[t:3635] [t:3764] [t:3757] [t:3749] merging tokudb.3635+prefetch into...

[t:3635] [t:3764] [t:3757] [t:3749] merging tokudb.3635+prefetch into mainline, pending testing, fixes #3635, #3764, #3757, #3749

git-svn-id: file:///svn/toku/tokudb@33537 c7de825b-a66e-492c-adef-691d508d4ae1

db-benchmark-test/scanscan.c

@@ -138,9 +138,9 @@ static void parse_args (int argc, char *const argv[]) {
     }
     //Prelocking is meaningless without transactions
     if (do_txns==0) {
-        prelockflag=0;
+      //prelockflag=0;
         lock_flag=0;
-        prelock=0;
+        //prelock=0;
     }
 }
 
@@ -294,6 +294,9 @@ static void scanscan_lwc (void) {
 	double prevtime = gettime();
 	DBC *dbc;
 	r = db->cursor(db, tid, &dbc, 0);                           assert(r==0);
+	if(prelock) {
+            r = dbc->c_pre_acquire_range_lock(dbc, db->dbt_neg_infty(), db->dbt_pos_infty()); assert(r==0);
+	}
         u_int32_t f_flags = 0;
         if (prelockflag && (counter || prelock)) {
             f_flags |= lock_flag;

newbrt/brt-internal.h

@@ -89,6 +89,7 @@ add_estimates (struct subtree_estimates *a, struct subtree_estimates *b) {
 enum brtnode_fetch_type {
     brtnode_fetch_none=1, // no partitions needed.  
     brtnode_fetch_subset, // some subset of partitions needed
+    brtnode_fetch_prefetch, // this is part of a prefetch call
     brtnode_fetch_all // every partition is needed
 };
 
@@ -107,6 +108,8 @@ struct brtnode_fetch_extra {
     // parameters needed to find out which child needs to be decompressed (so it can be read)
     brt_search_t* search;
     BRT brt;
+    DBT *range_lock_left_key, *range_lock_right_key;
+    BOOL left_is_neg_infty, right_is_pos_infty;
     // this value will be set during the fetch_callback call by toku_brtnode_fetch_callback or toku_brtnode_pf_req_callback
     // thi callbacks need to evaluate this anyway, so we cache it here so the search code does not reevaluate it
     int child_to_read;
@@ -123,8 +126,14 @@ static inline void fill_bfe_for_full_read(struct brtnode_fetch_extra *bfe, struc
     bfe->h = h;
     bfe->search = NULL;
     bfe->brt = NULL;
+    bfe->range_lock_left_key = NULL;
+    bfe->range_lock_right_key = NULL;
+    bfe->left_is_neg_infty = FALSE;
+    bfe->right_is_pos_infty = FALSE;
     bfe->child_to_read = -1;
-};
+}
+
+static inline void fill_bfe_for_prefetch(struct brtnode_fetch_extra *bfe, struct brt_header *h, BRT brt, BRT_CURSOR c);
 
 //
 // Helper function to fill a brtnode_fetch_extra with data
@@ -136,15 +145,23 @@ static inline void fill_bfe_for_subset_read(
     struct brtnode_fetch_extra *bfe, 
     struct brt_header *h,
     BRT brt,
-    brt_search_t* search
+    brt_search_t* search,
+    DBT *left,
+    DBT *right,
+    BOOL left_is_neg_infty,
+    BOOL right_is_pos_infty
     ) 
 {
     bfe->type = brtnode_fetch_subset;
     bfe->h = h;
     bfe->search = search;
     bfe->brt = brt;
+    bfe->range_lock_left_key = left;
+    bfe->range_lock_right_key = right;
+    bfe->left_is_neg_infty = left_is_neg_infty;
+    bfe->right_is_pos_infty = right_is_pos_infty;
     bfe->child_to_read = -1;
-};
+}
 
 //
 // Helper function to fill a brtnode_fetch_extra with data
@@ -157,8 +174,26 @@ static inline void fill_bfe_for_min_read(struct brtnode_fetch_extra *bfe, struct
     bfe->h = h;
     bfe->search = NULL;
     bfe->brt = NULL;
+    bfe->range_lock_left_key = NULL;
+    bfe->range_lock_right_key = NULL;
+    bfe->left_is_neg_infty = FALSE;
+    bfe->right_is_pos_infty = FALSE;
     bfe->child_to_read = -1;
-};
+}
+
+static inline void destroy_bfe_for_prefetch(struct brtnode_fetch_extra *bfe) {
+    assert(bfe->type == brtnode_fetch_prefetch);
+    if (bfe->range_lock_left_key != NULL) {
+        toku_destroy_dbt(bfe->range_lock_left_key);
+        toku_free(bfe->range_lock_left_key);
+        bfe->range_lock_left_key = NULL;
+    }
+    if (bfe->range_lock_right_key != NULL) {
+        toku_destroy_dbt(bfe->range_lock_right_key);
+        toku_free(bfe->range_lock_right_key);
+        bfe->range_lock_right_key = NULL;
+    }
+}
 
