Improve HJDEBUG code a bit.

Commit 30d7ae3c76d2de144232ae6ab328ca86b70e72c3 introduced an HJDEBUG
stanza that probably didn't compile at the time, and definitely doesn't
compile now, because it refers to a nonexistent variable.  It doesn't seem
terribly useful anyway, so just get rid of it.

While I'm fooling with it, use %z modifier instead of the obsolete hack of
casting size_t to unsigned long, and include the HashJoinTable's address in
each printout so that it's possible to distinguish the activities of
multiple hashjoins occurring in one query.

Noted while trying to use HJDEBUG to investigate bug #13908.  Back-patch
to 9.5, because code that doesn't compile is certainly not very helpful.

diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
index 5e05ec3df37011fbeb2859310e638c1be8513385..e7e51d171723c0c721c7a909cd69bc598c44fdcc 100644 (file)
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -267,10 +267,6 @@ ExecHashTableCreate(Hash *node, List *hashOperators, bool keepNulls)
                            OidIsValid(node->skewTable),
                            &nbuckets, &nbatch, &num_skew_mcvs);
 
-#ifdef HJDEBUG
-   printf("nbatch = %d, nbuckets = %d\n", nbatch, nbuckets);
-#endif
-
    /* nbuckets must be a power of 2 */
    log2_nbuckets = my_log2(nbuckets);
    Assert(nbuckets == (1 << log2_nbuckets));
@@ -311,6 +307,11 @@ ExecHashTableCreate(Hash *node, List *hashOperators, bool keepNulls)
        hashtable->spaceAllowed * SKEW_WORK_MEM_PERCENT / 100;
    hashtable->chunks = NULL;
 
+#ifdef HJDEBUG
+   printf("Hashjoin %p: initial nbatch = %d, nbuckets = %d\n",
+          hashtable, nbatch, nbuckets);
+#endif
+
    /*
     * Get info about the hash functions to be used for each hash key. Also
     * remember whether the join operators are strict.
@@ -615,8 +616,8 @@ ExecHashIncreaseNumBatches(HashJoinTable hashtable)
    Assert(nbatch > 1);
 
 #ifdef HJDEBUG
-   printf("Increasing nbatch to %d because space = %lu\n",
-          nbatch, (unsigned long) hashtable->spaceUsed);
+   printf("Hashjoin %p: increasing nbatch to %d because space = %zu\n",
+          hashtable, nbatch, hashtable->spaceUsed);
 #endif
 
    oldcxt = MemoryContextSwitchTo(hashtable->hashCxt);
@@ -731,8 +732,8 @@ ExecHashIncreaseNumBatches(HashJoinTable hashtable)
    }
 
 #ifdef HJDEBUG
-   printf("Freed %ld of %ld tuples, space now %lu\n",
-          nfreed, ninmemory, (unsigned long) hashtable->spaceUsed);
+   printf("Hashjoin %p: freed %ld of %ld tuples, space now %zu\n",
+          hashtable, nfreed, ninmemory, hashtable->spaceUsed);
 #endif
 
    /*
@@ -747,7 +748,8 @@ ExecHashIncreaseNumBatches(HashJoinTable hashtable)
    {
        hashtable->growEnabled = false;
 #ifdef HJDEBUG
-       printf("Disabling further increase of nbatch\n");
+       printf("Hashjoin %p: disabling further increase of nbatch\n",
+              hashtable);
 #endif
    }
 }
@@ -767,8 +769,8 @@ ExecHashIncreaseNumBuckets(HashJoinTable hashtable)
        return;
 
 #ifdef HJDEBUG
-   printf("Increasing nbuckets %d => %d\n",
-          hashtable->nbuckets, hashtable->nbuckets_optimal);
+   printf("Hashjoin %p: increasing nbuckets %d => %d\n",
+          hashtable, hashtable->nbuckets, hashtable->nbuckets_optimal);
 #endif
 
    hashtable->nbuckets = hashtable->nbuckets_optimal;
@@ -814,11 +816,6 @@ ExecHashIncreaseNumBuckets(HashJoinTable hashtable)
                            HJTUPLE_MINTUPLE(hashTuple)->t_len);
        }
    }
-
-#ifdef HJDEBUG
-   printf("Nbuckets increased to %d, average items per bucket %.1f\n",
-          hashtable->nbuckets, batchTuples / hashtable->nbuckets);
-#endif
 }