Store fewer orphan tx by default, add -maxorphantx option

There is no reason to store thousands of orphan transactions;
normally an orphan's parents will either be broadcast or
mined reasonably quickly.

This pull drops the maximum number of orphans from 10,000 down
to 100, and adds a command-line option (-maxorphantx) that is
just like -maxorphanblocks to override the default.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/main.cpp b/src/main.cpp
index 6581b7d87a..d1726904b6 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3819,7 +3819,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
             AddOrphanTx(tx, pfrom->GetId());
 
             // DoS prevention: do not allow mapOrphanTransactions to grow unbounded
-            unsigned int nEvicted = LimitOrphanTxSize(MAX_ORPHAN_TRANSACTIONS);
+            unsigned int nMaxOrphanTx = (unsigned int)std::max((int64_t)0, GetArg("-maxorphantx", DEFAULT_MAX_ORPHAN_TRANSACTIONS));
+            unsigned int nEvicted = LimitOrphanTxSize(nMaxOrphanTx);
             if (nEvicted > 0)
                 LogPrint("mempool", "mapOrphan overflow, removed %u tx\n", nEvicted);
         }