Addresses #1510 Added some breadcrumbs to checkpoint function,

may be useful for debugging.  In any case, they're harmless.

git-svn-id: file:///svn/toku/tokudb@11410 c7de825b-a66e-492c-adef-691d508d4ae1

newbrt/checkpoint.c

@@ -52,6 +52,13 @@
 #include "cachetable.h"
 #include "checkpoint.h"
 
+// breadcrumbs for debugging
+static u_int64_t breadcrumb0 = 0;
+static u_int64_t breadcrumb1 = 0;
+static u_int64_t breadcrumb2 = 0;
+static u_int64_t breadcrumb3 = 0;
+static u_int64_t breadcrumb4 = 0;
+
 static toku_pthread_rwlock_t checkpoint_safe_lock;
 static toku_pthread_rwlock_t multi_operation_lock;
 
@@ -164,23 +171,28 @@ int
 toku_checkpoint(CACHETABLE ct, TOKULOGGER logger, char **error_string, void (*callback_f)(void*), void * extra) {
     int r;
 
+    breadcrumb0++;
     assert(initialized);
     multi_operation_checkpoint_lock();
     checkpoint_safe_checkpoint_lock();
     ydb_lock();
-
+    
+    breadcrumb1++;
     r = toku_cachetable_begin_checkpoint(ct, logger);
 
     multi_operation_checkpoint_unlock();
     ydb_unlock();
 
+    breadcrumb2++;
     if (r==0) {
 	if (callback_f) 
 	    callback_f(extra);      // callback is called with checkpoint_safe_lock still held
 	r = toku_cachetable_end_checkpoint(ct, logger, error_string);
     }
 
+    breadcrumb3++;
     checkpoint_safe_checkpoint_unlock();
-    
+    breadcrumb4++;
+
     return r;
 }