diff --git a/memcached.c b/memcached.c
index c7b65f4d7..8d919e768 100644
--- a/memcached.c
+++ b/memcached.c
@@ -528,6 +528,17 @@ static bool conn_reset_buffersize(conn *c)
         }
     }
 
+    if (c->rlsize != RITEM_LIST_INITIAL) {
+        void *ptr = malloc(sizeof(struct iovec) * RITEM_LIST_INITIAL);
+        if (ptr != NULL) {
+            free(c->rlist);
+            c->rlist = ptr;
+            c->rlsize = RITEM_LIST_INITIAL;
+        } else {
+            ret = false;
+        }
+    }
+
     return ret;
 }
 
@@ -555,6 +566,7 @@ static int conn_constructor(void *buffer, void *unused1, int unused2)
         free(c->suffixlist);
         free(c->iov);
         free(c->msglist);
+        free(c->rlist);
         mc_logger->log(EXTENSION_LOG_WARNING, NULL,
                        "Failed to allocate buffers for connection\n");
         return 1;
@@ -583,6 +595,7 @@ static void conn_destructor(void *buffer, void *unused)
     free(c->suffixlist);
     free(c->iov);
     free(c->msglist);
+    free(c->rlist);
 
     LOCK_STATS();
     mc_stats.conn_structs--;
@@ -655,11 +668,8 @@ conn *conn_new(const int sfd, STATE_FUNC init_state,
     c->rbytes = c->wbytes = 0;
     c->wcurr = c->wbuf;
     c->rcurr = c->rbuf;
-    c->rtype = CONN_RTYPE_NONE;
-    c->rindex = 0; /* used when rtype is HINFO or EINFO */
-    c->ritem = 0;
-    c->rlbytes = 0;
-    c->rltotal = 0; /* used when read with multiple mem blocks */
+    c->rlcurr = 0;
+    c->rlused = 0;
 #ifdef SCAN_COMMAND
     c->pcurr = c->ilist;
 #endif
@@ -1010,85 +1020,89 @@ static void conn_shrink(conn *c)
             c->iov = newbuf;
             c->iovsize = IOV_LIST_INITIAL;
         }
+    /* TODO check error condition? */
+    }
+
+    if (c->rlsize > RITEM_LIST_HIGHWAT) {
+        struct iovec *newbuf = (struct iovec *) realloc((void *)c->rlist, RITEM_LIST_INITIAL * sizeof(c->rlist[0]));
+        if (newbuf) {
+            c->rlist = newbuf;
+            c->rlsize = IOV_LIST_INITIAL;
+        }
     /* TODO check return value */
     }
 }
 
-static void ritem_set_first(conn *c, int rtype, int vleng)
-{
-    c->rtype = rtype;
 
-    if (c->rtype == CONN_RTYPE_MBLCK) {
-        c->membk = MBLCK_GET_HEADBLK(&c->memblist);
-        c->ritem = MBLCK_GET_BODYPTR(c->membk);
-        c->rlbytes = vleng < MBLCK_GET_BODYLEN(&c->memblist)
-                   ? vleng : MBLCK_GET_BODYLEN(&c->memblist);
-        c->rltotal = vleng;
-    }
-    else if (c->rtype == CONN_RTYPE_HINFO) {
-        if (c->hinfo.naddnl == 0) {
-            c->ritem = (char*)c->hinfo.value;
-            c->rlbytes = vleng;
-            c->rltotal = 0;
-        } else {
-            if (c->hinfo.nvalue > 0) {
-                c->ritem = (char*)c->hinfo.value;
-                c->rlbytes = vleng < c->hinfo.nvalue
-                           ? vleng : c->hinfo.nvalue;
-                c->rindex = 0;
-            } else {
-                c->ritem = c->hinfo.addnl[0]->ptr;
-                c->rlbytes = vleng < c->hinfo.addnl[0]->len
-                           ? vleng : c->hinfo.addnl[0]->len;
-                c->rindex = 1;
-            }
-            c->rltotal = vleng;
-        }
+static int add_ritem(conn *c, const void *buf, int len) {
+    if (c->rlused >= c->rlsize) {
+        struct iovec *new_rlist = (struct iovec *)realloc(c->rlist,
+                                  (c->rlsize * 2) * sizeof(struct iovec));
+        if (! new_rlist)
+            return -1;
+        c->rlist = new_rlist;
+        c->rlsize *= 2;
     }
-    else if (c->rtype == CONN_RTYPE_EINFO) {
-        if (c->einfo.naddnl == 0) {
-            c->ritem = (char*)c->einfo.value;
-            c->rlbytes = vleng;
-            c->rltotal = 0;
-        } else {
-            if (c->einfo.nvalue > 0) {
-                c->ritem = (char*)c->einfo.value;
-                c->rlbytes = vleng < c->einfo.nvalue
-                           ? vleng : c->einfo.nvalue;
-                c->rindex = 0;
-            } else {
-                c->ritem = c->einfo.addnl[0]->ptr;
-                c->rlbytes = vleng < c->einfo.addnl[0]->len
-                           ? vleng : c->einfo.addnl[0]->len;
-                c->rindex = 1;
-            }
-            c->rltotal = vleng;
-        }
+    if (len != 0) {
+        c->rlist[c->rlused].iov_base = (void *)buf;
+        c->rlist[c->rlused].iov_len  = len;
+        c->rlused++;
     }
+    return 0;
 }
 
-static void ritem_set_next(conn *c)
-{
-    assert(c->rltotal > 0);
 
