merge the brt prefetch changes to the main trunk. closes #1183

git-svn-id: file:///svn/toku/tokudb@9135 c7de825b-a66e-492c-adef-691d508d4ae1

newbrt/brt-internal.h

@@ -233,6 +233,7 @@ struct brt_cursor {
     struct list cursors_link;
     BRT brt;
     BOOL current_in_omt, prev_in_omt;
+    BOOL prefetching;
     DBT key, val;             // The key-value pair that the cursor currently points to
     DBT prevkey, prevval;     // The key-value pair that the cursor pointed to previously.  (E.g., when we do a DB_NEXT)
     int is_temporary_cursor;  // If it is a temporary cursor then use the following skey and sval to return tokudb-managed values in dbts.  Otherwise use the brt's skey and skval.

newbrt/brtdump.c

@@ -236,23 +236,30 @@ split_fields (char *line, char *fields[], int maxfields) {
     return i;
 }
 
+static int
+usage(const char *arg0) {
+    printf("Usage: %s [--nodata] [--interactive] brtfilename\n", arg0);
+    return 1;
+}
+
 int 
 main (int argc, const char *argv[]) {
     const char *arg0 = argv[0];
-    static int interactive = 0;
+    int interactive = 0;
     argc--; argv++;
-    while (argc>1) {
-	if (strcmp(argv[0], "--nodata")==0) {
+    while (argc>0) {
+	if (strcmp(argv[0], "--nodata") == 0) {
 	    dump_data = 0;
         } else if (strcmp(argv[0], "--interactive") == 0) {
             interactive = 1;
-	} else {
-	    printf("Usage: %s [--nodata] brtfilename\n", arg0);
-	    exit(1);
-	}
+        } else if (strcmp(argv[0], "--help") == 0) {
+            return usage(arg0);
+	} else 
+	    break;
 	argc--; argv++;
     }
-    assert(argc==1);
+    if (argc != 1) return usage(arg0);
+
     const char *n = argv[0];
     int f = open(n, O_RDONLY + O_BINARY);  assert(f>=0);
     struct brt_header *h;

newbrt/cachetable.c

@@ -578,6 +578,7 @@ static int cachetable_fetch_pair(CACHETABLE ct, CACHEFILE cf, PAIR p) {
     }
     p->state = CTPAIR_IDLE;
     ctpair_write_unlock(&p->rwlock);
+    if (0) printf("%s:%d %"PRId64" complete\n", __FUNCTION__, __LINE__, key.b);
     return 0;
 }
 
@@ -922,6 +923,7 @@ int toku_cachefile_prefetch(CACHEFILE cf, CACHEKEY key, u_int32_t fullhash,
                             CACHETABLE_FLUSH_CALLBACK flush_callback, 
                             CACHETABLE_FETCH_CALLBACK fetch_callback, 
                             void *extraargs) {
+    if (0) printf("%s:%d %"PRId64"\n", __FUNCTION__, __LINE__, key.b);
     CACHETABLE ct = cf->cachetable;
     cachetable_lock(ct);
     // lookup