diff --git a/src/spark/main.py b/src/spark/main.py
index 4c20f72..bfa179d 100644
--- a/src/spark/main.py
+++ b/src/spark/main.py
@@ -1,9 +1,4 @@
-from gc import collect
 import json
-from select import select
-
-from sqlite3 import Row
-from typing import Iterable, List
 
 from pyspark.sql import SparkSession, DataFrame, Row
 from pyspark.sql import functions as F
@@ -56,46 +51,18 @@ class Master:
             .rdd \
             .flatMap(lambda row: list(map(lambda elem: (elem,), row[column]))) \
             .toDF([column])
-
-    def array_col_to_elements(self, df: DataFrame, column: str, distinct:bool = False) -> DataFrame:
-        exploded = master.explode_array_col(
-            df,
-            column
-        )
-
-        #this is likely redundant
-        collected = master.collect_col_to_array(
-            exploded, 
-            column, 
-            distinct
-        )
-
-        return self.explode_array_col(
-            collected,
-            column
-        )
-
 # end class Master
 
 
 master = Master(config)
+master.spark.catalog.clearCache()
+master.spark.sparkContext.setCheckpointDir('./checkpoints')
 tx_df = master.get_tx_dataframe()
 
-
 #Turn transactions into a list of ('id', [addr, addr, ...])
 tx_grouped = tx_df \
     .groupBy('tx_id') \
-    .agg(F.collect_set('address').alias('addresses')) \
-    .rdd \
-    .zipWithIndex() \
-    .toDF(['tx', 'index']) \
-    .select(
-        F.col('tx.tx_id').alias('tx_id'),
-        F.col('tx.addresses').alias('addresses'),
-        'index'
-    ) \
-    .cache()
-
+    .agg(F.collect_set('address').alias('addresses'))
 
 # TODO: Load clusters from DB, check if any exist, if no make initial cluster, else proceed with loaded data
 
@@ -103,29 +70,39 @@ tx_grouped = tx_df \
 
 # take the first tx
 tx_zero = tx_grouped \
-    .select(tx_grouped.tx_id, tx_grouped.addresses) \
-    .where(tx_grouped.index == 0)
+    .select('*') \
+    .where('tx_id = 3') \
+    .limit(1)
 
 # find txs with overlapping addresses
 overlapping_txs = tx_grouped \
-    .where((tx_grouped.index != 0)) \
-    .join(tx_zero.withColumnRenamed('addresses', 'tx_addresses')) \
+    .join(
+        tx_zero \
+            .withColumnRenamed('addresses', 'tx_addresses') \
+            .withColumnRenamed('tx_id', 'overlap_id')
+    ) \
     .select(
-        tx_grouped.index,
+        tx_grouped.tx_id,
         tx_grouped.addresses,
         F.arrays_overlap(tx_grouped.addresses, 'tx_addresses').alias('overlap')
     ) \
     .where(F.col('overlap') == True) \
+    .drop('overlap')
 
 # overlapped txs must not be considered anymore, so remove them candidate dataframe
 tx_grouped = tx_grouped \
-    .join(overlapping_txs, 'index', 'leftanti') \
-    .filter(tx_grouped.index != 0)
+    .join(
+        overlapping_txs.drop('addresses'), 
+        'tx_id', 
+        'leftanti'
+    )
 
 # get the distinct addresses of all overlaps in a single array
 distinct_addresses = master.reduce_concat_array_column(
     master.union_single_col(
-        overlapping_txs, tx_zero, column='addresses'
+        overlapping_txs, 
+        tx_zero, 
+        column='addresses'
     ), 
     column='addresses',
     distinct=True,
@@ -144,7 +121,7 @@ clusters_grouped = cluster \
     .groupBy('id') \
     .agg(F.collect_list('address').alias('addresses'))
 
-def take_tx_and_cluster(txs: DataFrame, clusters: DataFrame):
+def take_tx_and_cluster(txs: DataFrame, clusters: DataFrame, n=0):
     if (txs.count() == 0):  # done!
         return clusters
 
@@ -158,33 +135,43 @@ def take_tx_and_cluster(txs: DataFrame, clusters: DataFrame):
         .select(
             clusters.id,
             clusters.addresses,
+            'tx_addresses',
             F.arrays_overlap(clusters.addresses,'tx_addresses').alias('overlap')
         ) \
         .where(F.col('overlap') == True)
 
+    clusters_union_tx = master.union_single_col(tx, overlapping_clusters, 'addresses')
+
     #collect all addresses into single array field
-    new_cluster_arr = master.reduce_concat_array_column(
-        master.union_single_col(tx, overlapping_clusters, 'addresses'),
+    new_cluster_arrays = master.reduce_concat_array_column(
+        clusters_union_tx,
         column='addresses',
         distinct=True
     )
 
     #declare cluster representative
-    new_cluster = new_cluster_arr \
+    new_cluster = new_cluster_arrays \
         .rdd \
         .flatMap(lambda row: list(map(lambda addr: (addr, row['addresses'][0]), row['addresses']))) \
         .toDF(['address', 'id']) \
         .groupBy('id') \
         .agg(F.collect_list('address').alias('addresses'))
 
+    txs = txs.join(tx, 'tx_id', 'leftanti')
+    clusters = clusters.join(overlapping_clusters, 'id', 'leftanti').union(new_cluster)
+
+    #the RDD legacy (internal history tracker) gets too big as iterations continue, use checkpoint to prune it regularly
+    if(n % 3 == 0):
+        txs = txs.checkpoint()
+        clusters = clusters.checkpoint()
+
     #start new round with txs minus the one just used, and updated clusters
-    return take_tx_and_cluster(
-        txs.join(tx, 'index', 'leftanti'), 
-        clusters.join(overlapping_clusters, 'id', 'leftanti').union(new_cluster)
-    )
+    return take_tx_and_cluster(txs,clusters,n+1)
 
 
-take_tx_and_cluster(tx_grouped, clusters_grouped).show()
+result = take_tx_and_cluster(tx_grouped, clusters_grouped).collect()
+for row in result:
+    print(sorted(row['addresses']))
 
 end = time.time()
 print("ELAPSED TIME:", end-start)