 // data of an available partition of a nonleaf brtnode
 struct brtnode_nonleaf_childinfo {
@@ -526,6 +561,8 @@ struct brt_cursor {
     BOOL current_in_omt;
     BOOL prefetching;
     DBT key, val;             // The key-value pair that the cursor currently points to
+    DBT range_lock_left_key, range_lock_right_key;
+    BOOL left_is_neg_infty, right_is_pos_infty;
     OMTCURSOR omtcursor;
     u_int64_t  root_put_counter; // what was the count on the BRT when we validated the cursor?
     TXNID      oldest_living_xid;// what was the oldest live txnid when we created the cursor?
@@ -535,6 +572,33 @@ struct brt_cursor {
     struct brt_cursor_leaf_info  leaf_info;
 };
 
+// this is in a strange place because it needs the cursor struct to be defined
+static inline void fill_bfe_for_prefetch(struct brtnode_fetch_extra *bfe, struct brt_header *h, BRT brt, BRT_CURSOR c) {
+    bfe->type = brtnode_fetch_prefetch;
+    bfe->h = h;
+    bfe->search = NULL;
+    bfe->brt = brt;
+    {
+        const DBT *left = &c->range_lock_left_key;
+        const DBT *right = &c->range_lock_right_key;
+        if (left->data) {
+            MALLOC(bfe->range_lock_left_key); resource_assert(bfe->range_lock_left_key);
+            toku_fill_dbt(bfe->range_lock_left_key, toku_xmemdup(left->data, left->size), left->size);
+        } else {
+            bfe->range_lock_left_key = NULL;
+        }
+        if (right->data) {
+            MALLOC(bfe->range_lock_right_key); resource_assert(bfe->range_lock_right_key);
+            toku_fill_dbt(bfe->range_lock_right_key, toku_xmemdup(right->data, right->size), right->size);
+        } else {
+            bfe->range_lock_right_key = NULL;
+        }
+    }
+    bfe->left_is_neg_infty = c->left_is_neg_infty;
+    bfe->right_is_pos_infty = c->right_is_pos_infty;
+    bfe->child_to_read = -1;
+}
+
 typedef struct ancestors *ANCESTORS;
 struct ancestors {
     BRTNODE   node;     // This is the root node if next is NULL.
@@ -556,6 +620,11 @@ toku_brt_search_which_child(
 bool 
 toku_bfe_wants_child_available (struct brtnode_fetch_extra* bfe, int childnum);
 
+int
+toku_bfe_leftmost_child_wanted(struct brtnode_fetch_extra *bfe, BRTNODE node);
+int
+toku_bfe_rightmost_child_wanted(struct brtnode_fetch_extra *bfe, BRTNODE node);
+
 // allocate a block number
 // allocate and initialize a brtnode
 // put the brtnode into the cache table

newbrt/brt-serialize.c

@@ -8,6 +8,15 @@
 #include "threadpool.h"
 #include <compress.h>
 
+#if defined(HAVE_CILK)
+#include <cilk/cilk.h>
+#define cilk_worker_count (__cilkrts_get_nworkers())
+#else
+#define cilk_spawn
+#define cilk_sync
+#define cilk_for for
+#define cilk_worker_count 1
+#endif
 
 static BRT_UPGRADE_STATUS_S upgrade_status;  // accountability, used in backwards_x.c
 
@@ -607,6 +616,27 @@ rebalance_brtnode_leaf(BRTNODE node, unsigned int basementnodesize)
     toku_free(new_pivots);
 }
 
+static void
+serialize_and_compress(BRTNODE node, int npartitions, struct sub_block sb[]);
+
+
+// tests are showing that serial insertions are slightly faster 
+// using the pthreads than using CILK. Disabling CILK until we have
+// some evidence that it is faster
+//#ifdef HAVE_CILK
+#if 0
+
+static void
+serialize_and_compress(BRTNODE node, int npartitions, struct sub_block sb[]) {
+#pragma cilk grainsize = 1
+    cilk_for (int i = 0; i < npartitions; i++) {
+        serialize_brtnode_partition(node, i, &sb[i]);
+        compress_brtnode_sub_block(&sb[i]);
+    }
+}
+
+#else
+
 struct serialize_compress_work {
     struct work base;
     BRTNODE node;
@@ -657,6 +687,8 @@ serialize_and_compress(BRTNODE node, int npartitions, struct sub_block sb[]) {
     }
 }
 
