[svn-r25226] - implement and use H5Dquery_ff() when creating views (not tested with indexing enabled yet).

- cleanup old indexing code in view create at the client as it's not needed anymore.

10 files changed, 258 insertions, 141 deletions

diff --git a/examples/h5ff_client_obj.c b/examples/h5ff_client_obj.c
index 7dcdbbe..c5e75d3 100644
--- a/examples/h5ff_client_obj.c
+++ b/examples/h5ff_client_obj.c
@@ -250,8 +250,7 @@ int main(int argc, char **argv) {
 

     /* check if an object exists. This is asynchronous, so checking

        the value should be done after the wait */

-    ret = H5Oexists_by_name_ff(file_id, "G1", &exists, 

-                               H5P_DEFAULT, rid2, e_stack);

+    ret = H5Oexists_by_name_ff(file_id, "G1", &exists, H5P_DEFAULT, rid2, e_stack);

     assert(ret == 0);

 

     if(my_rank == 0) {

diff --git a/src/H5FF.c b/src/H5FF.c
index 522a949..5ed8cb1 100644
--- a/src/H5FF.c
+++ b/src/H5FF.c
@@ -4799,10 +4799,7 @@ H5VLiod_get_file_id(const char *filename, iod_handle_t coh, hid_t fapl_id, hid_t
     iod_handles_t root_oh;           /* root object handle */
     iod_cont_trans_stat_t *tids = NULL;
     iod_trans_id_t rtid;
-    uint64_t kv_oid_index, array_oid_index, blob_oid_index;
     iod_handle_t mdkv_oh;
-    iod_checksum_t *iod_cs = NULL;
-    iod_size_t key_size = 0, val_size = 0;
     hid_t fcpl_id;
     uint32_t cs_scope;
     iod_ret_t ret;
@@ -4855,7 +4852,7 @@ H5VLiod_get_file_id(const char *filename, iod_handle_t coh, hid_t fapl_id, hid_t
 
     ret = iod_trans_start(coh, &rtid, NULL, 0, IOD_TRANS_R, NULL);
     if(ret < 0)
-        HGOTO_ERROR_FF(ret, "can't start transaction");
+        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "can't start transaction");
 