-    if (c->rtype == CONN_RTYPE_MBLCK) {
-        c->membk = MBLCK_GET_NEXTBLK(c->membk);
-        c->ritem = MBLCK_GET_BODYPTR(c->membk);
-        c->rlbytes = c->rltotal < MBLCK_GET_BODYLEN(&c->memblist)
-                   ? c->rltotal : MBLCK_GET_BODYLEN(&c->memblist);
+static int add_ritem_mblck(conn *c, mblck_list_t *memblist) {
+    uint32_t rltotal = MBLCK_GET_ITEMCNT(memblist);
+    uint32_t rlbytes;
+    for (mblck_node_t *membk  = MBLCK_GET_HEADBLK(memblist);
+                       membk != NULL && rltotal > 0;
+                       membk  = MBLCK_GET_NEXTBLK(membk)) {
+        rlbytes = rltotal < MBLCK_GET_BODYLEN(memblist)
+                ? rltotal : MBLCK_GET_BODYLEN(memblist);
+        if (add_ritem(c, MBLCK_GET_BODYPTR(membk), rlbytes) != 0)
+            return -1;
+        rltotal -= rlbytes;
     }
-    else if (c->rtype == CONN_RTYPE_HINFO) {
-        c->ritem = c->hinfo.addnl[c->rindex]->ptr;
-        c->rlbytes = c->rltotal < c->hinfo.addnl[c->rindex]->len
-                   ? c->rltotal : c->hinfo.addnl[c->rindex]->len;
-        c->rindex += 1;
+    return 0;
+}
+
+static int add_ritem_hinfo(conn *c, item_info *hinfo) {
+    uint32_t rltotal = hinfo->nbytes;
+    uint32_t rlbytes;
+    if (c->protocol == binary_prot) rltotal -= 2;
+    rlbytes = rltotal < hinfo->nvalue
+            ? rltotal : hinfo->nvalue;
+    if (add_ritem(c, hinfo->value, rlbytes) != 0)
+        return -1;
+    rltotal -= rlbytes;
+    for (int i = 0; i < hinfo->naddnl && rltotal > 0; i++) {
+        rlbytes = rltotal < hinfo->addnl[i]->len
+                ? rltotal : hinfo->addnl[i]->len;
+        if (add_ritem(c, hinfo->addnl[i]->ptr, rlbytes) != 0)
+            return -1;
+        rltotal -= rlbytes;
     }
-    else if (c->rtype == CONN_RTYPE_EINFO) {
-        c->ritem = c->einfo.addnl[c->rindex]->ptr;
-        c->rlbytes = c->rltotal < c->einfo.addnl[c->rindex]->len
-                   ? c->rltotal : c->einfo.addnl[c->rindex]->len;
-        c->rindex += 1;
+    return 0;
+}
+
+static int add_ritem_einfo(conn *c, eitem_info *einfo) {
+    uint32_t vleng = einfo->nbytes;
+    uint32_t rlbytes;
+    if (c->protocol == binary_prot) vleng -= 2;
+    rlbytes = vleng < einfo->nvalue
+            ? vleng : einfo->nvalue;
+    if (add_ritem(c, einfo->value, rlbytes) != 0)
+        return -1;
+    vleng -= rlbytes;
+    for (int i = 0; i < einfo->naddnl && vleng > 0; i++) {
+        rlbytes = vleng < einfo->addnl[i]->len
+                ? vleng : einfo->addnl[i]->len;
+        if (add_ritem(c, einfo->addnl[i]->ptr, rlbytes) != 0)
+            return -1;
+        vleng -= rlbytes;
     }
+    return 0;
 }
 
 /**
@@ -4125,9 +4139,15 @@ static void bin_read_chunk(conn *c, enum bin_substates next_substate, uint32_t c
     }
 
     /* preserve the header in the buffer.. */
-    c->ritem = c->rcurr + sizeof(protocol_binary_request_header);
-    c->rlbytes = chunk;
-    c->rltotal = 0;
+    if (add_ritem(c, c->rcurr + sizeof(protocol_binary_request_header), chunk) != 0)
+    {
+        if (settings.verbose) {
+            mc_logger->log(EXTENSION_LOG_WARNING, c,
+                "%d: Failed to grow rlist. closing connection\n", c->sfd);
+        }
+        conn_set_state(c, conn_closing);
+        return;
+    }
     conn_set_state(c, conn_nread);
 }
 
@@ -4242,9 +4262,10 @@ static void process_bin_sasl_auth(conn *c)
     memcpy(data->data, key, nkey);
 
     c->item = data;
-    c->ritem = data->data + nkey;
-    c->rlbytes = vlen;
-    c->rltotal = 0;
+    if (add_ritem(c, data->data + nkey, vlen) != 0) {
+        write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, vlen);
+        return;
+    }
     conn_set_state(c, conn_nread);
     c->substate = bin_reading_sasl_auth_data;
 }
@@ -4303,7 +4324,6 @@ static void process_bin_complete_sasl_auth(conn *c)
 
     free(c->item);
     c->item = NULL;
-    c->ritem = NULL;
 
     if (settings.verbose) {
         mc_logger->log(EXTENSION_LOG_INFO, c,
@@ -4476,27 +4496,27 @@ static void process_bin_lop_prepare_nread(conn *c)
     }
     if (ret == ENGINE_SUCCESS) {
         mc_engine.v1->get_elem_info(mc_engine.v0, c, ITEM_TYPE_LIST, elem, &c->einfo);
-        ritem_set_first(c, CONN_RTYPE_EINFO, vlen);
-        c->coll_eitem  = (void *)elem;
-        c->coll_ecount = 1;
-        c->coll_op     = OPERATION_LOP_INSERT;
-        c->coll_index  = req->message.body.index;
-        if (req->message.body.create) {
-            c->coll_attrp = &c->coll_attr_space; /* create if not exist */
-            c->coll_attrp->flags    = req->message.body.flags;
-            c->coll_attrp->exptime  = realtime(req->message.body.exptime);
-            c->coll_attrp->maxcount = req->message.body.maxcount;
-            c->coll_attrp->readable = 1;
+        if (add_ritem_einfo(c, &c->einfo) != 0) {
+            write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, vlen);
+            ret = ENGINE_ENOMEM;
         } else {
-            c->coll_attrp = NULL;
+            c->coll_eitem  = (void *)elem;
+            c->coll_ecount = 1;
+            c->coll_op     = OPERATION_LOP_INSERT;
+            c->coll_index  = req->message.body.index;
+            if (req->message.body.create) {
+                c->coll_attrp = &c->coll_attr_space; /* create if not exist */
+                c->coll_attrp->flags    = req->message.body.flags;
+                c->coll_attrp->exptime  = realtime(req->message.body.exptime);
+                c->coll_attrp->maxcount = req->message.body.maxcount;
+                c->coll_attrp->readable = 1;
+            } else {
+                c->coll_attrp = NULL;
+            }
+            conn_set_state(c, conn_nread);
+            c->substate = bin_reading_lop_nread_complete;
         }
-        conn_set_state(c, conn_nread);
-        c->substate = bin_reading_lop_nread_complete;
     } else {
-        if (settings.detail_enabled) {
-            stats_prefix_record_lop_insert(key, nkey, false);
-        }
-        STATS_CMD_NOKEY(c, lop_insert);
         if (ret == ENGINE_E2BIG)
             write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_E2BIG, vlen);
         else if (ret == ENGINE_ENOMEM)
@@ -4504,6 +4524,12 @@ static void process_bin_lop_prepare_nread(conn *c)
         else
             handle_unexpected_errorcode_bin(c, __func__, ret, vlen);
     }
+    if (ret != ENGINE_SUCCESS) {
+        if (settings.detail_enabled) {
+            stats_prefix_record_lop_insert(key, nkey, false);
+        }
+        STATS_CMD_NOKEY(c, lop_insert);
+    }
 }
 