+#endif
+
 // Writes out each child to a separate malloc'd buffer, then compresses
 // all of them, and writes the uncompressed header, to bytes_to_write,
 // which is malloc'd.
@@ -677,7 +709,7 @@ toku_serialize_brtnode_to_memory (BRTNODE node,
     // Each partition represents a compressed sub block
     // For internal nodes, a sub block is a message buffer
     // For leaf nodes, a sub block is a basement node
-    struct sub_block sb[npartitions];
+    struct sub_block *MALLOC_N(npartitions, sb);
     struct sub_block sb_node_info;
     for (int i = 0; i < npartitions; i++) {
         sub_block_init(&sb[i]);;
@@ -687,15 +719,7 @@ toku_serialize_brtnode_to_memory (BRTNODE node,
     //
     // First, let's serialize and compress the individual sub blocks
     //
-#if 0
-    // TODO: (Zardosht) cilkify this
-    for (int i = 0; i < npartitions; i++) {
-        serialize_brtnode_partition(node, i, &sb[i]);
-        compress_brtnode_sub_block(&sb[i]);
-    }
-#else
     serialize_and_compress(node, npartitions, sb);
-#endif
 
     //
     // Now lets create a sub-block that has the common node information,
@@ -763,6 +787,7 @@ toku_serialize_brtnode_to_memory (BRTNODE node,
         toku_free(sb[i].uncompressed_ptr);
     }
 
+    toku_free(sb);
     return 0;
 }
 
@@ -1071,7 +1096,7 @@ setup_available_brtnode_partition(BRTNODE node, int i) {
 
 static void
 setup_brtnode_partitions(BRTNODE node, struct brtnode_fetch_extra* bfe) {
-    if (bfe->type == brtnode_fetch_subset) {
+    if (bfe->type == brtnode_fetch_subset && bfe->search != NULL) {
         // we do not take into account prefetching yet
         // as of now, if we need a subset, the only thing
         // we can possibly require is a single basement node
@@ -1085,18 +1110,30 @@ setup_brtnode_partitions(BRTNODE node, struct brtnode_fetch_extra* bfe) {
             bfe->search
             );
     }
+    int lc, rc;
+    if (bfe->type == brtnode_fetch_subset || bfe->type == brtnode_fetch_prefetch) {
+        lc = toku_bfe_leftmost_child_wanted(bfe, node);
+        rc = toku_bfe_rightmost_child_wanted(bfe, node);
+    } else {
+        lc = -1;
+        rc = -1;
+    }
     //
     // setup memory needed for the node
     //
+    //printf("node height %d, blocknum %"PRId64", type %d lc %d rc %d\n", node->height, node->thisnodename.b, bfe->type, lc, rc);
     for (int i = 0; i < node->n_children; i++) {
         BP_INIT_UNTOUCHED_CLOCK(node,i);
-        BP_STATE(node,i) = toku_bfe_wants_child_available(bfe,i) ? PT_AVAIL : PT_COMPRESSED;
+        BP_STATE(node, i) = ((toku_bfe_wants_child_available(bfe, i) || (lc <= i && i <= rc))
+                             ? PT_AVAIL : PT_COMPRESSED);
         BP_WORKDONE(node,i) = 0;
         if (BP_STATE(node,i) == PT_AVAIL) {
+	    //printf(" %d is available\n", i);
             setup_available_brtnode_partition(node, i);
             BP_TOUCH_CLOCK(node,i);
         }
         else if (BP_STATE(node,i) == PT_COMPRESSED) {
+	    //printf(" %d is compressed\n", i);
             set_BSB(node, i, sub_block_creat());
         }
         else {
@@ -1153,6 +1190,25 @@ deserialize_brtnode_partition(
     assert(rb.ndone == rb.size);
 }
 
