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- 1.2.1 feature: negative caching for failed queries.

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Queries that failed are cached for 5 seconds (NORR_TTL).
	  If the failure is local, like out of memory, it is not cached.
	- the TTL comparison for the cache used different comparisons,
	  causing many cache responses that used the iterator and validator
	  state machines unnecessarily.



git-svn-id: file:///svn/unbound/trunk@1432 be551aaa-1e26-0410-a405-d3ace91eadb9
This commit is contained in:
Wouter Wijngaards 2009-01-14 09:38:15 +00:00
parent 5aa65f431b
commit 900142fb79
3 changed files with 38 additions and 2 deletions
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2
daemon/worker.c
View file

@ -537,7 +537,7 @@ answer_from_cache(struct worker* worker, struct query_info* qinfo,
int secure;
int must_validate = !(flags&BIT_CD) && worker->env.need_to_validate;
/* see if it is possible */
if(rep->ttl <= timenow) {
if(rep->ttl < timenow) {
/* the rrsets may have been updated in the meantime.
* we will refetch the message format from the
* authoritative server

8
doc/Changelog
View file

@ -1,3 +1,11 @@
14 January 2009: Wouter
- 1.2.1 feature: negative caching for failed queries.
Queries that failed are cached for 5 seconds (NORR_TTL).
If the failure is local, like out of memory, it is not cached.
- the TTL comparison for the cache used different comparisons,
causing many cache responses that used the iterator and validator
state machines unnecessarily.
13 January 2009: Wouter
- fixed bug in lameness marking, removed printouts.
- find NS rrset more cleanly for qtype NS.

30
iterator/iterator.c
View file

@ -229,6 +229,34 @@ error_response(struct module_qstate* qstate, int id, int rcode)
return 0;
}
/**
* Return an error to the client and cache the error code in the
* message cache (so per qname, qtype, qclass).
* @param qstate: our query state
* @param id: module id
* @param rcode: error code (DNS errcode).
* @return: 0 for use by caller, to make notation easy, like:
* return error_response(..).
*/
static int
error_response_cache(struct module_qstate* qstate, int id, int rcode)
{
/* store in cache */
struct reply_info err;
memset(&err, 0, sizeof(err));
err.flags = BIT_QR | BIT_RA;
FLAGS_SET_RCODE(err.flags, rcode);
err.qdcount = 1;
err.ttl = NORR_TTL;
/* do not waste time trying to validate this servfail */
err.security = sec_status_indeterminate;
verbose(VERB_ALGO, "store error response in message cache");
if(!iter_dns_store(qstate->env, &qstate->qinfo, &err, 0)) {
log_err("error_response_cache: could not store error (nomem)");
}
return error_response(qstate, id, rcode);
}
/** check if prepend item is duplicate item */
static int
prepend_is_duplicate(struct ub_packed_rrset_key** sets, size_t to,
@ -1308,7 +1336,7 @@ processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq,
"returning SERVFAIL");
/* fail -- no more targets, no more hope
* of targets, no hope of a response. */
return error_response(qstate, id,
return error_response_cache(qstate, id,
LDNS_RCODE_SERVFAIL);
}
}