     /* open the root group */
     IOD_OBJID_SETOWNER_APP(root_id)
@@ -5000,4 +4997,129 @@ done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5VLiod_close_file_id() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:	H5Dquery
+ *
+ * Purpose:     returns a dataspace selection of dataset elements that
+ *              matches the query
+ *
+ * Return:	Success:	The ID for a dataspace selection.
+ *		Failure:	FAIL
+ *
+ * Programmer:	Mohamad Chaarawi
+ *		May 29, 2014
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+H5Dquery_ff(hid_t dset_id, hid_t query_id, hid_t scope_id, hid_t rcxt_id)
+{
+    void *dset = NULL;
+    H5P_genplist_t *xxpl_plist = NULL, *plist = NULL; /* Property list pointer */
+    hid_t xxpl_id = FAIL;
+    unsigned plugin_id;
+    void *buf = NULL;
+    hid_t type_id=FAIL, space_id=scope_id, dset_space_id=FAIL;
+    hbool_t use_region_scope = TRUE;
+    hid_t ret_value = FAIL;
+
+    FUNC_ENTER_API(FAIL)
+
+    if(NULL == (dset = (void *)H5I_object_verify(dset_id, H5I_DATASET)))
+	HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a dataset");
+
+#ifdef H5_HAVE_INDEXING
+    /* Use indexing query callback if it exists */
+    if (!(plugin_id = H5VL_iod_dataset_get_index_plugin_id(dset))) {
+        void *idx_handle = NULL; /* index */
+        H5X_class_t *idx_class = NULL;
+
+        if (NULL == (idx_class = H5X_registered(plugin_id)))
+            HGOTO_ERROR(H5E_INDEX, H5E_CANTGET, FAIL, "can't get index plugin class");
+
+        if(NULL == (plist = H5I_object(H5P_INDEX_XFER_DEFAULT)))
+            HGOTO_ERROR(H5E_PLIST, H5E_NOTFOUND, FAIL, "property object doesn't exist");
+        if((xxpl_id = H5P_copy_plist((H5P_genplist_t *)plist, TRUE)) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTCOPY, FAIL, "can't copy property list");
+
+        /* store the read context ID in the xxpl */
+        if (NULL == (xxpl_plist = (H5P_genplist_t *) H5I_object(xxpl_id)))
+            HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+        if (H5P_set(xxpl_plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id");
+
+        if (NULL == idx_class->query)
+            HGOTO_ERROR(H5E_INDEX, H5E_BADVALUE, FAIL, "plugin query callback is not defined");
+        if (FAIL == idx_class->query(idx_handle, query_id, xxpl_id, &ret_value))
+            HGOTO_ERROR(H5E_INDEX, H5E_CANTCLOSEOBJ, FAIL, "cannot query index");
+    }
+    else 
+#endif
+    {
+        /* Brute force it */
+        size_t elmt_size=0, buf_size=0;
+        size_t nelmts;
+        H5VL__iod_get_query_data_t udata;
+
+        if((dset_space_id = H5Dget_space(dset_id)) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get space id from dataset");
+        if((type_id = H5Dget_type(dset_id)) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get space id from dataset");
+
+        if(space_id < 0) {
+            use_region_scope = FALSE;
+            space_id = dset_space_id;
+        }
+
+        nelmts = (size_t) H5Sget_select_npoints(space_id);
+        elmt_size = H5Tget_size(type_id);
+        buf_size = nelmts * elmt_size;
+
+        /* allocate buffer to hold data */
+        if(NULL == (buf = malloc(buf_size)))
+            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate data buffer");
+
+        FUNC_LEAVE_API_THREADSAFE;
+        ret_value = H5Dread_ff(dset_id, type_id, H5S_ALL, space_id, H5P_DEFAULT, 
+                               buf, rcxt_id, H5_EVENT_STACK_NULL);
+        FUNC_ENTER_API_THREADSAFE;
+
+        if(SUCCEED != ret_value)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't read data from dataset");
+
+        if(FAIL == (udata.space_query = H5Scopy(space_id)))
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOPY, NULL, "can't copy dataspace")
+        if(H5Sselect_none(udata.space_query) < 0)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTDELETE, FAIL, "can't change selection")
+
+        udata.query_id = query_id;
+        udata.num_elmts = 0;
+
+        /* iterate over every element and apply the query on it. If the
+           query is not satisfied, then remove it from the query selection */
+        if(H5Diterate(buf, type_id, space_id, H5VL__iod_get_query_data_cb, &udata) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "failed to apply query on Dataset")
+
+        ret_value = udata.space_query;
+    }
+
+done:
+    if(xxpl_id != FAIL && H5I_dec_app_ref(xxpl_id) < 0)
+            HDONE_ERROR(H5E_PLIST, H5E_CANTFREE, FAIL, "can't close plist");
+    if(space_id != FAIL && H5I_dec_app_ref(space_id) < 0)
+        HDONE_ERROR(H5E_DATASPACE, H5E_CANTFREE, FAIL, "can't close dataspace");
+    if(use_region_scope)
+        if(dset_space_id != FAIL && H5I_dec_app_ref(dset_space_id) < 0)
+            HDONE_ERROR(H5E_DATASPACE, H5E_CANTFREE, FAIL, "can't close dataspace");
+    if(type_id != FAIL && H5I_dec_app_ref(type_id) < 0)
+        HDONE_ERROR(H5E_DATATYPE, H5E_CANTFREE, FAIL, "can't close dataspace");
+
+    if(buf) {
+        free(buf);
+        buf = NULL;
+    }
+
+    FUNC_LEAVE_API(ret_value)
+}
 #endif /* H5_HAVE_EFF */
diff --git a/src/H5V.c b/src/H5V.c
index 630059f..6a893ac 100644
--- a/src/H5V.c
+++ b/src/H5V.c
@@ -308,10 +308,6 @@ H5Vcreate_ff(hid_t loc_id, hid_t query_id, hid_t vcpl_id, hid_t rcxt_id, hid_t e
     void    **req = NULL;       /* pointer to plugin generate requests (Stays NULL if plugin does not support async */
     void    *view = NULL;       /* pointer to view object created */
     void    *obj = NULL;        /* object token of loc_id */
-#ifdef H5_HAVE_INDEXING
-    void *idx_handle = NULL; /* index */
-#endif
-    hid_t dataspace_id = -1;
     H5VL_t  *vol_plugin;        /* VOL plugin information */
     hid_t ret_value;
 