+static void
+decompress_and_deserialize_worker(struct rbuf curr_rbuf, struct sub_block curr_sb, BRTNODE node, int child)
+{
+    read_and_decompress_sub_block(&curr_rbuf, &curr_sb);
+    // at this point, sb->uncompressed_ptr stores the serialized node partition
+    deserialize_brtnode_partition(&curr_sb, node, child);
+    toku_free(curr_sb.uncompressed_ptr);
+}
+
+static void
+check_and_copy_compressed_sub_block_worker(struct rbuf curr_rbuf, struct sub_block curr_sb, BRTNODE node, int child)
+{
+    read_compressed_sub_block(&curr_rbuf, &curr_sb);
+    SUB_BLOCK bp_sb = BSB(node, child);
+    bp_sb->compressed_size = curr_sb.compressed_size;
+    bp_sb->uncompressed_size = curr_sb.uncompressed_size;
+    bp_sb->compressed_ptr = toku_xmalloc(bp_sb->compressed_size);
+    memcpy(bp_sb->compressed_ptr, curr_sb.compressed_ptr, bp_sb->compressed_size);
+}
 
 //
 // deserializes a brtnode that is in rb (with pointer of rb just past the magic) into a BRTNODE
@@ -1214,14 +1270,13 @@ deserialize_brtnode_from_rbuf(
 
     // now that the node info has been deserialized, we can proceed to deserialize
     // the individual sub blocks
-    assert(bfe->type == brtnode_fetch_none || bfe->type == brtnode_fetch_subset || bfe->type == brtnode_fetch_all);
+    assert(bfe->type == brtnode_fetch_none || bfe->type == brtnode_fetch_subset || bfe->type == brtnode_fetch_all || bfe->type == brtnode_fetch_prefetch);
 
     // setup the memory of the partitions
     // for partitions being decompressed, create either FIFO or basement node
     // for partitions staying compressed, create sub_block
     setup_brtnode_partitions(node,bfe);
 
-    // TODO: (Zardosht) Cilkify this
     for (int i = 0; i < node->n_children; i++) {
         u_int32_t curr_offset = (i==0) ? 0 : BP_OFFSET(node,i-1);
         u_int32_t curr_size = (i==0) ? BP_OFFSET(node,i) : (BP_OFFSET(node,i) - BP_OFFSET(node,i-1));
@@ -1231,9 +1286,6 @@ deserialize_brtnode_from_rbuf(
         struct rbuf curr_rbuf  = {.buf = NULL, .size = 0, .ndone = 0};
         rbuf_init(&curr_rbuf, rb->buf + rb->ndone + curr_offset, curr_size);
 
-        struct sub_block curr_sb;
-	sub_block_init(&curr_sb);
-
         //
         // now we are at the point where we have:
         //  - read the entire compressed node off of disk,
@@ -1247,29 +1299,21 @@ deserialize_brtnode_from_rbuf(
         // form into the node, and set the state of the partition to PT_COMPRESSED
         //
 
+        struct sub_block curr_sb;
+        sub_block_init(&curr_sb);
+
         //  case where we read and decompress the partition
         // deserialize_brtnode_info figures out what the state
         // should be and sets up the memory so that we are ready to use it
         if (BP_STATE(node,i) == PT_AVAIL) {
-            read_and_decompress_sub_block(&curr_rbuf, &curr_sb);
-            // at this point, sb->uncompressed_ptr stores the serialized node partition
-            deserialize_brtnode_partition(&curr_sb, node, i);
-            toku_free(curr_sb.uncompressed_ptr);
+            cilk_spawn decompress_and_deserialize_worker(curr_rbuf, curr_sb, node, i);
         }
         // case where we leave the partition in the compressed state
         else if (BP_STATE(node,i) == PT_COMPRESSED) {
-            read_compressed_sub_block(&curr_rbuf, &curr_sb);
-            SUB_BLOCK bp_sb = BSB(node, i);
-            bp_sb->compressed_size = curr_sb.compressed_size;
-            bp_sb->uncompressed_size = curr_sb.uncompressed_size;
-            bp_sb->compressed_ptr = toku_xmalloc(bp_sb->compressed_size);
-            memcpy(
-                bp_sb->compressed_ptr, 
-                curr_sb.compressed_ptr, 
-                bp_sb->compressed_size
-                );
+            cilk_spawn check_and_copy_compressed_sub_block_worker(curr_rbuf, curr_sb, node, i);
         }
     }
+    cilk_sync;
     *brtnode = node;
     r = 0;
 cleanup:

newbrt/brt.h

@@ -192,6 +192,7 @@ typedef struct brt_cursor *BRT_CURSOR;
 int toku_brt_cursor (BRT, BRT_CURSOR*, TOKUTXN, BOOL)  __attribute__ ((warn_unused_result));
 void toku_brt_cursor_set_leaf_mode(BRT_CURSOR);
 int toku_brt_cursor_is_leaf_mode(BRT_CURSOR);
+void toku_brt_cursor_set_range_lock(BRT_CURSOR, const DBT *, const DBT *, BOOL, BOOL);
 