 static void process_bin_lop_insert_complete(conn *c)
@@ -4864,40 +4890,52 @@ static void process_bin_sop_prepare_nread(conn *c)
     if (ret == ENGINE_SUCCESS) {
         if (c->cmd == PROTOCOL_BINARY_CMD_SOP_INSERT) {
             mc_engine.v1->get_elem_info(mc_engine.v0, c, ITEM_TYPE_SET, elem, &c->einfo);
-            ritem_set_first(c, CONN_RTYPE_EINFO, vlen);
-         } else {
-            c->ritem   = ((value_item *)elem)->ptr;
-            c->rlbytes = vlen;
-            c->rltotal = 0;
-         }
-        c->coll_eitem  = (void *)elem;
-        c->coll_ecount = 1;
-        if (c->cmd == PROTOCOL_BINARY_CMD_SOP_INSERT) {
-            protocol_binary_request_sop_insert* req = binary_get_request(c);
-            if (req->message.body.create) {
-                req->message.body.exptime  = ntohl(req->message.body.exptime);
-                req->message.body.maxcount = ntohl(req->message.body.maxcount);
+            if (add_ritem_einfo(c, &c->einfo) != 0){
+                write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, 0);
+                ret = ENGINE_ENOMEM;
             }
-            c->coll_op     = OPERATION_SOP_INSERT;
-            if (req->message.body.create) {
-                c->coll_attrp = &c->coll_attr_space; /* create if not exist */
-                c->coll_attrp->flags    = req->message.body.flags;
-                c->coll_attrp->exptime  = realtime(req->message.body.exptime);
-                c->coll_attrp->maxcount = req->message.body.maxcount;
-                c->coll_attrp->readable = 1;
-            } else {
-                c->coll_attrp = NULL;
+        } else if (add_ritem(c, ((value_item *)elem)->ptr, vlen) != 0){
+            write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, 0);
+            ret = ENGINE_ENOMEM;
+        }
+        if (ret == ENGINE_SUCCESS) {
+            c->coll_eitem  = (void *)elem;
+            c->coll_ecount = 1;
+            if (c->cmd == PROTOCOL_BINARY_CMD_SOP_INSERT) {
+                protocol_binary_request_sop_insert* req = binary_get_request(c);
+                if (req->message.body.create) {
+                    req->message.body.exptime  = ntohl(req->message.body.exptime);
+                    req->message.body.maxcount = ntohl(req->message.body.maxcount);
+                }
+                c->coll_op     = OPERATION_SOP_INSERT;
+                if (req->message.body.create) {
+                    c->coll_attrp = &c->coll_attr_space; /* create if not exist */
+                    c->coll_attrp->flags    = req->message.body.flags;
+                    c->coll_attrp->exptime  = realtime(req->message.body.exptime);
+                    c->coll_attrp->maxcount = req->message.body.maxcount;
+                    c->coll_attrp->readable = 1;
+                } else {
+                    c->coll_attrp = NULL;
+                }
+            } else if (c->cmd == PROTOCOL_BINARY_CMD_SOP_DELETE) {
+                protocol_binary_request_sop_delete* req = binary_get_request(c);
+                c->coll_op     = OPERATION_SOP_DELETE;
+                c->coll_drop   = (req->message.body.drop ? true : false);
+            } else { /* PROTOCOL_BINARY_CMD_SOP_EXIST */
+                c->coll_op     = OPERATION_SOP_EXIST;
             }
-        } else if (c->cmd == PROTOCOL_BINARY_CMD_SOP_DELETE) {
-            protocol_binary_request_sop_delete* req = binary_get_request(c);
-            c->coll_op     = OPERATION_SOP_DELETE;
-            c->coll_drop   = (req->message.body.drop ? true : false);
-        } else { /* PROTOCOL_BINARY_CMD_SOP_EXIST */
-            c->coll_op     = OPERATION_SOP_EXIST;
+            conn_set_state(c, conn_nread);
+            c->substate = bin_reading_sop_nread_complete;
         }
-        conn_set_state(c, conn_nread);
-        c->substate = bin_reading_sop_nread_complete;
     } else {
+        if (ret == ENGINE_E2BIG)
+            write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_E2BIG, vlen);
+        else if (ret == ENGINE_ENOMEM)
+            write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, vlen);
+        else
+            handle_unexpected_errorcode_bin(c, __func__, ret, vlen);
+    }
+    if (ret != ENGINE_SUCCESS){
         if (c->cmd == PROTOCOL_BINARY_CMD_SOP_INSERT) {
             if (settings.detail_enabled)
                 stats_prefix_record_sop_insert(key, nkey, false);
@@ -4911,12 +4949,6 @@ static void process_bin_sop_prepare_nread(conn *c)
                stats_prefix_record_sop_exist(key, nkey, false);
             STATS_CMD_NOKEY(c, sop_exist);
         }
-        if (ret == ENGINE_E2BIG)
-            write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_E2BIG, vlen);
-        else if (ret == ENGINE_ENOMEM)
-            write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, vlen);
-        else
-            handle_unexpected_errorcode_bin(c, __func__, ret, vlen);
     }
 }
 
