Addresses #1963, #1866 refs[t:1963] refs[t:1866] Minor optimizations to...

Addresses #1963, #1866 refs[t:1963] refs[t:1866] Minor optimizations to maybe_get_and_pin_clean, associate with shortcut query

git-svn-id: file:///svn/toku/tokudb@14169 c7de825b-a66e-492c-adef-691d508d4ae1

newbrt/brt.c

@@ -3946,15 +3946,17 @@ brt_cursor_shortcut (BRT_CURSOR cursor, int direction, u_int32_t limit, BRT_GET_
 #if TOKU_MULTIPLE_MAIN_THREADS
 static int
 brt_cursor_maybe_get_and_pin_leaf(BRT_CURSOR brtcursor, BRTNODE* leafp) {
-    int r = toku_cachetable_maybe_get_and_pin(brtcursor->brt->cf,
-                                              brtcursor->leaf_info.blocknumber,
-                                              brtcursor->leaf_info.fullhash,
-                                              &brtcursor->leaf_info.node);
+    void *leafv;
+    int r = toku_cachetable_maybe_get_and_pin_clean(brtcursor->brt->cf,
+                                                    brtcursor->leaf_info.blocknumber,
+                                                    brtcursor->leaf_info.fullhash,
+                                                   &leafv);
+    assert(r==0);
     if (r == 0) {
-	BRTNODE leaf = brtcursor->leaf_info.node;
-	assert(leaf->height == 0);	// verify that returned node is leaf...
-	assert(leaf->u.l.buffer == toku_omt_cursor_get_omt(brtcursor->omtcursor));  // ... and has right omt
-	*leafp = leaf;
+	brtcursor->leaf_info.node = leafv;
+	assert(brtcursor->leaf_info.node->height == 0);	// verify that returned node is leaf...
+	assert(brtcursor->leaf_info.node->u.l.buffer == toku_omt_cursor_get_omt(brtcursor->omtcursor));  // ... and has right omt
+	*leafp = brtcursor->leaf_info.node;
     }
     return r;
 }

newbrt/cachetable.c

@@ -1148,7 +1148,7 @@ int toku_cachetable_maybe_get_and_pin (CACHEFILE cachefile, CACHEKEY key, u_int3
     for (p=ct->table[fullhash&(ct->table_size-1)]; p; p=p->hash_chain) {
 	count++;
 	if (p->key.b==key.b && p->cachefile==cachefile) {
-            if (p->state == CTPAIR_IDLE && //If not idle, will require a stall and/or will be clean once it is idle
+            if (p->state == CTPAIR_IDLE && //If not idle, will require a stall and/or will be clean once it is idle, or might be GONE once not idle
                 !p->checkpoint_pending &&  //If checkpoint pending, we would need to first write it, which would make it clean
                 p->dirty &&
                 rwlock_try_prefer_read_lock(&p->rwlock, ct->mutex) == 0 //Grab read lock.  If any stall would be necessary that means it would be clean AFTER the stall, so don't even try to stall
@@ -1166,6 +1166,9 @@ int toku_cachetable_maybe_get_and_pin (CACHEFILE cachefile, CACHEKEY key, u_int3
     return r;
 }
 
+//Used by shortcut query path.
+//Same as toku_cachetable_maybe_get_and_pin except that we don't care if the node is clean or dirty (return the node regardless).
+//All other conditions remain the same.
 int toku_cachetable_maybe_get_and_pin_clean (CACHEFILE cachefile, CACHEKEY key, u_int32_t fullhash, void**value) {
     CACHETABLE ct = cachefile->cachetable;
     PAIR p;
@@ -1174,20 +1177,19 @@ int toku_cachetable_maybe_get_and_pin_clean (CACHEFILE cachefile, CACHEKEY key,
     cachetable_lock(ct);
     for (p=ct->table[fullhash&(ct->table_size-1)]; p; p=p->hash_chain) {
 	count++;
-	if (p->key.b==key.b && p->cachefile==cachefile && p->state == CTPAIR_IDLE) {
-
-	    if (p->checkpoint_pending) {
-		goto finish;
-	    }
-	    *value = p->value;
-	    rwlock_read_lock(&p->rwlock, ct->mutex);
-	    lru_touch(ct,p);
-            r = 0;
-	    //printf("%s:%d cachetable_maybe_get_and_pin(%lld)--> %p\n", __FILE__, __LINE__, key, *value);
+	if (p->key.b==key.b && p->cachefile==cachefile) {
+            if (p->state == CTPAIR_IDLE && //If not idle, will require a stall and/or might be GONE once not idle
+                !p->checkpoint_pending &&  //If checkpoint pending, we would need to first write it, which would make it clean (if the pin would be used for writes.  If would be used for read-only we could return it, but that would increase complexity)
+                rwlock_try_prefer_read_lock(&p->rwlock, ct->mutex) == 0 //Grab read lock only if no stall required
+            ) {
+                *value = p->value;
+                lru_touch(ct,p);
+                r = 0;
+                //printf("%s:%d cachetable_maybe_get_and_pin_clean(%lld)--> %p\n", __FILE__, __LINE__, key, *value);
+            }
             break;
 	}
     }
- finish:
     note_hash_count(count);
     cachetable_unlock(ct);
     return r;