I am new to MapD so bare with my ignorance about few topics.
I have setup MapD v4.0 on my laptop (CPU only, Ubuntu 16.06), I was trying to validate TPC-DS benchmark locally before I try it on a GPU node, so I generated a small test data set of size = 1 GB and loaded in MapD tables.
Now I am trying to run the queries generated in ANSI dialect format (pls correct me if any other dialect needs to be used). I am getting serialization error for couple if queries and want to understand what it means and what can be done to fix the queries.
Here is one example query -
select count(distinct cs_order_number) as order_count,sum(cs_ext_ship_cost) as total_shipping_cost,sum(cs_net_profit) as total_net_profit from catalog_sales cs1,date_dim,customer_address,call_center where d_date between ‘1999-5-01’ and (cast(‘1999-5-01’ as date) + INTERVAL ‘60’ day) and cs1.cs_ship_date_sk=d_date_sk and cs1.cs_ship_addr_sk=ca_address_sk and ca_state=‘ID’ and cs1.cs_call_center_sk=cc_call_center_sk and cc_county in (‘Williamson County’,‘Williamson County’,‘Williamson County’,‘Williamson County’, ‘Williamson County’ ) and exists (select * from catalog_sales cs2 where cs1.cs_order_number=cs2.cs_order_number and cs1.cs_warehouse_sk <> cs2.cs_warehouse_sk) and not exists(select * from catalog_returns cr1 where cs1.cs_order_number=cr1.cr_order_number) order by count(distinct cs_order_number);
Error - Exception: Exception occurred: type not serializable: [$cor0] (type com.google.common.collect.SingletonImmutableSet)
I could not get much information from the log, but I ran queries in sub-parts and it looks like exists function is not supported therefore the query fails.
Q 1 - Is there any listing available on set of supported/unsupported functions?
Q 2 - Does serialization error always indicate an unsupported function/operation? How should one debug and fix such queries?
Let me know if any further information is needed from my end.