@@ -5334,36 +5366,36 @@ static void process_bin_bop_prepare_nread(conn *c)
     }
     if (ret == ENGINE_SUCCESS) {
         mc_engine.v1->get_elem_info(mc_engine.v0, c, ITEM_TYPE_BTREE, elem, &c->einfo);
-        if (c->einfo.nscore == 0) {
-            memcpy((void*)c->einfo.score, req->message.body.bkey, sizeof(uint64_t));
+        if (add_ritem_einfo(c, &c->einfo) != 0) {
+            write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, vlen);
+            ret = ENGINE_ENOMEM;
         } else {
-            memcpy((void*)c->einfo.score, req->message.body.bkey, c->einfo.nscore);
-        }
-        if (c->einfo.neflag > 0) {
-            memcpy((void*)c->einfo.eflag, req->message.body.eflag, c->einfo.neflag);
-        }
+            if (c->einfo.nscore == 0) {
+                memcpy((void*)c->einfo.score, req->message.body.bkey, sizeof(uint64_t));
+            } else {
+                memcpy((void*)c->einfo.score, req->message.body.bkey, c->einfo.nscore);
+            }
+            if (c->einfo.neflag > 0) {
+                memcpy((void*)c->einfo.eflag, req->message.body.eflag, c->einfo.neflag);
+            }
 
-        ritem_set_first(c, CONN_RTYPE_EINFO, vlen);
-        c->coll_eitem  = (void *)elem;
-        c->coll_ecount = 1;
-        c->coll_op     = (c->cmd == PROTOCOL_BINARY_CMD_BOP_INSERT ? OPERATION_BOP_INSERT
-                                                                   : OPERATION_BOP_UPSERT);
-        if (req->message.body.create) {
-            c->coll_attrp = &c->coll_attr_space; /* create if not exist */
-            c->coll_attrp->flags    = req->message.body.flags;
-            c->coll_attrp->exptime  = realtime(req->message.body.exptime);
-            c->coll_attrp->maxcount = req->message.body.maxcount;
-            c->coll_attrp->readable = 1;
-        } else {
-            c->coll_attrp = NULL;
+            c->coll_eitem  = (void *)elem;
+            c->coll_ecount = 1;
+            c->coll_op     = (c->cmd == PROTOCOL_BINARY_CMD_BOP_INSERT ? OPERATION_BOP_INSERT
+                                                                       : OPERATION_BOP_UPSERT);
+            if (req->message.body.create) {
+                c->coll_attrp = &c->coll_attr_space; /* create if not exist */
+                c->coll_attrp->flags    = req->message.body.flags;
+                c->coll_attrp->exptime  = realtime(req->message.body.exptime);
+                c->coll_attrp->maxcount = req->message.body.maxcount;
+                c->coll_attrp->readable = 1;
+            } else {
+                c->coll_attrp = NULL;
+            }
+            conn_set_state(c, conn_nread);
+            c->substate = bin_reading_bop_nread_complete;
         }
-        conn_set_state(c, conn_nread);
-        c->substate = bin_reading_bop_nread_complete;
     } else {
-        if (settings.detail_enabled) {
-            stats_prefix_record_bop_insert(key, nkey, false);
-        }
-        STATS_CMD_NOKEY(c, bop_insert);
         if (ret == ENGINE_E2BIG)
             write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_E2BIG, vlen);
         else if (ret == ENGINE_ENOMEM)
@@ -5371,6 +5403,12 @@ static void process_bin_bop_prepare_nread(conn *c)
         else
             handle_unexpected_errorcode_bin(c, __func__, ret, vlen);
     }
+    if (ret != ENGINE_SUCCESS) {
+        if (settings.detail_enabled) {
+            stats_prefix_record_bop_insert(key, nkey, false);
+        }
+        STATS_CMD_NOKEY(c, bop_insert);
+    }
 }
 
 static void process_bin_bop_insert_complete(conn *c)
@@ -5572,19 +5610,17 @@ static void process_bin_bop_update_prepare_nread(conn *c)
             ((value_item*)elem)->len = vlen + 2;
     }
     if (ret == ENGINE_SUCCESS) {
-        c->ritem       = ((value_item *)elem)->ptr;
-        c->rlbytes     = vlen;
-        c->rltotal     = 0;
-        c->coll_eitem  = (void *)elem;
-        c->coll_ecount = 1;
-        c->coll_op     = OPERATION_BOP_UPDATE;
-        conn_set_state(c, conn_nread);
-        c->substate = bin_reading_bop_update_nread_complete;
-    } else {
-        if (settings.detail_enabled) {
-            stats_prefix_record_bop_update(key, nkey, false);
+        if (add_ritem(c, ((value_item *)elem)->ptr, vlen) != 0) {
+            write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, vlen);
+            ret = ENGINE_ENOMEM;
+        } else {
+            c->coll_eitem  = (void *)elem;
+            c->coll_ecount = 1;
+            c->coll_op     = OPERATION_BOP_UPDATE;
+            conn_set_state(c, conn_nread);
+            c->substate = bin_reading_bop_update_nread_complete;
         }
-        STATS_CMD_NOKEY(c, bop_update);
+    } else {
         /* ret == ENGINE_E2BIG || ret == ENGINE_ENOMEM */
         if (ret == ENGINE_E2BIG)
             write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_E2BIG, vlen);
@@ -5593,6 +5629,12 @@ static void process_bin_bop_update_prepare_nread(conn *c)
         else
             handle_unexpected_errorcode_bin(c, __func__, ret, vlen);
     }
+    if (ret != ENGINE_ENOMEM) {
+        if (settings.detail_enabled) {
+            stats_prefix_record_bop_update(key, nkey, false);
+        }
+        STATS_CMD_NOKEY(c, bop_update);
+    }
 }
 
