From b1eed6b5862644fe8fdb8b7d3897fdcf227abe71 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Thu, 15 Dec 2005 16:53:21 +0000
Subject: [PATCH] * Split the database upgrade into multiple transactions to
 prevent   Berkeley DB from running out of locks.

---
 src/libstore/store.cc | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/libstore/store.cc b/src/libstore/store.cc
index 48f09fefe..281ccc4bf 100644
--- a/src/libstore/store.cc
+++ b/src/libstore/store.cc
@@ -1012,6 +1012,8 @@ static void upgradeStore07()
    (and properly spelled) `referrer' table. */
 static void upgradeStore09() 
 {
+    /* !!! we should disallow concurrent upgrades */
+    
     printMsg(lvlError, "upgrading Nix store to new schema (this may take a while)...");
 
     if (!pathExists(nixDBPath + "/referers")) return;
@@ -1024,6 +1026,8 @@ static void upgradeStore09()
 
     Paths referersKeys;
     nixDB.enumTable(txn, dbReferers, referersKeys);
+
+    int n = 0;
     for (Paths::iterator i = referersKeys.begin();
          i != referersKeys.end(); ++i)
     {
@@ -1032,12 +1036,17 @@ static void upgradeStore09()
         for (Paths::iterator j = referers.begin();
              j != referers.end(); ++j)
             nixDB.setString(txn, dbReferrers, addPrefix(*i, *j), "");
+        if (++n % 1000 == 0) {
+            txn.commit();
+            txn.begin(nixDB);
+            cerr << "|";
+        }
         cerr << ".";
     }
 
-    cerr << "\n";
-
     txn.commit();
+    
+    cerr << "\n";
 
     nixDB.closeTable(dbReferers);