[svn-r7552] Purpose:

    Bug/feature fix.

Description:
    Relax restriction on parallel writing to compact datasets to allow partial
I/O.

    Updated reference manual mentioning the issues involved.

Platforms tested:
    FreeBSD 4.9 (sleipnir)
    too minor to require h5committest

5 files changed, 19 insertions, 33 deletions

diff --git a/doc/html/RM_H5D.html b/doc/html/RM_H5D.html
index 0d30cc7..17505db 100644
--- a/doc/html/RM_H5D.html
+++ b/doc/html/RM_H5D.html
@@ -1197,6 +1197,12 @@ facilitate moving easily between them.</i>
 	<a href="RM_H5P.html#Property-SetFillTime">H5Pset_fill_time</a>
 	and 
 	<a href="RM_H5P.html#Property-SetAllocTime">H5Pset_alloc_time</a>.)
+        <p>
+        If a dataset's storage layout is 'compact', care must be taken when
+        writing data to the dataset in parallel.  A compact dataset's raw data
+        is cached in memory and may be flushed to the file from any of the
+        parallel processes, so parallel applications should always attempt to
+        write identical data to the dataset from all processes.
 	
 <dt><strong>Parameters:</strong>
     <dl>
diff --git a/doc/html/RM_H5P.html b/doc/html/RM_H5P.html
index e7e377b..cc3cdcb 100644
--- a/doc/html/RM_H5P.html
+++ b/doc/html/RM_H5P.html
@@ -2889,6 +2889,11 @@ facilitate moving easily between them.</i>
     <dd><code>H5Pget_layout</code> returns the layout of the raw data for 
         a dataset.  This function is only valid for dataset creation 
         property lists.  
+        <p>
+        Note that a compact storage layout may affect writing data to
+        the dataset with parallel applications.  See note in
+	<a href="RM_H5D.html#Dataset-Write">H5Dwrite</a>
+        documentation for details.
 	
   <dt><strong>Parameters:</strong>
     <dl>
@@ -6651,6 +6656,11 @@ fid=H5Fcreate("PointA",H5F_ACC_TRUNC,H5P_DEFAULT,fapl);
                     <dd>Store raw data separately from the object header as 
                         chunks of data in separate locations in the file.
             </dl></ul>
+        <p>
+        Note that a compact storage layout may affect writing data to
+        the dataset with parallel applications.  See note in
+	<a href="RM_H5D.html#Dataset-Write">H5Dwrite</a>
+        documentation for details.
   <dt><strong>Parameters:</strong>
     <dl>
         <dt><em>hid_t</em> <code>plist</code>
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index 7a76661..bc7830d 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -56,6 +56,7 @@ Bug Fixes since HDF5-1.6.0 release
 
     Library
     -------
+        - Allow partial parallel writing to compact datasets.  QAK - 2003/10/06
         - Correctly create reference to shared datatype in attribute, instead
             of making a copy of the shared datatype in the attribute.
             QAK - 2003/10/01
diff --git a/src/H5Dio.c b/src/H5Dio.c
index 944825f..e03fc7f 100644
--- a/src/H5Dio.c
+++ b/src/H5Dio.c
@@ -792,14 +792,6 @@ H5D_write(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
             !(IS_H5FD_MPIO(dataset->ent.file) || IS_H5FD_MPIPOSIX(dataset->ent.file) || IS_H5FD_FPHDF5(dataset->ent.file)))
         HGOTO_ERROR (H5E_DATASET, H5E_UNSUPPORTED, FAIL, "collective access for MPIO driver only");
 