 static void process_bin_bop_delete(conn *c)
@@ -6043,13 +6085,17 @@ static void process_bin_bop_prepare_nread_keys(conn *c)
     } while(0);
 
     if (ret == ENGINE_SUCCESS) {
-        c->coll_strkeys = (void*)&c->memblist;
-        ritem_set_first(c, CONN_RTYPE_MBLCK, vlen);
-        c->coll_eitem  = (void *)elem;
-        c->coll_ecount = 0;
-        c->coll_op = (c->cmd==PROTOCOL_BINARY_CMD_BOP_MGET ? OPERATION_BOP_MGET : OPERATION_BOP_SMGET);
-        conn_set_state(c, conn_nread);
-        c->substate = bin_reading_bop_nread_keys_complete;
+        if (add_ritem_mblck(c, &c->memblist) != 0) {
+            write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, vlen);
+            return;
+        } else {
+            c->coll_strkeys = (void*)&c->memblist;
+            c->coll_eitem  = (void *)elem;
+            c->coll_ecount = 0;
+            c->coll_op = (c->cmd==PROTOCOL_BINARY_CMD_BOP_MGET ? OPERATION_BOP_MGET : OPERATION_BOP_SMGET);
+            conn_set_state(c, conn_nread);
+            c->substate = bin_reading_bop_nread_keys_complete;
+        }
     } else {
         /* ret == ENGINE_EBADVALUE || ret == ENGINE_ENOMEM */
         if (ret == ENGINE_EBADVALUE)
@@ -7121,6 +7167,9 @@ static void process_bin_update(conn *c)
             mc_engine.v1->release(mc_engine.v0, c, it);
             write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, vlen);
             ret = ENGINE_ENOMEM;
+        } else if (add_ritem_hinfo(c, &c->hinfo) != 0) {
+            write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, vlen);
+            ret = ENGINE_ENOMEM;
         } else {
             if (c->cmd == PROTOCOL_BINARY_CMD_ADD)
                 c->store_op = OPERATION_ADD;
@@ -7136,7 +7185,6 @@ static void process_bin_update(conn *c)
             }
 
             c->item = it;
-            ritem_set_first(c, CONN_RTYPE_HINFO, vlen);
             conn_set_state(c, conn_nread);
             c->substate = bin_read_set_value;
         }
@@ -7201,6 +7249,8 @@ static void process_bin_append_prepend(conn *c)
         if (!mc_engine.v1->get_item_info(mc_engine.v0, c, it, &c->hinfo)) {
             mc_engine.v1->release(mc_engine.v0, c, it);
             write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, vlen);
+        } else if (add_ritem_hinfo(c, &c->hinfo) != 0) {
+            write_bin_packet(c, PROTOCOL_BINARY_RESPONSE_ENOMEM, vlen);
         } else {
             if (c->cmd == PROTOCOL_BINARY_CMD_APPEND)
                 c->store_op = OPERATION_APPEND;
@@ -7210,7 +7260,6 @@ static void process_bin_append_prepend(conn *c)
                 assert(0);
 
             c->item = it;
-            ritem_set_first(c, CONN_RTYPE_HINFO, vlen);
             conn_set_state(c, conn_nread);
             c->substate = bin_read_set_value;
         }
@@ -7529,6 +7578,8 @@ static int try_read_command_binary(conn *c)
     c->msgcurr = 0;
     c->msgused = 0;
     c->iovused = 0;
+    c->rlcurr = 0;
+    c->rlused = 0;
     int ret = add_msghdr(c);
     assert(ret == 0);
 
@@ -8392,12 +8443,12 @@ static void process_prepare_nread_keys(conn *c, uint32_t vlen, uint32_t kcnt, bo
     ENGINE_ERROR_CODE ret = ENGINE_SUCCESS;
 
     /* allocate memory blocks needed */
-    if (mblck_list_alloc(&c->thread->mblck_pool, 1, vlen, &c->memblist) < 0) {
+    if (mblck_list_alloc(&c->thread->mblck_pool, 1, vlen, &c->memblist) < 0 ||
+        add_ritem_mblck(c, &c->memblist) != 0) {
         ret = ENGINE_ENOMEM;
     }
     if (ret == ENGINE_SUCCESS) {
         c->coll_strkeys = (void*)&c->memblist;
-        ritem_set_first(c, CONN_RTYPE_MBLCK, vlen);
         c->coll_op = (return_cas ? OPERATION_MGETS : OPERATION_MGET);
         conn_set_state(c, conn_nread);
     } else {
@@ -8489,9 +8540,11 @@ static void process_update_command(conn *c, token_t *tokens, const size_t ntoken
             mc_engine.v1->release(mc_engine.v0, c, it);
             out_string(c, "SERVER_ERROR error getting item data");
             ret = ENGINE_ENOMEM;
+        } else if (add_ritem_hinfo(c, &c->hinfo) != 0) {
+            out_string(c, "SERVER_ERROR out of memory");
+            ret = ENGINE_ENOMEM;
         } else {
             c->item = it;
-            ritem_set_first(c, CONN_RTYPE_HINFO, vlen);
             c->store_op = store_op;
             conn_set_state(c, conn_nread);
         }
@@ -9543,10 +9596,9 @@ static void process_extension_command(conn *c, token_t *tokens, size_t ntokens)
                 conn_set_state(c, conn_new_cmd);
             }
         }
+    } else if (add_ritem(c, ptr, nbytes) != 0) {
+        out_string(c, "SERVER ERROR out of memory");
     } else {
-        c->ritem = ptr;
-        c->rlbytes = nbytes;
-        c->rltotal = 0;
         c->ascii_cmd = cmd;
         /* NOT SUPPORTED YET! */
         conn_set_state(c, conn_nread);
@@ -10260,20 +10312,26 @@ static void process_lop_prepare_nread(conn *c, int cmd, size_t vlen,
     }
     if (ret == ENGINE_SUCCESS) {
         mc_engine.v1->get_elem_info(mc_engine.v0, c, ITEM_TYPE_LIST, elem, &c->einfo);
-        ritem_set_first(c, CONN_RTYPE_EINFO, vlen);
-        c->coll_eitem  = (void *)elem;
-        c->coll_ecount = 1;
-        c->coll_op     = OPERATION_LOP_INSERT;
-        c->coll_index  = index;
-        conn_set_state(c, conn_nread);
+        if (add_ritem_einfo(c, &c->einfo) != 0) {
+            out_string(c, "SERVER ERROR out of memory");
+            ret = ENGINE_ENOMEM;
+        } else {
+            c->coll_eitem  = (void *)elem;
+            c->coll_ecount = 1;
+            c->coll_op     = OPERATION_LOP_INSERT;
+            c->coll_index  = index;
+            conn_set_state(c, conn_nread);
+        }
     } else {
+        if (ret == ENGINE_E2BIG)       out_string(c, "CLIENT_ERROR too large value");
+        else if (ret == ENGINE_ENOMEM) out_string(c, "SERVER_ERROR out of memory");
+        else handle_unexpected_errorcode_ascii(c, __func__, ret);
+    }
+    if (ret != ENGINE_SUCCESS) {
         if (settings.detail_enabled) {
             stats_prefix_record_lop_insert(key, nkey, false);
         }
         STATS_CMD_NOKEY(c, lop_insert);
-        if (ret == ENGINE_E2BIG)       out_string(c, "CLIENT_ERROR too large value");
-        else if (ret == ENGINE_ENOMEM) out_string(c, "SERVER_ERROR out of memory");
-        else handle_unexpected_errorcode_ascii(c, __func__, ret);
 
