Optimize lookup

Fix potential case when varnish stops responding with a large number of bans and variations

Author: sobolevsv

.gitignore

@@ -6,6 +6,7 @@ Makefile.in
 _*
 .deps/
 .libs/
+.vscode/
 *.o
 *.a
 *.lo

bin/varnishd/cache/cache_hash.c

@@ -451,12 +451,6 @@ HSH_Lookup(struct req *req, struct objcore **ocp, struct objcore **bocp)
 		if (oc->ttl <= 0.)
 			continue;
 
-		if (BAN_CheckObject(wrk, oc, req)) {
-			oc->flags |= OC_F_DYING;
-			EXP_Remove(oc, NULL);
-			continue;
-		}
-
 		if (!req->hash_ignore_vary && ObjHasAttr(wrk, oc, OA_VARY)) {
 			vary = ObjGetAttr(wrk, oc, OA_VARY, NULL);
 			AN(vary);
@@ -466,6 +460,12 @@ HSH_Lookup(struct req *req, struct objcore **ocp, struct objcore **bocp)
 			}
 		}
 
+		if (BAN_CheckObject(wrk, oc, req)) {
+			oc->flags |= OC_F_DYING;
+			EXP_Remove(oc, NULL);
+			continue;
+		}
+
 		if (req->vcf != NULL) {
 			vr = req->vcf->func(req, &oc, &exp_oc, 0);
 			if (vr == VCF_CONTINUE)

bin/varnishtest/tests/c00133.vtc

@@ -0,0 +1,86 @@
+varnishtest "Optimized HSH_Lookup - ban is checked after Vary is matched"
+
+server s1 {
+	rxreq
+	expect req.url == /foo
+	expect req.http.foobar == "1"
+	txresp -hdr "Vary: Foobar" -body "1111"
+
+	rxreq
+	expect req.url == /foo
+	expect req.http.foobar == "2"
+	txresp -hdr "Vary: Foobar" -body "2222"
+
+	rxreq
+	expect req.url == /foo
+	expect req.http.foobar == "3"
+	txresp -hdr "Vary: Foobar" -body "3333"
+
+	rxreq
+	expect req.url == /foo
+	expect req.http.foobar == "1"
+	txresp -hdr "Vary: Foobar" -body "1111"
+
+	rxreq
+	expect req.url == /foo
+	expect req.http.foobar == "1"
+	txresp -hdr "Vary: Foobar" -body "1111"	
+
+} -start
+
+varnish v1 -vcl+backend {
+	sub vcl_backend_response {
+		set beresp.http.url = bereq.url;
+	}
+} -start
+
+
+client c1 {
+	txreq -url /foo -hdr "Foobar: 1"
+	rxresp
+	expect resp.body == "1111"
+} -run
+
+client c1 {
+	txreq -url /foo -hdr "Foobar: 2" 
+	rxresp
+	expect resp.body == "2222"
+} -run
+
+client c1 {
+	txreq -url /foo -hdr "Foobar: 3" 
+	rxresp
+	expect resp.body == "3333"
+
+} -run
+
+varnish v1 -expect n_object == 3
+varnish v1 -expect cache_hit == 0
+varnish v1 -expect cache_miss == 3
+
+client c1 {
+	txreq -url /foo -hdr "Foobar: 1"
+	rxresp
+} -run
+
+varnish v1 -expect cache_hit == 1
+varnish v1 -expect cache_miss == 3
+
+varnish v1 -cliok "ban obj.http.url == /foo"
+varnish v1 -cliok "ban obj.http.url == /bar"
+varnish v1 -cliok "ban obj.http.url == /baz"
+
+client c1 {
+	txreq -url /foo -hdr "Foobar: 1"
+	rxresp
+} -run
+
+varnish v1 -expect bans_tested == 1
+varnish v1 -expect bans_tests_tested == 3
+varnish v1 -expect bans_obj_killed == 1
+varnish v1 -expect n_object == 3
+
+
+varnish v1 -expect cache_hit == 1
+varnish v1 -expect cache_miss == 4
+varnish v1 -expect client_req == 5