 // get is deprecated in favor of the individual functions below
 int toku_brt_cursor_get (BRT_CURSOR cursor, DBT *key, BRT_GET_CALLBACK_FUNCTION getf, void *getf_v, int get_flags)  __attribute__ ((warn_unused_result));

newbrt/cachetable.c

@@ -24,6 +24,7 @@
 // use worker threads 0->no 1->yes
 static void cachetable_writer(WORKITEM);
 static void cachetable_reader(WORKITEM);
+static void cachetable_partial_reader(WORKITEM);
 
 #define TRACE_CACHETABLE 0
 #if TRACE_CACHETABLE
@@ -1466,6 +1467,44 @@ write_pair_for_checkpoint (CACHETABLE ct, PAIR p, BOOL write_if_dirty)
     }
 }
 
+static void
+do_partial_fetch(CACHETABLE ct, CACHEFILE cachefile, PAIR p, CACHETABLE_PARTIAL_FETCH_CALLBACK pf_callback, void *read_extraargs)
+{
+    long old_size = p->size;
+    long size = 0;
+    //
+    // The reason we have this assert is a sanity check
+    // to make sure that it is ok to set the 
+    // state of the pair to CTPAIR_READING.
+    // 
+    // As of this writing, the checkpoint code assumes
+    // that every pair that is in the CTPAIR_READING state
+    // is not dirty. Because we require dirty nodes to be
+    // fully in memory, we should never have a dirty node 
+    // require a partial fetch. So, just to be sure that 
+    // we can set the pair to CTPAIR_READING, we assert
+    // that the pair is not dirty
+    //
+    assert(!p->dirty);
+    p->state = CTPAIR_READING;
+
+    rwlock_prefer_read_lock(&cachefile->fdlock, ct->mutex);
+    cachetable_unlock(ct);
+    int r = pf_callback(p->value, read_extraargs, cachefile->fd, &size);
+    lazy_assert_zero(r);
+    cachetable_lock(ct);
+    rwlock_read_unlock(&cachefile->fdlock);
+    p->size = size;
+    ct->size_current += size;
+    ct->size_current -= old_size;
+    p->state = CTPAIR_IDLE;
+    if (p->cq) {
+        workitem_init(&p->asyncwork, NULL, p);
+        workqueue_enq(p->cq, &p->asyncwork, 1);
+    }
+    rwlock_write_unlock(&p->rwlock);
+}
+
 // for debugging
 // valid only if this function is called only by a single thread
 static u_int64_t get_and_pin_footprint = 0;
@@ -1571,21 +1610,10 @@ int toku_cachetable_get_and_pin (
                     cachetable_waittime += get_tnow() - t0;
                 }
                 t0 = get_tnow();
-                long old_size = p->size;
-                long size = 0;
-                rwlock_prefer_read_lock(&cachefile->fdlock, ct->mutex);
-                cachetable_unlock(ct);
-                int r = pf_callback(p->value, read_extraargs, cachefile->fd, &size);
-                cachetable_lock(ct);
-                rwlock_read_unlock(&cachefile->fdlock);
-                p->size = size;
-                // set the state of the pair back
-                p->state = CTPAIR_IDLE;
-                ct->size_current += size;
-                ct->size_current -= old_size;
-                lazy_assert_zero(r);                
+
+                do_partial_fetch(ct, cachefile, p, pf_callback, read_extraargs);
+
                 cachetable_waittime += get_tnow() - t0;
-                rwlock_write_unlock(&p->rwlock);
                 rwlock_read_lock(&p->rwlock, ct->mutex);
             }
 
@@ -1917,10 +1945,11 @@ int toku_cachetable_get_and_pin_nonblocking (
                         run_unlockers(unlockers); // The contract says the unlockers are run with the ct lock being held.
                         if (ct->ydb_unlock_callback) ct->ydb_unlock_callback();
                         // Now wait for the I/O to occur.
-                        rwlock_prefer_read_lock(&cf->fdlock, ct->mutex);
-                        long old_size = p->size;
-                        long size = 0;
+
+                        do_partial_fetch(ct, cf, p, pf_callback, read_extraargs);
+
                         cachetable_unlock(ct);
+<<<<<<< .working
                         int r = pf_callback(p->value, read_extraargs, cf->fd, &size);
                         lazy_assert_zero(r);
                         cachetable_lock(ct);
@@ -1932,6 +1961,8 @@ int toku_cachetable_get_and_pin_nonblocking (
                         ct->size_current -= old_size;
                         rwlock_write_unlock(&p->rwlock);
                         cachetable_unlock(ct);
+=======
+>>>>>>> .merge-right.r33536
                         if (ct->ydb_lock_callback) ct->ydb_lock_callback();
                         return TOKUDB_TRY_AGAIN;
                     }
@@ -1982,17 +2013,21 @@ struct cachefile_prefetch_args {
     void* read_extraargs;
 };
 