         if (ret != ENGINE_DISCONNECT) {
             /* swallow the data line */
@@ -10657,16 +10715,20 @@ static void process_sop_prepare_nread(conn *c, int cmd, size_t vlen, char *key,
     if (ret == ENGINE_SUCCESS) {
         if (cmd == (int)OPERATION_SOP_INSERT) {
             mc_engine.v1->get_elem_info(mc_engine.v0, c, ITEM_TYPE_SET, elem, &c->einfo);
-            ritem_set_first(c, CONN_RTYPE_EINFO, vlen);
-        } else {
-            c->ritem = ((value_item *)elem)->ptr;
-            c->rlbytes = vlen;
-            c->rltotal = 0;
+            if (add_ritem_einfo(c, &c->einfo) != 0) {
+                out_string(c, "SERVER_ERROR out of memory");
+                ret = ENGINE_ENOMEM;
+            }
+        } else if (add_ritem(c, ((value_item *)elem)->ptr, vlen)){
+            out_string(c, "SERVER_ERROR out of memory");
+            ret = ENGINE_ENOMEM;
+        }
+        if (ret == ENGINE_SUCCESS) {
+            c->coll_eitem  = (void *)elem;
+            c->coll_ecount = 1;
+            c->coll_op     = cmd;
+            conn_set_state(c, conn_nread);
         }
-        c->coll_eitem  = (void *)elem;
-        c->coll_ecount = 1;
-        c->coll_op     = cmd;
-        conn_set_state(c, conn_nread);
     } else {
         if (cmd == (int)OPERATION_SOP_INSERT) {
             if (settings.detail_enabled)
@@ -11333,21 +11395,24 @@ static void process_bop_update_prepare_nread(conn *c, int cmd,
             ((value_item*)elem)->len = vlen;
     }
     if (ret == ENGINE_SUCCESS) {
-        c->ritem   = ((value_item *)elem)->ptr;
-        c->rlbytes = vlen;
-        c->rltotal = 0;
-        c->coll_eitem  = (void *)elem;
-        c->coll_ecount = 1;
-        c->coll_op     = cmd;
-        conn_set_state(c, conn_nread);
+        if (add_ritem(c, ((value_item *)elem)->ptr, vlen) != 0) {
+            out_string(c, "SERVER_ERROR out of memory");
+            ret = ENGINE_ENOMEM;
+        } else {
+            c->coll_eitem  = (void *)elem;
+            c->coll_ecount = 1;
+            c->coll_op     = cmd;
+            conn_set_state(c, conn_nread);
+        }
     } else {
+        if (ret == ENGINE_E2BIG) out_string(c, "CLIENT_ERROR too large value");
+        else                     out_string(c, "SERVER_ERROR out of memory");
+    }
+    if (ret != ENGINE_SUCCESS) {
         if (settings.detail_enabled) {
             stats_prefix_record_bop_update(key, nkey, false);
         }
         STATS_CMD_NOKEY(c, bop_update);
-        if (ret == ENGINE_E2BIG) out_string(c, "CLIENT_ERROR too large value");
-        else                     out_string(c, "SERVER_ERROR out of memory");
-
         /* swallow the data line */
         c->sbytes = vlen;
         if (c->state == conn_write) {
@@ -11374,23 +11439,28 @@ static void process_bop_prepare_nread(conn *c, int cmd, char *key, size_t nkey,
     }
     if (ret == ENGINE_SUCCESS) {
         mc_engine.v1->get_elem_info(mc_engine.v0, c, ITEM_TYPE_BTREE, elem, &c->einfo);
-        memcpy((void*)c->einfo.score, bkey, (c->einfo.nscore==0 ? sizeof(uint64_t) : c->einfo.nscore));
-        if (c->einfo.neflag > 0)
-            memcpy((void*)c->einfo.eflag, eflag, c->einfo.neflag);
-        ritem_set_first(c, CONN_RTYPE_EINFO, vlen);
-        c->coll_eitem  = (void *)elem;
-        c->coll_ecount = 1;
-        c->coll_op     = cmd; /* OPERATION_BOP_INSERT | OPERATION_BOP_UPSERT */
-        conn_set_state(c, conn_nread);
+        if (add_ritem_einfo(c, &c->einfo) != 0) {
+            out_string(c, "SERVER_ERROR out of memory");
+            ret = ENGINE_ENOMEM;
+        } else {
+            memcpy((void*)c->einfo.score, bkey, (c->einfo.nscore==0 ? sizeof(uint64_t) : c->einfo.nscore));
+            if (c->einfo.neflag > 0)
+                memcpy((void*)c->einfo.eflag, eflag, c->einfo.neflag);
+            c->coll_eitem  = (void *)elem;
+            c->coll_ecount = 1;
+            c->coll_op     = cmd; /* OPERATION_BOP_INSERT | OPERATION_BOP_UPSERT */
+            conn_set_state(c, conn_nread);
+        }
     } else {
+        if (ret == ENGINE_E2BIG)       out_string(c, "CLIENT_ERROR too large value");
+        else if (ret == ENGINE_ENOMEM) out_string(c, "SERVER_ERROR out of memory");
+        else handle_unexpected_errorcode_ascii(c, __func__, ret);
+    }
+    if (ret != ENGINE_SUCCESS) {
         if (settings.detail_enabled) {
             stats_prefix_record_bop_insert(key, nkey, false);
         }
         STATS_CMD_NOKEY(c, bop_insert);
-        if (ret == ENGINE_E2BIG)       out_string(c, "CLIENT_ERROR too large value");
-        else if (ret == ENGINE_ENOMEM) out_string(c, "SERVER_ERROR out of memory");
-        else handle_unexpected_errorcode_ascii(c, __func__, ret);
-
         if (ret != ENGINE_DISCONNECT) {
             /* swallow the data line */
             c->sbytes = vlen;
@@ -11468,13 +11538,21 @@ static void process_bop_prepare_nread_keys(conn *c, int cmd, uint32_t vlen, uint
         }
     }
     if (ret == ENGINE_SUCCESS) {
-        c->coll_strkeys = (void*)&c->memblist;
-        ritem_set_first(c, CONN_RTYPE_MBLCK, vlen);
