Lower maximum size for free transaction creation

Changes the maximum size of a free transaction that will be created
from 10,000 bytes to 1,000 bytes.

The idea behind this change is to make the free transaction area
available to a greater number of people; with the default 27K-per-block,
just three very-large very-high-priority transactions could fill the space.

1 files changed, 8 insertions, 13 deletions

diff --git a/src/main.cpp b/src/main.cpp
index 52e89acc26..9c7eece56d 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -608,19 +608,14 @@ int64 CTransaction::GetMinFee(unsigned int nBlockSize, bool fAllowFree,
 
     if (fAllowFree)
     {
-        if (nBlockSize == 1)
-        {
-            // Transactions under 10K are free
-            // (about 4500 BTC if made of 50 BTC inputs)
-            if (nBytes < 10000)
-                nMinFee = 0;
-        }
-        else
-        {
-            // Free transaction area
-            if (nNewBlockSize < DEFAULT_BLOCK_PRIORITY_SIZE)
-                nMinFee = 0;
-        }
+        // There is a free transaction area in blocks created by most miners,
+        // * If we are relaying we allow transactions up to DEFAULT_BLOCK_PRIORITY_SIZE - 1000
+        //   to be considered to fall into this category. We don't want to encourage sending
+        //   multiple transactions instead of one big transaction to avoid fees.
+        // * If we are creating a transaction we allow transactions up to 1,000 bytes
+        //   to be considered safe and assume they can likely make it into this section.
+        if (nBytes < (mode == GMF_SEND ? 1000 : (DEFAULT_BLOCK_PRIORITY_SIZE - 1000)))
+            nMinFee = 0;
     }
 
     // This code can be removed after enough miners have upgraded to version 0.9.