@@ -346,36 +342,8 @@ H5Vcreate_ff(hid_t loc_id, hid_t query_id, hid_t vcpl_id, hid_t rcxt_id, hid_t e
         vol_plugin->nrefs ++;
     }
 
-#ifdef H5_HAVE_INDEXING
-    /* Try to get indexing info (only for one dataset now) */
-    if (H5I_object_verify(loc_id, H5I_DATASET) &&
-            (NULL != (idx_handle = H5VL_iod_dataset_get_index(obj)))) {
-        H5X_class_t *idx_class = NULL;
-        H5P_genplist_t *xxpl_plist; /* Property list pointer */
-        hid_t xxpl_id = H5P_INDEX_XFER_DEFAULT;
-        unsigned plugin_id;
-
-        if (!(plugin_id = H5VL_iod_dataset_get_index_plugin_id(obj)))
-            HGOTO_ERROR(H5E_INDEX, H5E_CANTGET, FAIL, "can't get index plugin ID from dataset");
-        if (NULL == (idx_class = H5X_registered(plugin_id)))
-            HGOTO_ERROR(H5E_INDEX, H5E_CANTGET, FAIL, "can't get index plugin class");
-
-        /* store the read context ID in the xxpl */
-        if (NULL == (xxpl_plist = (H5P_genplist_t *) H5I_object(xxpl_id)))
-            HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
-        if (H5P_set(xxpl_plist, H5VL_CONTEXT_ID, &rcxt_id) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans_id");
-
-        if (NULL == idx_class->query)
-            HGOTO_ERROR(H5E_INDEX, H5E_BADVALUE, FAIL, "plugin query callback is not defined");
-        if (FAIL == idx_class->query(idx_handle, query_id, xxpl_id, &dataspace_id))
-            HGOTO_ERROR(H5E_INDEX, H5E_CANTCLOSEOBJ, FAIL, "cannot close index");
-    }
-#endif
-
     /* call the IOD specific private routine to create a view object */
-    if(NULL == (view = H5VL_iod_view_create(obj, query_id, dataspace_id,
-                                            vcpl_id, rcxt_id, req)))
+    if(NULL == (view = H5VL_iod_view_create(obj, query_id, vcpl_id, rcxt_id, req)))
         HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create view")
 
     if(request && *req) {
@@ -388,11 +356,6 @@ H5Vcreate_ff(hid_t loc_id, hid_t query_id, hid_t vcpl_id, hid_t rcxt_id, hid_t e
 	HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to atomize view handle")
 
 done:
-    if(dataspace_id != -1) {
-        if(H5I_dec_ref(dataspace_id) < 0)
-            HDONE_ERROR(H5E_SYM, H5E_CLOSEERROR, FAIL, "unable to release dataspace")
-    }
-
     if (ret_value < 0 && view) {
         if(H5V_close (view) < 0)
             HDONE_ERROR(H5E_SYM, H5E_CLOSEERROR, FAIL, "unable to release view")
diff --git a/src/H5VLiod.c b/src/H5VLiod.c
index c7bfc9c..344cf5c 100644
--- a/src/H5VLiod.c
+++ b/src/H5VLiod.c
@@ -6369,7 +6369,7 @@ H5VL_iod_obj_open_token(const void *token, H5TR_t *tr, H5I_type_t *opened_type,
         dset->common.obj_name = NULL;
 
 #if H5_EFF_DEBUG
-        printf("Dataset open by token %"PRIu64": ID %"PRIu64"\n", 
+        printf("Dataset open by token %"PRIu64": ID %"PRIx64"\n", 
                g_axe_id, input.iod_id);
 #endif
 