-        c->coll_eitem  = (void *)elem;
-        c->coll_ecount = 0;
-        c->coll_op = cmd;
-        conn_set_state(c, conn_nread);
+        if (add_ritem_mblck(c, &c->memblist) != 0) {
+            out_string(c, "SERVER_ERROR out of memory");
+            ret = ENGINE_ENOMEM;
+        } else {
+            c->coll_strkeys = (void*)&c->memblist;
+            c->coll_eitem  = (void *)elem;
+            c->coll_ecount = 0;
+            c->coll_op = cmd;
+            conn_set_state(c, conn_nread);
+        }
     } else {
+        /* ret == ENGINE_ENOMEM */
+        out_string(c, "SERVER_ERROR out of memory");
+    }
+    if (ret != ENGINE_SUCCESS) {
 #ifdef SUPPORT_BOP_MGET
         if (cmd == OPERATION_BOP_MGET)
             STATS_CMD_NOKEY(c, bop_mget);
@@ -11483,9 +11561,6 @@ static void process_bop_prepare_nread_keys(conn *c, int cmd, uint32_t vlen, uint
         if (cmd == OPERATION_BOP_SMGET)
             STATS_CMD_NOKEY(c, bop_smget);
 #endif
-        /* ret == ENGINE_ENOMEM */
-        out_string(c, "SERVER_ERROR out of memory");
-
         /* swallow the data line */
         assert(c->state == conn_write);
         c->sbytes = vlen;
@@ -11833,18 +11908,27 @@ static void process_mop_prepare_nread(conn *c, int cmd, char *key, size_t nkey,
     if (ret == ENGINE_SUCCESS) {
         if (cmd == OPERATION_MOP_INSERT) {
             mc_engine.v1->get_elem_info(mc_engine.v0, c, ITEM_TYPE_MAP, elem, &c->einfo);
-            ritem_set_first(c, CONN_RTYPE_EINFO, vlen);
-        } else {
-            c->ritem   = ((value_item *)elem)->ptr;
-            c->rlbytes = vlen;
-            c->rltotal = 0;
+            if (add_ritem_einfo(c, &c->einfo) != 0) {
+                out_string(c, "SERVER_ERROR out of memory");
+                ret = ENGINE_ENOMEM;
+            }
+        } else if (add_ritem(c, ((value_item *)elem)->ptr, vlen)){
+            out_string(c, "SERVER_ERROR out of memory");
+            ret = ENGINE_ENOMEM;
+        }
+        if (ret == ENGINE_SUCCESS) {
+            c->coll_eitem  = (void *)elem;
+            c->coll_ecount = 1;
+            c->coll_op     = cmd;
+            c->coll_field  = *field;
+            conn_set_state(c, conn_nread);
         }
-        c->coll_eitem  = (void *)elem;
-        c->coll_ecount = 1;
-        c->coll_op     = cmd;
-        c->coll_field  = *field;
-        conn_set_state(c, conn_nread);
     } else {
+        if (ret == ENGINE_E2BIG)       out_string(c, "CLIENT_ERROR too large value");
+        else if (ret == ENGINE_ENOMEM) out_string(c, "SERVER_ERROR out of memory");
+        else handle_unexpected_errorcode_ascii(c, __func__, ret);
+    }
+    if (ret != ENGINE_SUCCESS) {
         if (settings.detail_enabled) {
             stats_prefix_record_mop_insert(key, nkey, false);
         }
@@ -11853,10 +11937,6 @@ static void process_mop_prepare_nread(conn *c, int cmd, char *key, size_t nkey,
         } else if (cmd == OPERATION_MOP_UPDATE) {
             STATS_CMD_NOKEY(c, mop_update);
         }
-        if (ret == ENGINE_E2BIG)       out_string(c, "CLIENT_ERROR too large value");
-        else if (ret == ENGINE_ENOMEM) out_string(c, "SERVER_ERROR out of memory");
-        else handle_unexpected_errorcode_ascii(c, __func__, ret);
-
         if (ret != ENGINE_DISCONNECT) {
             /* swallow the data line */
             c->sbytes = vlen;
@@ -11878,21 +11958,26 @@ static void process_mop_prepare_nread_fields(conn *c, int cmd, char *key, size_t
         ret = ENGINE_ENOMEM;
     }
     if (ret == ENGINE_SUCCESS) {
-        c->coll_strkeys = (void*)&c->memblist;
-        ritem_set_first(c, CONN_RTYPE_MBLCK, flen);
-        c->coll_ecount = 1;
-        c->coll_op = cmd;
-        c->coll_lenkeys = flen;
-        conn_set_state(c, conn_nread);
+        if (add_ritem_mblck(c, &c->memblist) != 0) {
+            out_string(c, "SERVER_ERROR out of memory");
+            ret = ENGINE_ENOMEM;
+        } else {
+            c->coll_strkeys = (void*)&c->memblist;
+            c->coll_ecount = 1;
+            c->coll_op = cmd;
+            c->coll_lenkeys = flen;
+            conn_set_state(c, conn_nread);
+        }
     } else {
+        /* ret == ENGINE_ENOMEM */
+        out_string(c, "SERVER_ERROR out of memory");
+    }
+    if (ret != ENGINE_SUCCESS) {
         if (cmd == OPERATION_MOP_DELETE) {
             STATS_CMD_NOKEY(c, mop_delete);
         } else if (cmd == OPERATION_MOP_GET) {
             STATS_CMD_NOKEY(c, mop_get);
         }
-        /* ret == ENGINE_ENOMEM */
-        out_string(c, "SERVER_ERROR out of memory");
-
         /* swallow the data line */
         c->sbytes = flen;
         if (c->state == conn_write) {
@@ -13079,6 +13164,8 @@ static void process_command_ascii(conn *c, char *command, int cmdlen)
     c->msgcurr = 0;
     c->msgused = 0;
     c->iovused = 0;
+    c->rlcurr = 0;
+    c->rlused = 0;
     if (add_msghdr(c) != 0) {
         out_string(c, "SERVER_ERROR out of memory preparing response");
         return;
@@ -13767,7 +13854,7 @@ bool conn_nread(conn *c)
 {
     ssize_t res;
 
