Add an \xff keyrange that is backed by the txnStateStore.

fdbclient/SystemData.cpp

@@ -624,3 +624,8 @@ std::pair<Key,Version> decodeHealthyZoneValue( ValueRef const& value) {
 	reader >> version;
 	return std::make_pair(zoneId, version);
 }
+
+const KeyRangeRef testOnlyTxnStateStorePrefixRange(
+    LiteralStringRef("\xff/TESTONLYtxnStateStore/"),
+    LiteralStringRef("\xff/TESTONLYtxnStateStore0")
+);

fdbclient/SystemData.h

@@ -282,4 +282,8 @@ extern const KeyRef healthyZoneKey;
 const Value healthyZoneValue( StringRef const& zoneId, Version version );
 std::pair<Key,Version> decodeHealthyZoneValue( ValueRef const& );
 
+// All mutations done to this range are blindly copied into txnStateStore.
+// Used to create artifically large txnStateStore instances in testing.
+extern const KeyRangeRef testOnlyTxnStateStorePrefixRange;
+
 #endif

fdbserver/ApplyMetadataMutation.h

@@ -182,7 +182,7 @@ static void applyMetadataMutations(UID const& dbgid, Arena &arena, VectorRef<Mut
 					}
 				}
 			} else if( m.param1 == databaseLockedKey || m.param1 == metadataVersionKey || m.param1 == mustContainSystemMutationsKey || m.param1.startsWith(applyMutationsBeginRange.begin) ||
-				m.param1.startsWith(applyMutationsAddPrefixRange.begin) || m.param1.startsWith(applyMutationsRemovePrefixRange.begin) || m.param1.startsWith(tagLocalityListPrefix) || m.param1.startsWith(serverTagHistoryPrefix) ) {
+				m.param1.startsWith(applyMutationsAddPrefixRange.begin) || m.param1.startsWith(applyMutationsRemovePrefixRange.begin) || m.param1.startsWith(tagLocalityListPrefix) || m.param1.startsWith(serverTagHistoryPrefix) || m.param1.startsWith(testOnlyTxnStateStorePrefixRange.begin) ) {
 				if(!initialCommit) txnStateStore->set(KeyValueRef(m.param1, m.param2));
 			}
 			else if (m.param1.startsWith(applyMutationsEndRange.begin)) {

tests/fast/TxnStateStoreCycleTest.txt

@@ -0,0 +1,32 @@
+testTitle=Clogged
+    testName=Cycle
+    transactionsPerSecond=2500.0
+    testDuration=10.0
+    expectedRate=0
+    keyPrefix=\xff/TESTONLYtxnStateStore/
+
+    testName=RandomClogging
+    testDuration=10.0
+
+    testName=Rollback
+    meanDelay=10.0
+    testDuration=10.0
+
+    testName=Attrition
+    machinesToKill=10
+    machinesToLeave=3
+    reboot=true
+    testDuration=10.0
+
+    testName=Attrition
+    machinesToKill=10
+    machinesToLeave=3
+    reboot=true
+    testDuration=10.0
+
+testTitle=Unclogged
+    testName=Cycle
+    transactionsPerSecond=250.0
+    testDuration=10.0
+    expectedRate=0.80
+    keyPrefix=\xff/TESTONLYtxnStateStore/