@@ -10227,11 +10227,11 @@ done:
  *-------------------------------------------------------------------------
  */
 void *
-H5VL_iod_view_create(void *_obj, hid_t query_id, hid_t dataspace_id,
-                     hid_t vcpl_id, hid_t rcxt_id, void **req)
+H5VL_iod_view_create(void *_obj, hid_t query_id, hid_t vcpl_id, hid_t rcxt_id, void **req)
 {
     H5VL_iod_object_t *obj = (H5VL_iod_object_t *)_obj; /* location object to create the view */
     H5VL_iod_view_t *view = NULL; /* the view object that is created and passed to the user */
+    view_create_in_t input;
     iod_obj_id_t iod_id, mdkv_id, attrkv_id;
     iod_handles_t iod_oh;
     H5VL_iod_request_t **parent_reqs = NULL;
@@ -10305,52 +10305,33 @@ H5VL_iod_view_create(void *_obj, hid_t query_id, hid_t dataspace_id,
            iod_id, g_axe_id);
 #endif
 
-    /* If we already have a dataspace id, no need to ship */
-    if (dataspace_id != -1) {
-        view->remote_view.attr_info.count = 0;
-        view->remote_view.attr_info.tokens = NULL;
-        view->remote_view.obj_info.count = 0;
-        view->remote_view.obj_info.tokens = NULL;
-        view->remote_view.region_info.count = 0;
-//        view->remote_view.region_info.regions = H5MM_malloc(sizeof(hid_t));
-//        view->remote_view.region_info.regions[0] = H5Scopy(dataspace_id);
-//        H5Sclose(dataspace_id);
-        /* TODO fix that */
-        view->remote_view.region_info.tokens = NULL;
-        view->remote_view.region_info.regions = NULL;
-
-        view->remote_view.valid_view = TRUE;
-    } else {
-        view_create_in_t input;
-
-        /* Initialize the view types to be obtained from server */
-        view->remote_view.attr_info.count = 0;
-        view->remote_view.attr_info.tokens = NULL;
-        view->remote_view.obj_info.count = 0;
-        view->remote_view.obj_info.tokens = NULL;
-        view->remote_view.region_info.count = 0;
-        view->remote_view.region_info.tokens = NULL;
-        view->remote_view.region_info.regions = NULL;
-        view->remote_view.valid_view = FALSE;
+    /* Initialize the view types to be obtained from server */
+    view->remote_view.attr_info.count = 0;
+    view->remote_view.attr_info.tokens = NULL;
+    view->remote_view.obj_info.count = 0;
+    view->remote_view.obj_info.tokens = NULL;
+    view->remote_view.region_info.count = 0;
+    view->remote_view.region_info.tokens = NULL;
+    view->remote_view.region_info.regions = NULL;
+    view->remote_view.valid_view = FALSE;
 
-        /* set the input structure for the HG encode routine */
-        input.coh = obj->file->remote_file.coh;
-        input.loc_id = iod_id;
-        input.loc_oh = iod_oh;
-        input.loc_mdkv_id = mdkv_id;
-        input.loc_attrkv_id = attrkv_id;
-        input.query_id = query_id;
-        input.vcpl_id = vcpl_id;
-        input.obj_type = obj->obj_type;
-        input.rcxt_num  = rc->c_version;
-        input.cs_scope = obj->file->md_integrity_scope;
-
-        if(H5VL__iod_create_and_forward(H5VL_VIEW_CREATE_ID, HG_VIEW_CREATE,
-                (H5VL_iod_object_t *)view, 1, num_parents, parent_reqs,
-                (H5VL_iod_req_info_t *)rc, &input, &view->remote_view,
-                view, req) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship view create");
-    }
+    /* set the input structure for the HG encode routine */
+    input.coh = obj->file->remote_file.coh;
+    input.loc_id = iod_id;
+    input.loc_oh = iod_oh;
+    input.loc_mdkv_id = mdkv_id;
+    input.loc_attrkv_id = attrkv_id;
+    input.query_id = query_id;
+    input.vcpl_id = vcpl_id;
+    input.obj_type = obj->obj_type;
+    input.rcxt_num  = rc->c_version;
+    input.cs_scope = obj->file->md_integrity_scope;
+
+    if(H5VL__iod_create_and_forward(H5VL_VIEW_CREATE_ID, HG_VIEW_CREATE,
+                                    (H5VL_iod_object_t *)view, 1, num_parents, parent_reqs,
+                                    (H5VL_iod_req_info_t *)rc, &input, &view->remote_view,
+                                    view, req) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "failed to create and ship view create");
 
     ret_value = (void *)view;
 
diff --git a/src/H5VLiod.h b/src/H5VLiod.h
index 04651b8..6f08062 100644
--- a/src/H5VLiod.h
+++ b/src/H5VLiod.h
@@ -100,6 +100,7 @@ H5_DLL herr_t H5Pget_dcpl_append_only(hid_t dcpl_id, hbool_t *flag);
 
