Simplify the PMIx_get processing:

If the key starts with “pmix”, then it is a PMIx-namespace key and can only be in the data provided at startup (which is stored in the “internal" hash table). Otherwise, it is data that was PMix_Put and is in the “modex” hash table. PMIx job-level data is stored in the “internal” hash table against rank=PMIX_RANK_WILDCARD.

This reduces all calls to PMIx_Get to a single hash-table lookup

src/client/pmix_client_get.c

@@ -409,10 +409,11 @@ static void _getnbfn(int fd, short flags, void *cbdata)
          goto request;
     }
 
-    /* if the key is NULL, then we have to check both the job-data
-     * and the modex tables. If we don't yet have the modex data,
-     * then we are going to have to go get it. So let's check that
-     * case first */
+    /* The NULL==key scenario only pertains to cases where legacy
+     * PMI methods are being employed. In this case, we have to check
+     * both the job-data  and the modex tables. If we don't yet have
+     * the modex data, then we are going to have to go get it. So let's
+     * check that case first */
     if (NULL == cb->key) {
         PMIX_CONSTRUCT(&results, pmix_pointer_array_t);
         pmix_pointer_array_init(&results, 2, INT_MAX, 1);
@@ -451,9 +452,7 @@ static void _getnbfn(int fd, short flags, void *cbdata)
                 }
             } else {
                 /* if we didn't find a modex for this rank, then we need
-                 * to go get it. Recall that the NULL==key scenario only
-                 * pertains to cases where legacy PMI methods are being
-                 * employed. Thus, the caller wants -all- information for
+                 * to go get it. Thus, the caller wants -all- information for
                  * the specified rank, not just the job-level info. */
                  goto request;
             }
@@ -505,43 +504,28 @@ static void _getnbfn(int fd, short flags, void *cbdata)
         return;
     }
 
-    /* the requested data could be in the job-data table, so let's
-     * just check there first.  */
-    if (PMIX_SUCCESS == (rc = pmix_hash_fetch(&nptr->internal, PMIX_RANK_WILDCARD, cb->key, &val))) {
-        /* found it - we are in an event, so we can
-         * just execute the callback */
-        cb->value_cbfunc(rc, val, cb->cbdata);
-        /* cleanup */
-        if (NULL != val) {
-            PMIX_VALUE_RELEASE(val);
+    /* if the key is in the PMIx namespace, then they are looking for data
+     * that was provided at startup */
+    if (0 == strncmp(cb->key, "pmix", 4)) {
+        /* should be in the internal hash table. */
+        if (PMIX_SUCCESS == (rc = pmix_hash_fetch(&nptr->internal, cb->rank, cb->key, &val))) {
+            /* found it - we are in an event, so we can
+             * just execute the callback */
+            cb->value_cbfunc(rc, val, cb->cbdata);
+            /* cleanup */
+            if (NULL != val) {
+                PMIX_VALUE_RELEASE(val);
+            }
+            PMIX_RELEASE(cb);
+            return;
         }
-        PMIX_RELEASE(cb);
-        return;
-    }
-    if (PMIX_RANK_WILDCARD == cb->rank) {
         /* can't be anywhere else */
         cb->value_cbfunc(PMIX_ERR_NOT_FOUND, NULL, cb->cbdata);
         PMIX_RELEASE(cb);
         return;
     }
 
-    /* it could still be in the job-data table, only stored under its own
-     * rank and not WILDCARD - e.g., this is true of data returned about
-     * ourselves during startup */
-    if (PMIX_SUCCESS == (rc = pmix_hash_fetch(&nptr->internal, cb->rank, cb->key, &val))) {
-        /* found it - we are in an event, so we can
-         * just execute the callback */
-        cb->value_cbfunc(rc, val, cb->cbdata);
-        /* cleanup */
-        if (NULL != val) {
-            PMIX_VALUE_RELEASE(val);
-        }
-        PMIX_RELEASE(cb);
-        return;
-    }
-
-    /* not finding it is not an error - it could be in the
-     * modex hash table, so check it */
+    /* otherwise, the data must be something they "put" */
 #if defined(PMIX_ENABLE_DSTORE) && (PMIX_ENABLE_DSTORE == 1)
     if (PMIX_SUCCESS == (rc = pmix_dstore_fetch(nptr->nspace, cb->rank, cb->key, &val))) {
 #else