-    /* If dataset is compact, collective access is only allowed when file space
-     * selection is H5S_ALL */
-    if(doing_mpio && xfer_mode==H5FD_MPIO_COLLECTIVE
-            && dataset->layout.type==H5D_COMPACT) { 
-        if(H5S_get_select_type(file_space) != H5S_SEL_ALL)    
-            HGOTO_ERROR (H5E_DATASET, H5E_UNSUPPORTED, FAIL, "collective access to compact dataset doesn't support partial access");        
-    }
-    
     /* Set the "parallel I/O possible" flag, for H5S_find() */
     if (H5S_mpi_opt_types_g && IS_H5FD_MPIO(dataset->ent.file)) {
 	/* Only collective write should call this since it eventually
diff --git a/testpar/t_mdset.c b/testpar/t_mdset.c
index 3d40307..5dfeb3b 100644
--- a/testpar/t_mdset.c
+++ b/testpar/t_mdset.c
@@ -105,16 +105,13 @@ void multiple_dset_write(char *filename, int ndatasets)
 }
 
 /* Example of using PHDF5 to create, write, and read compact dataset.  
- * Hyperslab is prohibited for write.
  */
 void compact_dataset(char *filename)
 {
     int i, j, mpi_size, mpi_rank, err_num=0;
     hbool_t use_gpfs = FALSE;
-    hid_t iof, plist, dcpl, dxpl, dataset, memspace, filespace;
-    hssize_t chunk_origin [DIM];
-    hsize_t chunk_dims [DIM], file_dims [DIM];
-    hsize_t count[DIM]={1,1};
+    hid_t iof, plist, dcpl, dxpl, dataset, filespace;
+    hsize_t file_dims [DIM]={SIZE,SIZE};
     double outme [SIZE][SIZE], inme[SIZE][SIZE];
     char dname[]="dataset";
     herr_t ret;
@@ -127,11 +124,7 @@ void compact_dataset(char *filename)
     plist = create_faccess_plist(MPI_COMM_WORLD, MPI_INFO_NULL, facc_type, use_gpfs);
     iof = H5Fcreate (filename, H5F_ACC_TRUNC, H5P_DEFAULT, plist);
 
-    /* decide the hyperslab according to process number. */
-    get_slab(chunk_origin, chunk_dims, count, file_dims);  
-
     /* Define data space */
-    memspace = H5Screate_simple (DIM, chunk_dims, NULL);
     filespace = H5Screate_simple (DIM, file_dims, NULL);
 
     /* Create a compact dataset */
@@ -145,27 +138,12 @@ void compact_dataset(char *filename)
     dataset = H5Dcreate (iof, dname, H5T_NATIVE_DOUBLE, filespace, dcpl);
     VRFY((dataset >= 0), "H5Dcreate succeeded");        
 
-    /* Define hyperslab */
-    ret = H5Sselect_hyperslab (filespace, H5S_SELECT_SET, chunk_origin, chunk_dims, count, chunk_dims);    
-    VRFY((ret>=0), "mdata hyperslab selection");
-    
     /* set up the collective transfer properties list */
     dxpl = H5Pcreate (H5P_DATASET_XFER);
     VRFY((dxpl >= 0), "");
     ret=H5Pset_dxpl_mpio(dxpl, H5FD_MPIO_COLLECTIVE);
     VRFY((ret >= 0), "H5Pcreate xfer succeeded");
 
-    /* calculate data to write */
-    for (i = 0; i < SIZE; i++)
-         for (j = 0; j < SIZE; j++)
-              outme [i][j] = (i+j)*1000 + mpi_rank;
-
-    /* Test hyperslab writing.  Supposed to fail */
-    H5E_BEGIN_TRY {
-        ret=H5Dwrite(dataset, H5T_NATIVE_DOUBLE, memspace, filespace, dxpl, outme);
-    } H5E_END_TRY;
-    VRFY((ret < 0), "H5Dwrite hyperslab write failed as expected");
-
     /* Recalculate data to write.  Each process writes the same data. */
     for (i = 0; i < SIZE; i++)
          for (j = 0; j < SIZE; j++)
@@ -178,7 +156,6 @@ void compact_dataset(char *filename)
     H5Pclose (plist);
     H5Dclose (dataset);
     H5Sclose (filespace);
-    H5Sclose (memspace);
     H5Fclose (iof);
 
     /* Open the file and dataset, read and compare the data. */