 H5_DLL hid_t H5VLiod_get_file_id(const char *filename, iod_handle_t coh, hid_t fapl_id, hid_t *rcxt_id);
 H5_DLL herr_t H5VLiod_close_file_id(hid_t file_id);
+H5_DLL hid_t H5Dquery_ff(hid_t dset_id, hid_t query_id, hid_t scope_id, hid_t rcxt_id);
 
 #endif /* H5_HAVE_EFF */
 
diff --git a/src/H5VLiod_analysis.c b/src/H5VLiod_analysis.c
index 2b01eeb..80d952e 100644
--- a/src/H5VLiod_analysis.c
+++ b/src/H5VLiod_analysis.c
@@ -1194,42 +1194,6 @@ done:
 } /* end H5VL__iod_get_space_layout() */
 
 /*-------------------------------------------------------------------------
- * Function:    H5VL__iod_get_query_data_cb
- *
- *
- * Return:	Success:	SUCCEED 
- *		Failure:	Negative
- *
- *-------------------------------------------------------------------------
- */
-herr_t 
-H5VL__iod_get_query_data_cb(void *elem, hid_t type_id, unsigned ndim, 
-                            const hsize_t *point, void *_udata)
-{
-    H5VL__iod_get_query_data_t *udata = (H5VL__iod_get_query_data_t *)_udata;
-    hbool_t result;
-    herr_t ret_value = SUCCEED;
-
-    /* Apply the query */
-    if(H5Qapply(udata->query_id, &result, type_id, elem) < 0)
-        HGOTO_ERROR_FF(FAIL, "unable to apply query to data element");
-
-    /* If element satisfies query, add it to the selection */
-    if (result) {
-        /* TODO remove that after demo */
-#if 0
-        fprintf(stderr, "(%d) Element |%d| matches query\n", my_rank_g, *((int *) elem));
-#endif
-        udata->num_elmts ++;
-        if(H5Sselect_elements(udata->space_query, H5S_SELECT_APPEND, 1, point) < 0)
-            HGOTO_ERROR_FF(FAIL, "unable to add point to selection")
-    }
-
-done:
-    return ret_value;
-} /* end H5VL__iod_get_query_data_cb */
-
-/*-------------------------------------------------------------------------
  * Function:    H5VL__iod_get_query_data
  *
  * Purpose:     Generates a dataspace from the query specified. The dataspace 
diff --git a/src/H5VLiod_client.c b/src/H5VLiod_client.c
index b76ecf8..8108f3d 100644
--- a/src/H5VLiod_client.c
+++ b/src/H5VLiod_client.c
@@ -221,6 +221,7 @@ H5VL_iod_request_wait(H5VL_iod_file_t *file, H5VL_iod_request_t *request)
        container to avoid deadlock. */
     while(1) {
         HDassert(request->state == H5VL_IOD_PENDING);
+
         /* test the operation status */
         FUNC_LEAVE_API_THREADSAFE;
         ret = HG_Wait(*((hg_request_t *)request->req), 0, &status);
diff --git a/src/H5VLiod_client.h b/src/H5VLiod_client.h
index 23de9b2..e04871c 100644
--- a/src/H5VLiod_client.h
+++ b/src/H5VLiod_client.h
@@ -490,8 +490,8 @@ H5_DLL herr_t H5VL_iod_prefetch(void *obj, hid_t rcxt_id, hrpl_t *replica_id,
                                 hid_t apl_id, void **req);
 H5_DLL herr_t H5VL_iod_evict(void *obj, uint64_t c_version, hid_t apl_id, void **req);
 
-H5_DLL void * H5VL_iod_view_create(void *_obj, hid_t query_id, hid_t dataspace_id,
-        hid_t vcpl_id, hid_t rcxt_id, void **req);
+H5_DLL void * H5VL_iod_view_create(void *_obj, hid_t query_id, hid_t vcpl_id, 
+                                   hid_t rcxt_id, void **req);
 H5_DLL herr_t H5VL_iod_view_close(H5VL_iod_view_t *view);
 
