dur

db/dur.cpp

@@ -22,7 +22,7 @@
      PREPLOGBUFFER 
        we will build an output buffer ourself and then use O_DIRECT
        we could be in read lock for this
-       for very large objects write directly to redo log in situ?  will be faster.
+       for very large objects write directly to redo log in situ?
      WRITETOREDOLOG 
        we could be unlocked (the main db lock that is...) for this, with sufficient care, but there is some complexity
          have to handle falling behind which would use too much ram (going back into a read lock would suffice to stop that).
@@ -58,8 +58,8 @@ namespace mongo {
         struct WriteIntent { 
             WriteIntent() : p(0) { }
             WriteIntent(void *a, unsigned b) : p(a), len(b) { }
-            void *p;
-            unsigned len;
+            void *p; // where we will write
+            unsigned len; // up to this len
         };
 
         /* try to remember things we have already marked for journalling.  false negatives are ok if infrequent - 
@@ -72,19 +72,24 @@ namespace mongo {
         public:
             Already() { reset(); }
             void reset() { memset(this, 0, sizeof(*this)); }
+
+            /* see if we have Already recorded/indicated our write intent for this region of memory.
+               @return true if already indicated.
+            */
             bool checkAndSet(const WriteIntent& w) {
-                mongoutils::hash(123);
                 unsigned x = mongoutils::hashPointer(w.p);
-                WriteIntent& n = nodes[x % N];
-                if( n.p != w.p || n.len < w.len ) {
-                    n = w;
+                WriteIntent& nd = nodes[x % N];
+                if( nd.p != w.p || nd.len < w.len ) {
+                    nd = w;
                     return false;
                 }
-                return true; // already done
+                return true;
             }
         };
 
         static Already<127> alreadyNoted;
+
+        /* our record of pending/uncommitted write intents */
         static vector<WriteIntent> writes;
 
         void* writingPtr(void *x, size_t len) { 
@@ -100,6 +105,13 @@ namespace mongo {
             return x;
         }
 
+        void durThread() { 
+        }
+
+        void startup() {
+            boost::thread t(durThread);
+        }
+
     } // namespace dur
 
 } // namespace mongo

db/dur.h

@@ -10,6 +10,7 @@ namespace mongo {
     namespace dur { 
 
 #if !defined(_DURABLE)
+        inline void startup() { }
         inline void* writingPtr(void *x, size_t len) { return x; }
         inline DiskLoc& writingDiskLoc(DiskLoc& d) { return d; }
         inline int& writingInt(int& d) { return d; }
@@ -18,6 +19,9 @@ namespace mongo {
         template <typename T> inline T* writingNoLog(T *x) { return x; }
 #else
 
+        /** call during startup so durability module can initialize */
+        void startup();
+
         /** Declarations of write intent.
             
             Use these methods to declare "i'm about to write to x and it should be logged for redo." 
@@ -44,12 +48,13 @@ namespace mongo {
         }
 
         /** declare our intent to write, but it doesn't have to be journaled, as this write is 
-            something 'unimportant'.
+            something 'unimportant'.  depending on our implementation, we may or may not be able 
+            to take advantage of this versus doing the normal work we do.
         */
         template <typename T> 
         inline 
         T* writingNoLog(T *x) { 
-            log() << "todo dur nolog not yet optimized" << endl;
+            DEV RARELY log() << "todo dur nolog not yet optimized" << endl;
             return (T*) writingPtr(x, sizeof(T));
         }
 

db/dur_journal.cpp

@@ -1,5 +1,5 @@
-// @file dur_journal.cpp
-
+// @file dur_journal.cpp
+
 /**
 *    Copyright (C) 2010 10gen Inc.
 *
@@ -37,7 +37,7 @@ namespace mongo {
         /* temp - this will become more elaborate and probably a class. */
 
 
-        /** call at init.  uasserts on failure.  if fails, you likely want to terminate. */
+        /** call at init.  uasserts on failure.  if fails, you likely want to terminate. */
         void openJournal() { 
 
         }

db/dur_journal.h

@@ -1,5 +1,5 @@
-// @file dur_journal.h
-
+// @file dur_journal.h
+
 /**
 *    Copyright (C) 2010 10gen Inc.
 *
@@ -21,7 +21,7 @@
 namespace mongo {
     namespace dur {
 
-        /** call at init.  uasserts on failure.  if fails, you likely want to terminate. */
+        /** call at init.  uasserts on failure.  if fails, you likely want to terminate. */
         void openJournal();
 
     }

dbtests/dbtests.cpp

@@ -1,4 +1,4 @@
-// dbtests.cpp : Runs db unit tests.
+// #file dbtests.cpp : Runs db unit tests.
 //
 
 /**
@@ -18,11 +18,9 @@
  */
 
 #include "pch.h"
-
 #include "dbtests.h"
 
 int main( int argc, char** argv ) {
     static StaticObserver StaticObserver;
     return Suite::run(argc, argv, "/tmp/unittest");
 }
-

dbtests/framework.cpp

@@ -25,6 +25,7 @@
 
 #include "framework.h"
 #include "../util/file_allocator.h"
+#include "../db/dur.h"
 
 #ifndef _WIN32
 #include <cxxabi.h>
@@ -250,6 +251,8 @@ namespace mongo {
                 filter = params["filter"].as<string>();
             }
 
+            dur::startup();
+
             int ret = run(suites,filter);
 
 #if !defined(_WIN32) && !defined(__sunos__)