diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 0d9663c..db3a953 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -1900,18 +1900,20 @@ show_hash_info(HashState *hashstate, ExplainState *es)
 		if (es->format != EXPLAIN_FORMAT_TEXT)
 		{
 			ExplainPropertyLong("Hash Buckets", hashtable->nbuckets, es);
+			ExplainPropertyLong("Original Hash Buckets",
+								hashtable->nbuckets_original, es);
 			ExplainPropertyLong("Hash Batches", hashtable->nbatch, es);
 			ExplainPropertyLong("Original Hash Batches",
 								hashtable->nbatch_original, es);
 			ExplainPropertyLong("Peak Memory Usage", spacePeakKb, es);
 		}
-		else if (hashtable->nbatch_original != hashtable->nbatch)
+		else if ((hashtable->nbatch_original != hashtable->nbatch) || (hashtable->nbuckets_original != hashtable->nbuckets))
 		{
 			appendStringInfoSpaces(es->str, es->indent * 2);
 			appendStringInfo(es->str,
-			"Buckets: %d  Batches: %d (originally %d)  Memory Usage: %ldkB\n",
-							 hashtable->nbuckets, hashtable->nbatch,
-							 hashtable->nbatch_original, spacePeakKb);
+			"Buckets: %d (originally %d)  Batches: %d (originally %d)  Memory Usage: %ldkB\n",
+							 hashtable->nbuckets, hashtable->nbuckets_original,
+							 hashtable->nbatch, hashtable->nbatch_original, spacePeakKb);
 		}
 		else
 		{
diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
index 589b2f1..879b336 100644
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -39,6 +39,7 @@

 static void ExecHashIncreaseNumBatches(HashJoinTable hashtable);
+static void ExecHashIncreaseNumBuckets(HashJoinTable hashtable);
 static void ExecHashBuildSkewHash(HashJoinTable hashtable, Hash *node,
 					  int mcvsToUse);
 static void ExecHashSkewTableInsert(HashJoinTable hashtable,
@@ -271,6 +272,7 @@ ExecHashTableCreate(Hash *node, List *hashOperators, bool keepNulls)
 	 */
 	hashtable = (HashJoinTable) palloc(sizeof(HashJoinTableData));
 	hashtable->nbuckets = nbuckets;
+	hashtable->nbuckets_original = nbuckets;
 	hashtable->log2_nbuckets = log2_nbuckets;
 	hashtable->buckets = NULL;
 	hashtable->keepNulls = keepNulls;
@@ -386,6 +388,22 @@ ExecHashTableCreate(Hash *node, List *hashOperators, bool keepNulls)
 /* Target bucket loading (tuples per bucket) */
 #define NTUP_PER_BUCKET			10

+/* Multiple of NTUP_PER_BUCKET triggering the increase of nbuckets.
+ * 
+ * Once we reach the threshold we double the number of buckets, and we
+ * want to get 1.0 on average (to get NTUP_PER_BUCKET on average). That
+ * means these two equations should hold
+ * 
+ *   b = 2a         (growth)
+ *   (a + b)/2 = 1  (oscillate around NTUP_PER_BUCKET)
+ * 
+ * which means b=1.3333 (a = b/2). If we wanted higher threshold, we
+ * could grow the nbuckets to (4*nbuckets), thus using (b=4a) for
+ * growth, leading to (b=1.6). Or (b=8a) giving 1.7777 etc.
+ * 
+ * Let's start with doubling the bucket count, i.e. 1.333. */
+#define NTUP_GROW_THRESHOLD     1.333
+
 void
 ExecChooseHashTableSize(double ntuples, int tupwidth, bool useskew,
 						int *numbuckets,
@@ -682,6 +700,92 @@ ExecHashIncreaseNumBatches(HashJoinTable hashtable)
 }