 H5_DLL herr_t H5VL_iod_analysis_execute(const char *file_name, const char *obj_name,
diff --git a/src/H5VLiod_dset.c b/src/H5VLiod_dset.c
index 517961a..7a59ca7 100644
--- a/src/H5VLiod_dset.c
+++ b/src/H5VLiod_dset.c
@@ -653,7 +653,7 @@ H5VL_iod_server_dset_read_cb(AXE_engine_t axe_engine,
                                                HG_BULK_READWRITE, &bulk_block_handle))
             HGOTO_ERROR_FF(FAIL, "can't create bulk handle");
     }
-    
+
     /*
     if(H5VL__iod_server_adjust_buffer(dst_id, src_id, nelmts, dxpl_id, is_coresident,
                                       size, &buf, &is_vl_data, &buf_size) < 0)
diff --git a/src/H5VLiod_view.c b/src/H5VLiod_view.c
index 0ee7909..951c823 100644
--- a/src/H5VLiod_view.c
+++ b/src/H5VLiod_view.c
@@ -24,6 +24,8 @@
 #include "H5VLiod_server.h"
 
 #include "H5Qpublic.h"
+#include "H5RCpublic.h"
+#include "H5TRpublic.h"
 #include "H5Vpublic.h"
 
 #ifdef H5_HAVE_EFF
@@ -55,6 +57,8 @@ typedef struct {
 typedef struct {
     hid_t query_id;
     hid_t vcpl_id;
+    hid_t file_id;
+    hid_t rcxt_id;
     H5VL_iod_view_obj_t *view;
 } H5VL_build_view_t;
 
@@ -69,7 +73,8 @@ static herr_t
 H5VL__iod_get_token(iod_handle_t coh, H5I_type_t obj_type, iod_obj_id_t iod_id, 
                     iod_trans_id_t rtid, uint32_t cs_scope, size_t *_token_size, void **_token);
 static herr_t 
-H5VL__iod_apply_query(hid_t qid, hid_t vcpl_id, iod_handle_t coh, iod_obj_id_t obj_id, 
+H5VL__iod_apply_query(hid_t file_id, hid_t rcxt_id, hid_t qid, hid_t vcpl_id, 
+                      iod_handle_t coh, iod_obj_id_t obj_id, 
                       iod_trans_id_t rtid, H5I_type_t obj_type, 
                       const char *link_name, const char *attr_name,
                       size_t num_attrs, char *attr_list[],
@@ -122,12 +127,20 @@ H5VL_iod_server_view_create_cb(AXE_engine_t UNUSED axe_engine,
     H5VL_build_view_t udata;
     H5VL_iod_view_entry_t *entry = NULL;
     H5VL_iod_view_obj_t *view = NULL;
+    hid_t file_id, rcxt_id, fapl_id;
     herr_t ret_value = SUCCEED;
 
 #if H5_EFF_DEBUG 
     fprintf(stderr, "Start View create on OID %"PRIx64"\n", loc_id);
 #endif
 
+    /* wrap a file hid_t around the iod container handle */
+    fapl_id = H5Pcreate (H5P_FILE_ACCESS);
+    H5Pset_fapl_iod(fapl_id, MPI_COMM_SELF, MPI_INFO_NULL);
+    if((file_id = H5VLiod_get_file_id("bla", coh, fapl_id, &rcxt_id)) < 0)
+        HGOTO_ERROR_FF(FAIL, "can't get file ID");
+    H5Pclose(fapl_id);
+
     if(H5P_DEFAULT == input->vcpl_id)
         input->vcpl_id = H5Pcopy(H5P_VIEW_CREATE_DEFAULT);
     vcpl_id = input->vcpl_id;
@@ -137,6 +150,8 @@ H5VL_iod_server_view_create_cb(AXE_engine_t UNUSED axe_engine,
     udata.view = view;
     udata.query_id = query_id;
     udata.vcpl_id = vcpl_id;
+    udata.file_id = file_id;
+    udata.rcxt_id = rcxt_id;
 
     if(H5VL_iod_server_iterate(coh, loc_id, rtid, obj_type, NULL, NULL, cs_scope, 
                                H5VL__iod_build_view_cb, &udata) < 0)
@@ -199,6 +214,13 @@ H5VL_iod_server_view_create_cb(AXE_engine_t UNUSED axe_engine,
         }
     }
 
