Increase maximum orphan size to 100,000 bytes.

Although this increases node memory usage in the worst case by perhaps
 30MB, the current behavior causes severe issues with dependent tx relay.

src/main.cpp

@@ -633,10 +633,10 @@ bool AddOrphanTx(const CTransaction& tx, NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(c
     // large transaction with a missing parent then we assume
     // it will rebroadcast it later, after the parent transaction(s)
     // have been mined or received.
-    // 10,000 orphans, each of which is at most 5,000 bytes big is
-    // at most 500 megabytes of orphans:
+    // 100 orphans, each of which is at most 99,999 bytes big is
+    // at most 10 megabytes of orphans and somewhat more byprev index (in the worst case):
     unsigned int sz = tx.GetSerializeSize(SER_NETWORK, CTransaction::CURRENT_VERSION);
-    if (sz > 5000)
+    if (sz >= MAX_STANDARD_TX_SIZE)
     {
         LogPrint("mempool", "ignoring large orphan tx (size: %u, hash: %s)\n", sz, hash.ToString());
         return false;

src/test/DoS_tests.cpp

@@ -162,7 +162,7 @@ BOOST_AUTO_TEST_CASE(DoS_mapOrphans)
         tx.vout.resize(1);
         tx.vout[0].nValue = 1*CENT;
         tx.vout[0].scriptPubKey = GetScriptForDestination(key.GetPubKey().GetID());
-        tx.vin.resize(500);
+        tx.vin.resize(2777);
         for (unsigned int j = 0; j < tx.vin.size(); j++)
         {
             tx.vin[j].prevout.n = j;