name
+ char full_path[2 * PATH_NAME_MAX];
--- End diff --
Yea, TBH I'm not sure why thats like that-- it was before (in a different
part of the code-- moved to here. Presumably we actually know what the size
is-- since we have the filename and path... I can definitely clean that :)
> 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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