 /*
+ * ExecHashIncreaseNumBuckets
+ *		increase the original number of buckets in order to reduce
+ *		number of tuples per bucket
+ */
+static void
+ExecHashIncreaseNumBuckets(HashJoinTable hashtable)
+{
+	int			i;
+	int         ntuples = 0;
+	int			oldnbuckets = hashtable->nbuckets;
+	HashJoinTuple  *oldbuckets = hashtable->buckets;
+	MemoryContext   oldcxt;
+
+	/* XXX Not sure if we should update the info about used space here.
+	 * The code seems to ignore the space used for 'buckets' and we're not
+	 * allocating more space for tuples (just shuffling them to the new
+	 * buckets). And the amount of memory used for buckets is quite small
+	 * (just an array of pointers, thus ~8kB per 1k buckets on 64-bit). */
+
+	/* XXX Should we disable growth if (nbuckets * NTUP_PER_BUCKET)
+	 * reaches work_mem (or something like that)? We shouldn't really
+	 * get into such position (should be handled by increasing the
+	 * number of batches, which is called right before this). */
+
+	/* XXX Maybe adding info into hashjoin explain output (e.g. initial
+	 * nbuckets, time spent growing the table) would be appropriate. */
+
+	/* update the hashtable info, so that we can compute buckets etc. */
+	hashtable->log2_nbuckets += 1;
+	hashtable->nbuckets *= 2;
+
+	Assert(hashtable->nbuckets > 1);
+	Assert(hashtable->nbuckets == (1 << hashtable->log2_nbuckets));
+
+#ifdef HJDEBUG
+	printf("Increasing nbuckets to %d\n", hashtable->nbuckets);
+#endif
+
+	/* TODO Maybe it'd be better to resize the buckets in place (should be possible,
+	 * but when I tried it I always ended up with a strange infinite loop). */
+
+	/* allocate a new bucket list (use the batch context as before) */
+	oldcxt = MemoryContextSwitchTo(hashtable->batchCxt);
+
+	hashtable->buckets = (HashJoinTuple *) palloc0(hashtable->nbuckets * sizeof(HashJoinTuple));
+
+	MemoryContextSwitchTo(oldcxt);
+
+	/* walk through the old buckets, move the buckets into the new table */
+	for (i = 0; i < oldnbuckets; i++)
+	{
+
+		HashJoinTuple tuple = oldbuckets[i];
+
+		while (tuple != NULL)
+		{
+			/* save link in case we delete */
+			HashJoinTuple nexttuple = tuple->next;
+			int			bucketno;
+			int			batchno;
+
+			ExecHashGetBucketAndBatch(hashtable, tuple->hashvalue,
+									  &bucketno, &batchno);
+
+			/* move it to the correct bucket */
+			tuple->next = hashtable->buckets[bucketno];
+			hashtable->buckets[bucketno] = tuple;
+
+			/* process the next tuple */
+			tuple = nexttuple;
+
+			ntuples++;
+		}
+	}
+
+	pfree(oldbuckets);
+
+#ifdef HJDEBUG
+	printf("Nbuckets increased to %d, average items per bucket %.1f\n",
+		   hashtable->nbuckets, (float)ntuples / hashtable->nbuckets);
+#endif
+
+}
+
+
+/*
  * ExecHashTableInsert
  *		insert a tuple into the hash table depending on the hash value
  *		it may just go to a temp file for later batches
@@ -740,6 +844,22 @@ ExecHashTableInsert(HashJoinTable hashtable,
 			hashtable->spacePeak = hashtable->spaceUsed;
 		if (hashtable->spaceUsed > hashtable->spaceAllowed)
 			ExecHashIncreaseNumBatches(hashtable);
+
+		/* check average number of tuples per bucket, increase (2*nbuckets) if needed */
+		/* FIXME This attempts to compute number of tuples in the hashtable using hashTupleSize,
+		 * 		 i.e. the size of the current tuple, which is not really accurate. Need to track
+		 * 		 the count properly.
+		 */
+		if (hashtable->spaceUsed / hashTupleSize / hashtable->nbuckets > NTUP_GROW_THRESHOLD * NTUP_PER_BUCKET) {
+
+#ifdef HJDEBUG
+			printf("Increasing nbucket to %d because average per bucket = %d\n",
+				   nbuckets,  hashtable->spaceUsed / hashTupleSize / hashtable->nbuckets);
+#endif
+
+			ExecHashIncreaseNumBuckets(hashtable);
+		}
+
 	}
 	else
 	{
diff --git a/src/include/executor/hashjoin.h b/src/include/executor/hashjoin.h
index 3beae40..03e91a6 100644
--- a/src/include/executor/hashjoin.h
+++ b/src/include/executor/hashjoin.h
@@ -106,6 +106,7 @@ typedef struct HashSkewBucket
 typedef struct HashJoinTableData
 {
 	int			nbuckets;		/* # buckets in the in-memory hash table */
+	int			nbuckets_original;	/* # buckets when starting the first hash */
 	int			log2_nbuckets;	/* its log2 (nbuckets must be a power of 2) */

 	/* buckets[i] is head of list of tuples in i'th in-memory bucket */