batch get_blocks_at (#6475)

* batch get blocks at

* test

* comment

chia/consensus/blockchain.py

@@ -685,14 +685,24 @@ class Blockchain(BlockchainInterface):
             return None
         return header_dict[header_hash]
 
-    async def get_block_records_at(self, heights: List[uint32]) -> List[BlockRecord]:
+    async def get_block_records_at(self, heights: List[uint32], batch_size=900) -> List[BlockRecord]:
         """
         gets block records by height (only blocks that are part of the chain)
         """
+        records: List[BlockRecord] = []
         hashes = []
+        assert batch_size < 999  # sqlite in python 3.7 has a limit on 999 variables in queries
         for height in heights:
             hashes.append(self.height_to_hash(height))
-        return await self.block_store.get_block_records_by_hash(hashes)
+            if len(hashes) > batch_size:
+                res = await self.block_store.get_block_records_by_hash(hashes)
+                records.extend(res)
+                hashes = []
+
+        if len(hashes) > 0:
+            res = await self.block_store.get_block_records_by_hash(hashes)
+            records.extend(res)
+        return records
 
     async def get_block_record_from_db(self, header_hash: bytes32) -> Optional[BlockRecord]:
         if header_hash in self.__block_records:

tests/blockchain/test_blockchain.py

@@ -2589,3 +2589,17 @@ class TestReorgs:
             != blocks_without_filter[header_hash].transactions_filter
         )
         assert blocks_with_filter[header_hash].header_hash == blocks_without_filter[header_hash].header_hash
+
+    @pytest.mark.asyncio
+    async def test_get_blocks_at(self, empty_blockchain, default_1000_blocks):
+        b = empty_blockchain
+        heights = []
+        for block in default_1000_blocks[:200]:
+            heights.append(block.height)
+            result, error_code, _ = await b.receive_block(block)
+            assert error_code is None and result == ReceiveBlockResult.NEW_PEAK
+
+        blocks = await b.get_block_records_at(heights, batch_size=2)
+        assert blocks
+        assert len(blocks) == 200
+        assert blocks[-1].height == 199