Also handle streams not written to by collector.

src/pio_server.c

@@ -489,6 +489,7 @@ inventorizeStream(struct streamMapping *streamMap, int numStreamIDs,
     }
   streamMap[numStreamIDs].streamID = streamID;
   streamMap[numStreamIDs].firstHeaderIdx = headerIdx;
+  streamMap[numStreamIDs].lastHeaderIdx = headerIdx;
   streamMap[numStreamIDs].numVars = -1;
   int filetype = streamInqFiletype(streamID);
   streamMap[numStreamIDs].filetype = filetype;
@@ -507,6 +508,16 @@ inventorizeStream(struct streamMapping *streamMap, int numStreamIDs,
   return numStreamIDs + 1;
 }
 
+static inline int
+streamIsInList(struct streamMapping *streamMap, int numStreamIDs,
+               int streamIDQuery)
+{
+  int p = 0;
+  for (int i = 0; i < numStreamIDs; ++i)
+    p |= streamMap[i].streamID == streamIDQuery;
+  return p;
+}
+
 static struct streamMap
 buildStreamMap(union winHeaderEntry *winDict)
 {
@@ -514,9 +525,11 @@ buildStreamMap(union winHeaderEntry *winDict)
   int oldStreamIdx = CDI_UNDEFID;
   int filetype = CDI_UNDEFID;
   int sizeStreamMap = 16;
-  struct streamMapping *streamMap = xmalloc(sizeStreamMap * sizeof (streamMap[0]));
+  struct streamMapping *streamMap
+    = xmalloc(sizeStreamMap * sizeof (streamMap[0]));
   int numDataEntries = winDict[0].headerSize.numDataEntries;
   int numStreamIDs = 0;
+  /* find streams written on this process */
   for (int headerIdx = 1; headerIdx < numDataEntries; headerIdx += 2)
     {
       int streamID
@@ -546,6 +559,28 @@ buildStreamMap(union winHeaderEntry *winDict)
           streamMap[oldStreamIdx].varMap[varID] = headerIdx;
         }
     }
+  /* join with list of streams written to in total */
+  {
+    int *streamIDs, *streamIsWritten;
+    int numTotalStreamIDs = streamSize();
+    streamIDs = xmalloc(2 * sizeof (streamIDs[0]) * (size_t)numTotalStreamIDs);
+    streamGetIndexList(numTotalStreamIDs, streamIDs);
+    streamIsWritten = streamIDs + numTotalStreamIDs;
+    for (int i = 0; i < numTotalStreamIDs; ++i)
+      streamIsWritten[i] = streamIsInList(streamMap, numStreamIDs,
+                                          streamIDs[i]);
+    /* Find what streams are written to at all on any process */
+    xmpi(MPI_Allreduce(MPI_IN_PLACE, streamIsWritten, numTotalStreamIDs,
+                       MPI_INT, MPI_BOR, commInqCommColl()));
+    /* append streams written to on other tasks to mapping */
+    for (int i = 0; i < numTotalStreamIDs; ++i)
+      if (streamIsWritten[i] && !streamIsInList(streamMap, numStreamIDs,
+                                                streamIDs[i]))
+        numStreamIDs = inventorizeStream(streamMap, numStreamIDs,
+                                         &sizeStreamMap, streamIDs[i], -1);
+
+    free(streamIDs);
+  }
   return (struct streamMap){ .entries = streamMap, .numEntries = numStreamIDs };
 }
 
@@ -602,6 +637,8 @@ static void readGetBuffers()
           case FILETYPE_GRB2:
             {
               int headerIdx, lastHeaderIdx = map.entries[streamIdx].lastHeaderIdx;
+              if (lastHeaderIdx < 0)
+                break;
               for (headerIdx = map.entries[streamIdx].firstHeaderIdx;
                    headerIdx <= lastHeaderIdx;
                    headerIdx += 2)