-    if (c->rlbytes == 0) {
+    if (c->rlcurr == c->rlused) {
         complete_nread(c);
 
         /* complete_nread eventually calls write functions
@@ -13785,6 +13872,11 @@ bool conn_nread(conn *c)
         return true;
     }
 
+    if (c->rlbytes == 0) {
+        c->ritem   = c->rlist[c->rlcurr].iov_base;
+        c->rlbytes = c->rlist[c->rlcurr].iov_len;
+    }
+
     /* first check if we have leftovers in the conn_read buffer */
     while (c->rbytes > 0) {
         int tocopy = c->rbytes > c->rlbytes ? c->rlbytes : c->rbytes;
@@ -13795,14 +13887,14 @@ bool conn_nread(conn *c)
         c->rlbytes -= tocopy;
         c->rcurr += tocopy;
         c->rbytes -= tocopy;
-        if (c->rltotal > 0) { /* string block read */
-            c->rltotal -= tocopy;
-            if (c->rlbytes == 0 && c->rltotal > 0) {
-                ritem_set_next(c);
-                continue;
+        if (c->rlbytes == 0) { /* string block read */
+            c->rlcurr++ ;
+            if (c->rlcurr < c->rlused) {
+                c->ritem   = c->rlist[c->rlcurr].iov_base;
+                c->rlbytes = c->rlist[c->rlcurr].iov_len;
             }
         }
-        if (c->rlbytes == 0) {
+        if (c->rlcurr == c->rlused) {
             return true;
         }
     }
@@ -13816,11 +13908,8 @@ bool conn_nread(conn *c)
         }
         c->ritem += res;
         c->rlbytes -= res;
-        if (c->rltotal > 0) {
-            c->rltotal -= res;
-            if (c->rlbytes == 0 && c->rltotal > 0) {
-                ritem_set_next(c);
-            }
+        if (c->rlbytes == 0) {
+            c->rlcurr++;
         }
         return true;
     }
diff --git a/memcached.h b/memcached.h
index b2a49df1d..bd72a5aef 100644
--- a/memcached.h
+++ b/memcached.h
@@ -76,11 +76,15 @@
 /** Initial number of sendmsg() argument structures to allocate. */
 #define MSG_LIST_INITIAL 10
 
+/** Initial size of list of items being read. */
+#define RITEM_LIST_INITIAL 1
+
 /** High water marks for buffer shrinking */
 #define READ_BUFFER_HIGHWAT 8192
 #define ITEM_LIST_HIGHWAT 400
 #define IOV_LIST_HIGHWAT 600
 #define MSG_LIST_HIGHWAT 100
+#define RITEM_LIST_HIGHWAT 400
 
 /* Binary protocol stuff */
 #define MIN_BIN_PKT_LENGTH 16
@@ -261,12 +265,6 @@ typedef bool (*STATE_FUNC)(conn *);
 /**
  * The structure representing a connection into memcached.
  */
-/* rtype in connection */
-#define CONN_RTYPE_NONE  0
-#define CONN_RTYPE_MBLCK 1
-#define CONN_RTYPE_HINFO 2
-#define CONN_RTYPE_EINFO 3
-
 struct conn {
     int    sfd;
     short  nevents;
@@ -290,13 +288,16 @@ struct conn {
     STATE_FUNC   write_and_go;
     void        *write_and_free; /** free this memory after finishing writing */
 
-    int         rtype;  /* CONN_RTYPE_XXXXX */
-    int         rindex; /* used when rtype is HINFO or EINFO */
-    char       *ritem;  /** when we read in an item's value, it goes here */
-    uint32_t    rlbytes;
+    /** data for nread state */
+    struct iovec    *rlist;   /** list to read data except commands if needed */
+    uint32_t         rlcurr;  /** element in rlist[] being read now */
+    uint32_t         rlsize;  /** total allocated size of rlist */
+    uint32_t         rlused;  /** number of elements used in rlist[] */
+
+    char            *ritem;   /** data pointer being read currently */
+    uint32_t         rlbytes; /** data length being read currently */
+
     /* use memory blocks */
-    uint32_t    rltotal;    /* Used when read data with memory block */
-    mblck_node_t *membk;    /* current memory block pointer */
     mblck_list_t  memblist; /* (key or field) string memory block list */
 
     /* hash item and elem item info */