+    /* free the file ID and release the read context */
+    if(H5RCrelease(rcxt_id, H5_EVENT_STACK_NULL) < 0)
+        HGOTO_ERROR_FF(FAIL, "can't release read context");
+    H5RCclose(rcxt_id);
+    if(H5VLiod_close_file_id(file_id) < 0)
+        HGOTO_ERROR_FF(FAIL, "can't release file id");
+
 done:
 
 #if H5_EFF_DEBUG 
@@ -352,7 +374,8 @@ H5VL__iod_build_view_cb(iod_handle_t coh, iod_obj_id_t obj_id, iod_trans_id_t rt
             HGOTO_ERROR_FF(ret, "can't close object");
     }
 
-    ret = H5VL__iod_apply_query(op_data->query_id, op_data->vcpl_id, 
+    ret = H5VL__iod_apply_query(op_data->file_id, op_data->rcxt_id, 
+                                op_data->query_id, op_data->vcpl_id, 
                                 coh, obj_id, rtid, obj_type, 
                                 link_name, attr_name, (size_t)num_attrs, attr_list, 
                                 cs_scope, &result, &region);
@@ -394,7 +417,8 @@ done:
 }
 
 static herr_t 
-H5VL__iod_apply_query(hid_t qid, hid_t vcpl_id, iod_handle_t coh, iod_obj_id_t obj_id, 
+H5VL__iod_apply_query(hid_t file_id, hid_t rcxt_id, hid_t qid, hid_t vcpl_id,
+                      iod_handle_t coh, iod_obj_id_t obj_id, 
                       iod_trans_id_t rtid, H5I_type_t obj_type, 
                       const char *link_name, const char *attr_name,
                       size_t num_attrs, char *attr_list[],
@@ -417,11 +441,39 @@ H5VL__iod_apply_query(hid_t qid, hid_t vcpl_id, iod_handle_t coh, iod_obj_id_t o
 
         if(H5Q_TYPE_DATA_ELEM == q_type) {
             if(H5I_DATASET == obj_type) {
-                hid_t sid;
+                hid_t sid, scope_id;
+                hid_t dset_id, trans_id;
+                size_t token_size = 0;
+                void *token = NULL;
+
+                if(H5VL__iod_get_token(coh, obj_type, obj_id, rtid, cs_scope,
+                                       &token_size, &token) < 0)
+                    HGOTO_ERROR_FF(FAIL, "failed to get object token");
+
+                trans_id = H5TRcreate(file_id, rcxt_id, rtid);
+                if((dset_id = H5Oopen_by_token(token, trans_id, H5_EVENT_STACK_NULL)) < 0)
+                    HGOTO_ERROR_FF(FAIL, "failed to open dataset by token");
+                H5TRclose(trans_id);
+
+                /* Check if VCPL has a dataspace specified; otherwise, read the entire dataset. */
+                if(H5Pget_view_elmt_scope(vcpl_id, &scope_id) < 0)
+                    HGOTO_ERROR_FF(FAIL, "can't retrieve vcpl region scope");
+
+                sid = H5Dquery_ff(dset_id, qid, scope_id, rcxt_id);
+                if(FAIL == sid)
+                    HGOTO_ERROR_FF(FAIL, "failed to apply query on dataset region");
+
+                if(H5Dclose_ff(dset_id, H5_EVENT_STACK_NULL) < 0)
+                    HGOTO_ERROR_FF(FAIL, "failed to close dataset");
+
+                if(token) {
+                    free(token);
+                    token = NULL;
+                }
 
                 /* add object to view with region if region is not NONE */
-                if((sid = H5VL__iod_get_elmt_region(coh, obj_id, rtid, qid, vcpl_id, cs_scope)) < 0)
-                    HGOTO_ERROR_FF(FAIL, "can't get region from query");
+                //if((sid = H5VL__iod_get_elmt_region(coh, obj_id, rtid, qid, vcpl_id, cs_scope)) < 0)
+                //HGOTO_ERROR_FF(FAIL, "can't get region from query");
 
                 fprintf(stderr, "Found %zu Entries in subquery\n", H5Sget_select_npoints(sid));
                 if(H5Sget_select_npoints(sid) > 0) {
@@ -493,7 +545,7 @@ H5VL__iod_apply_query(hid_t qid, hid_t vcpl_id, iod_handle_t coh, iod_obj_id_t o
         if(H5Qget_components(qid, &qid1, &qid2) < 0)
             HGOTO_ERROR_FF(FAIL, "can't get query components");
 