-//
-// PREFETCHING DOES NOT WORK IN MAXWELL AS OF NOW!
-//
+struct cachefile_partial_prefetch_args {
+    PAIR p;
+    CACHETABLE_PARTIAL_FETCH_CALLBACK pf_callback;
+    void *read_extraargs;
+};
+
 int toku_cachefile_prefetch(CACHEFILE cf, CACHEKEY key, u_int32_t fullhash,
                             CACHETABLE_FLUSH_CALLBACK flush_callback,
                             CACHETABLE_FETCH_CALLBACK fetch_callback,
                             CACHETABLE_PARTIAL_EVICTION_CALLBACK pe_callback,
-                            CACHETABLE_PARTIAL_FETCH_REQUIRED_CALLBACK pf_req_callback  __attribute__((unused)),
-                            CACHETABLE_PARTIAL_FETCH_CALLBACK pf_callback  __attribute__((unused)),
+                            CACHETABLE_PARTIAL_FETCH_REQUIRED_CALLBACK pf_req_callback,
+                            CACHETABLE_PARTIAL_FETCH_CALLBACK pf_callback,
                             void *read_extraargs,
-                            void *write_extraargs)
+                            void *write_extraargs,
+                            BOOL *doing_prefetch)
 // Effect: See the documentation for this function in cachetable.h
 {
     // TODO: Fix prefetching, as part of ticket 3635
@@ -2005,6 +2040,9 @@ int toku_cachefile_prefetch(CACHEFILE cf, CACHEKEY key, u_int32_t fullhash,
     // It may be another callback. That is way too many callbacks that are being used
     // Fixing this in a clean, simple way requires some thought.
     if (0) printf("%s:%d %"PRId64"\n", __FUNCTION__, __LINE__, key.b);
+    if (doing_prefetch) {
+        *doing_prefetch = FALSE;
+    }
     CACHETABLE ct = cf->cachetable;
     cachetable_lock(ct);
     // lookup
@@ -2023,12 +2061,33 @@ int toku_cachefile_prefetch(CACHEFILE cf, CACHEKEY key, u_int32_t fullhash,
         p = cachetable_insert_at(ct, cf, key, zero_value, CTPAIR_READING, fullhash, zero_size, flush_callback, pe_callback, write_extraargs, CACHETABLE_CLEAN);
         assert(p);
         rwlock_write_lock(&p->rwlock, ct->mutex);
-        struct cachefile_prefetch_args *cpargs = toku_xmalloc(sizeof(struct cachefile_prefetch_args));
+        struct cachefile_prefetch_args *MALLOC(cpargs);
         cpargs->p = p;
         cpargs->fetch_callback = fetch_callback;
         cpargs->read_extraargs = read_extraargs;
         workitem_init(&p->asyncwork, cachetable_reader, cpargs);
         workqueue_enq(&ct->wq, &p->asyncwork, 0);
+        if (doing_prefetch) {
+            *doing_prefetch = TRUE;
+        }
+    } else if (p->state == CTPAIR_IDLE && (rwlock_users(&p->rwlock)==0)) {
+        // nobody else is using the node, so we should go ahead and prefetch
+        rwlock_read_lock(&p->rwlock, ct->mutex);
+        BOOL partial_fetch_required = pf_req_callback(p->value, read_extraargs);
+        rwlock_read_unlock(&p->rwlock);
+
+        if (partial_fetch_required) {
+            rwlock_write_lock(&p->rwlock, ct->mutex);
+            struct cachefile_partial_prefetch_args *MALLOC(cpargs);
+            cpargs->p = p;
+            cpargs->pf_callback = pf_callback;
+            cpargs->read_extraargs = read_extraargs;
+            workitem_init(&p->asyncwork, cachetable_partial_reader, cpargs);
+            workqueue_enq(&ct->wq, &p->asyncwork, 0);
+            if (doing_prefetch) {
+                *doing_prefetch = TRUE;
+            }
+        }
     }
     cachetable_unlock(ct);
     return 0;
@@ -2701,6 +2760,15 @@ static void cachetable_reader(WORKITEM wi) {
     toku_free(cpargs);
 }
 
