diff --git a/block_storage.py b/block_storage.py
index 43cd0b8..ddb39b0 100644
--- a/block_storage.py
+++ b/block_storage.py
@@ -5,6 +5,7 @@
 import google.protobuf.json_format
 import binascii
 import hashlib
+import multiprocessing
 
 from schema_version import *
 
@@ -37,6 +38,37 @@ def iterate(self):
             yield block
             height += 1
 
+    def iterate_with_callable(self, func):
+        'WARNING func must be thread safe!'
+        current_height = multiprocessing.Value('i')
+        current_height.value = 0
+
+        def load_and_feed_next_block():
+            def load_block(height=current_height):
+                with height.get_lock():
+                    height_local = height.value
+                    height.value += 1
+                    return self.load_at_height(height_local)
+
+            for block in iter(load_block, None):
+                func(block)
+
+        pool = list()
+
+        for _ in range(multiprocessing.cpu_count()):
+            process = multiprocessing.Process(target=load_and_feed_next_block)
+            process.start()
+            pool.append(process)
+
+        for process in pool:
+            process.join()
+
+        for process in pool:
+            if process.exitcode != 0:
+                raise Exception(
+                    f'BlockStorageFiles: child process {process.name} exited with code {process.exitcode}'
+                )
+
     def _get_block_file_path_at_height(self, height: int) -> str:
         return os.path.join(self._path, '{0:0>16}'.format(height))
 
diff --git a/migration_data/release_1_2_0.py b/migration_data/release_1_2_0.py
index 749488a..edf75cb 100644
--- a/migration_data/release_1_2_0.py
+++ b/migration_data/release_1_2_0.py
@@ -1,5 +1,6 @@
 import itertools
 import json
+import multiprocessing
 
 
 def migrate_1_1_3_to_1_2_0(cursor, block_storage):
@@ -34,24 +35,33 @@ def migrate_1_1_3_to_1_2_0(cursor, block_storage):
     cursor.execute(
         'create table blockstorage_data (h bigint, i bigint, t bigint)')
 
-    def get_blocks_data(blocks):
-        for block in blocks:
-            height = block.block_v1.payload.height
-            for index, tx in enumerate(block.block_v1.payload.transactions):
-                yield {
-                    'h': height,
-                    'i': index,
-                    't': tx.payload.reduced_payload.created_time
-                }
-
-    BULK_SZ = 1000
-    it = iter(get_blocks_data(block_storage.iterate()))
-    while True:
-        chunk = tuple(itertools.islice(it, BULK_SZ))
-        if len(chunk) == 0: break
-        cursor.execute(
-            'insert into blockstorage_data (select * from json_populate_recordset(null::blockstorage_data, %s))',
-            (json.dumps(chunk), ))
+    multiprocessing_manager = multiprocessing.Manager()
+    block_data_to_submit = multiprocessing_manager.Queue()
+
+    def get_block_data(block):
+        height = block.block_v1.payload.height
+        for index, tx in enumerate(block.block_v1.payload.transactions):
+            block_data_to_submit.put(
+                (height, index, tx.payload.reduced_payload.created_time))
+
+    def submit_block_data(block_data_to_submit):
+        BULK_SZ = 1000
+        data = iter(block_data_to_submit.get, 'stop')
+        while True:
+            chunk = tuple(itertools.islice(data, BULK_SZ))
+            if len(chunk) == 0: break
+            cursor.execute(
+                'insert into blockstorage_data (h, i, t) values {}'.format(
+                    ', '.join(map(str, chunk))))
+
+    block_data_submitter = multiprocessing.Process(
+        target=submit_block_data, args=(block_data_to_submit, ))
+    block_data_submitter.start()
+
+    block_storage.iterate_with_callable(get_block_data)
+
+    block_data_to_submit.put('stop')
+    block_data_submitter.join()
 
     # now merge the tables and block storage data
     cursor.execute('''
@@ -63,16 +73,6 @@ def get_blocks_data(blocks):
             height bigint,
             index bigint
         );
-        CREATE INDEX IF NOT EXISTS tx_positions_hash_index
-            ON tx_positions
-            USING hash
-            (hash);
-        CREATE INDEX IF NOT EXISTS tx_positions_creator_id_asset_index
-            ON tx_positions
-            (creator_id, asset_id);
-        CREATE INDEX IF NOT EXISTS tx_positions_ts_height_index_index
-            ON tx_positions
-            (ts);
 
         -- aux constraint to avoid duplicate rows
         alter table tx_positions
@@ -126,6 +126,18 @@ def get_blocks_data(blocks):
         -- drop aux stuff
         drop table blockstorage_data;
         alter table tx_positions drop constraint aux_tx_positions_unique_constraint cascade;
+
+        -- create indices
+        CREATE INDEX IF NOT EXISTS tx_positions_hash_index
+            ON tx_positions
+            USING hash
+            (hash);
+        CREATE INDEX IF NOT EXISTS tx_positions_creator_id_asset_index
+            ON tx_positions
+            (creator_id, asset_id);
+        CREATE INDEX IF NOT EXISTS tx_positions_ts_height_index_index
+            ON tx_positions
+            (ts);
             ''')
 
     # burrow stuff