-        ret = H5VL__iod_apply_query(qid1, vcpl_id, coh, obj_id, rtid, 
+        ret = H5VL__iod_apply_query(file_id, rcxt_id, qid1, vcpl_id, coh, obj_id, rtid, 
                                     obj_type, link_name, attr_name, 
                                     num_attrs, attr_list, cs_scope, 
                                     &result1, &sid1);
@@ -506,7 +558,7 @@ H5VL__iod_apply_query(hid_t qid, hid_t vcpl_id, iod_handle_t coh, iod_obj_id_t o
             *result = QFALSE;
         }
         else {
-            ret = H5VL__iod_apply_query(qid2, vcpl_id, coh, obj_id, rtid, 
+            ret = H5VL__iod_apply_query(file_id, rcxt_id, qid2, vcpl_id, coh, obj_id, rtid, 
                                         obj_type, link_name, attr_name, 
                                         num_attrs, attr_list, cs_scope, 
                                         &result2, &sid2);
@@ -875,7 +927,7 @@ H5VL__iod_get_elmt_region(iod_handle_t coh, iod_obj_id_t dset_id, iod_trans_id_t
 
     /* Check if VCPL has a dataspace specified; otherwise, read the entire dataset. */
     if(H5Pget_view_elmt_scope(vcpl_id, &space_id) < 0)
-        HGOTO_ERROR_FF(FAIL, "can't retrieve vcpl region scope");;
+        HGOTO_ERROR_FF(FAIL, "can't retrieve vcpl region scope");
 
     /* open the array object */
     if(iod_obj_open_read(coh, dset_id, rtid, NULL, &dset_oh, NULL) < 0)
@@ -922,7 +974,6 @@ H5VL__iod_get_elmt_region(iod_handle_t coh, iod_obj_id_t dset_id, iod_trans_id_t
         HGOTO_ERROR_FF(FAIL, "can't allocate read buffer");
 
     /* read the data selection from IOD. */
-    elmt_size = H5Tget_size(type_id);
     if(H5VL__iod_server_final_io(dset_oh, space_id, elmt_size, FALSE, 
                                  buf, buf_size, (uint64_t)0, 0, rtid) < 0)
         HGOTO_ERROR_FF(FAIL, "can't read from array object");
@@ -961,6 +1012,41 @@ done:
     return ret_value;
 } /* end H5VL__iod_get_elmt_region() */
 
+/*-------------------------------------------------------------------------
+ * Function:    H5VL__iod_get_query_data_cb
+ *
+ *
+ * Return:	Success:	SUCCEED 
+ *		Failure:	Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t 
+H5VL__iod_get_query_data_cb(void *elem, hid_t type_id, unsigned ndim, 
+                            const hsize_t *point, void *_udata)
+{
+    H5VL__iod_get_query_data_t *udata = (H5VL__iod_get_query_data_t *)_udata;
+    hbool_t result;
+    herr_t ret_value = SUCCEED;
+
+    /* Apply the query */
+    if(H5Qapply(udata->query_id, &result, type_id, elem) < 0)
+        HGOTO_ERROR_FF(FAIL, "unable to apply query to data element");
+
+    /* If element satisfies query, add it to the selection */
+    if (result) {
+#if 0
+        fprintf(stderr, "(%d) Element |%d| matches query\n", my_rank_g, *((int *) elem));
+#endif
+        udata->num_elmts ++;
+        if(H5Sselect_elements(udata->space_query, H5S_SELECT_APPEND, 1, point) < 0)
+            HGOTO_ERROR_FF(FAIL, "unable to add point to selection")
+    }
+
+done:
+    return ret_value;
+} /* end H5VL__iod_get_query_data_cb */
+
 static void
 H5VL__iod_add_entry(H5VL_iod_view_list_t *list, H5VL_iod_view_entry_t* entry)
 {