+static void cachetable_partial_reader(WORKITEM wi) {
+    struct cachefile_partial_prefetch_args *cpargs = workitem_arg(wi);
+    CACHETABLE ct = cpargs->p->cachefile->cachetable;
+    cachetable_lock(ct);
+    do_partial_fetch(ct, cpargs->p->cachefile, cpargs->p, cpargs->pf_callback, cpargs->read_extraargs);
+    cachetable_unlock(ct);
+    toku_free(cpargs);
+}
+
 
 // debug functions
 

newbrt/cachetable.h

@@ -269,10 +269,11 @@ int toku_cachefile_prefetch(CACHEFILE cf, CACHEKEY key, u_int32_t fullhash,
                             CACHETABLE_FLUSH_CALLBACK flush_callback, 
                             CACHETABLE_FETCH_CALLBACK fetch_callback, 
                             CACHETABLE_PARTIAL_EVICTION_CALLBACK pe_callback,
-                            CACHETABLE_PARTIAL_FETCH_REQUIRED_CALLBACK pf_req_callback  __attribute__((unused)),
-                            CACHETABLE_PARTIAL_FETCH_CALLBACK pf_callback  __attribute__((unused)),
+                            CACHETABLE_PARTIAL_FETCH_REQUIRED_CALLBACK pf_req_callback,
+                            CACHETABLE_PARTIAL_FETCH_CALLBACK pf_callback,
                             void *read_extraargs, 
-                            void *write_extraargs);
+                            void *write_extraargs,
+                            BOOL *doing_prefetch);
 // Effect: Prefetch a memory object for a given key into the cachetable
 // Precondition: The cachetable mutex is NOT held.
 // Postcondition: The cachetable mutex is NOT held.

newbrt/rollback.c

@@ -775,6 +775,7 @@ toku_maybe_prefetch_older_rollback_log(TOKUTXN txn, ROLLBACK_LOG_NODE log) {
         uint32_t hash = log->older_hash;
         CACHEFILE cf = txn->logger->rollback_cachefile;
         struct brt_header *h = toku_cachefile_get_userdata(cf);
+        BOOL doing_prefetch = FALSE;
         r = toku_cachefile_prefetch(cf, name, hash,
                                     toku_rollback_flush_callback,
                                     toku_rollback_fetch_callback,
@@ -782,7 +783,8 @@ toku_maybe_prefetch_older_rollback_log(TOKUTXN txn, ROLLBACK_LOG_NODE log) {
                                     toku_brtnode_pf_req_callback,
                                     toku_brtnode_pf_callback,
                                     h,
-                                    h);
+                                    h,
+                                    &doing_prefetch);
         assert(r==0);
     }
     return r;

newbrt/tests/cachetable-prefetch-checkpoint-test.c

@@ -76,7 +76,7 @@ static void cachetable_prefetch_checkpoint_test(int n, enum cachetable_dirty dir
     {
         CACHEKEY key = make_blocknum(n+1);
         u_int32_t fullhash = toku_cachetable_hash(f1, key);
-        r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0);
+        r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0, NULL);
         toku_cachetable_verify(ct);
     }
 

newbrt/tests/cachetable-prefetch-close-fail-test.c

@@ -76,7 +76,7 @@ static void cachetable_prefetch_maybegetandpin_test (void) {
     // prefetch block 0. this will take 10 seconds.
     CACHEKEY key = make_blocknum(0);
     u_int32_t fullhash = toku_cachetable_hash(f1, make_blocknum(0));
-    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0);
+    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0, NULL);
     toku_cachetable_verify(ct);
 
     // close with the prefetch in progress. the close should block until

newbrt/tests/cachetable-prefetch-close-leak-test.c

@@ -77,7 +77,7 @@ static void cachetable_prefetch_close_leak_test (void) {
     // prefetch block 0. this will take 10 seconds.
     CACHEKEY key = make_blocknum(0);
     u_int32_t fullhash = toku_cachetable_hash(f1, make_blocknum(0));
-    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0);
+    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0, NULL);
     toku_cachetable_verify(ct);
 
     // close with the prefetch in progress. the close should block until

newbrt/tests/cachetable-prefetch-close-test.c

@@ -77,7 +77,7 @@ static void cachetable_prefetch_maybegetandpin_test (void) {
     // prefetch block 0. this will take 10 seconds.
     CACHEKEY key = make_blocknum(0);
     u_int32_t fullhash = toku_cachetable_hash(f1, make_blocknum(0));
-    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0);
+    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0, NULL);
     toku_cachetable_verify(ct);
 
     // close with the prefetch in progress. the close should block until

newbrt/tests/cachetable-prefetch-flowcontrol-test.c

@@ -92,7 +92,7 @@ static void cachetable_prefetch_flowcontrol_test (int cachetable_size_limit) {
     for (i=0; i<cachetable_size_limit; i++) {
         CACHEKEY key = make_blocknum(i);
         u_int32_t fullhash = toku_cachetable_hash(f1, key);
-        r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0);
+        r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0, NULL);
         toku_cachetable_verify(ct);
     }
 
@@ -103,7 +103,7 @@ static void cachetable_prefetch_flowcontrol_test (int cachetable_size_limit) {
     for (i=i; i<2*cachetable_size_limit; i++) {
         CACHEKEY key = make_blocknum(i);
         u_int32_t fullhash = toku_cachetable_hash(f1, key);
-        r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0);
+        r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0, NULL);
         toku_cachetable_verify(ct);
 	// sleep(1);
     }

newbrt/tests/cachetable-prefetch-getandpin-fail-test.c

@@ -81,7 +81,7 @@ static void cachetable_prefetch_maybegetandpin_test (void) {
     // prefetch block 0. this will take 10 seconds.
     CACHEKEY key = make_blocknum(0);
     u_int32_t fullhash = toku_cachetable_hash(f1, make_blocknum(0));
-    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0);
+    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0, NULL);
     toku_cachetable_verify(ct);
 
     // verify that get_and_pin waits while the prefetch is in progress

newbrt/tests/cachetable-prefetch-getandpin-test.c

@@ -82,7 +82,7 @@ static void cachetable_prefetch_maybegetandpin_test (void) {
     // prefetch block 0. this will take 10 seconds.
     CACHEKEY key = make_blocknum(0);
     u_int32_t fullhash = toku_cachetable_hash(f1, make_blocknum(0));
-    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0);
+    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0, NULL);
     toku_cachetable_verify(ct);
 
     // verify that get_and_pin waits while the prefetch is in progress

newbrt/tests/cachetable-prefetch-maybegetandpin-test.c

@@ -73,7 +73,7 @@ static void cachetable_prefetch_maybegetandpin_test (void) {
     // prefetch block 0. this will take 10 seconds.
     CACHEKEY key = make_blocknum(0);
     u_int32_t fullhash = toku_cachetable_hash(f1, make_blocknum(0));
-    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0);
+    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0, NULL);
     toku_cachetable_verify(ct);
 
     // verify that maybe_get_and_pin returns an error while the prefetch is in progress

newbrt/tests/cachetable-prefetch2-test.c

@@ -77,11 +77,11 @@ static void cachetable_prefetch_maybegetandpin_test (void) {
     // prefetch block 0. this will take 10 seconds.
     CACHEKEY key = make_blocknum(0);
     u_int32_t fullhash = toku_cachetable_hash(f1, make_blocknum(0));
-    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0);
+    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0, NULL);
     toku_cachetable_verify(ct);
 
     // prefetch again. this should do nothing.
-    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0);
+    r = toku_cachefile_prefetch(f1, key, fullhash, flush, fetch, pe_callback, pf_req_callback, pf_callback, 0, 0, NULL);
     toku_cachetable_verify(ct);
 
     // verify that maybe_get_and_pin returns an error while the prefetch is in progress

src/ydb.c

@@ -5502,8 +5502,11 @@ toku_c_pre_acquire_range_lock(DBC *dbc, const DBT *key_left, const DBT *key_righ
     DB *db = dbc->dbp;
     DB_TXN *txn = dbc_struct_i(dbc)->txn;
     HANDLE_PANICKED_DB(db);
+    toku_brt_cursor_set_range_lock(dbc_struct_i(dbc)->c, key_left, key_right,
+                                   (key_left == toku_lt_neg_infinity),
+                                   (key_right == toku_lt_infinity));
     if (!db->i->lt || !txn)
-        return EINVAL;
+        return 0;
     //READ_UNCOMMITTED and READ_COMMITTED transactions do not need read locks.
     if (!dbc_struct_i(dbc)->rmw && dbc_struct_i(dbc)->iso != TOKU_ISO_SERIALIZABLE)
         return 0;
@@ -5519,7 +5522,7 @@ toku_c_pre_acquire_range_lock(DBC *dbc, const DBT *key_left, const DBT *key_righ
 int 
 toku_db_pre_acquire_table_lock(DB *db, DB_TXN *txn, BOOL just_lock) {
     HANDLE_PANICKED_DB(db);
-    if (!db->i->lt || !txn) return EINVAL;
+    if (!db->i->lt || !txn) return 0;
 
     int r;