use adventureworks2012;
go
drop table sales2;
create table sales2 (
[id] int not null identity (1,1),
[date] date not null,
itemid smallint not null,
price money not null,
quantity numeric(18,4) not null)
;
go
create unique clustered index cdx_sales2_date_id on sales2 ([date], [id]);
go
set nocount on;
go
–insert sales2
declare @i int = 0;
declare @date datetime2;
begin transaction;
while @i 0
order by t.name, au.type
go
set statistics io on;
go
select [date], sum(price*quantity) from sales2 with (index(cs_sales2_price)) where date = ’20110713′ group by [date]
go
set statistics io off;
go

ok so far… then I checked allocated Pages:

select t.name, au.* from sys.system_internals_allocation_units au
join sys.system_internals_partitions p
join sys.tables t on p.object_id = t.object_id
on p.partition_id = au.container_id
where (
p.object_id = object_id(‘sales2′))
and total_pages >0
order by t.name, au.type
go

result: 1002 pages for the columnstore index

Then I executed

set statistics io on;
go
select [date], sum(price*quantity) from sales2 with (index(cs_sales2_price)) where date = ’20110713′ group by [date]
go
set statistics io off;
go

Result:
Table ‘sales2′. Scan count 1, logical reads 1355, physical reads 0, read-ahead reads 4706, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

WHAT?? 1355 logical reads? Why are there 353 reads more than allocated pages?

CREATE INDEX statement failed because a columnstore index cannot be created in this edition of SQL server.

Pl. help me.

Absolute gem of an article and a very significant feature for SQL Server in the Big Data world! Thanks

Not able to truncate data from a table with column store index even after disabling the index. We can delete the data but not truncate. If you ever aware of this, can you please suggest any work around on it other than dropping and recreating column-store index.

Set statistics IO On
Select PortfolioID,StrategyID,SignalID,SecID,NoTrds=count(*),SUM(PL) from
(
SELECT [TradeID]
,[PortfolioID]
,[StrategyID]
,[SignalID]
,[SecID]
,PL=case when LongStatus=1 then (EntryPrice-ExitPrice)* EntryQty else (EntryPrice-ExitPrice)* EntryQty*-1 END

FROM [PST_BANK]
) As A group by PortfolioID,StrategyID,SignalID,SecID

It gives the following message

Table ‘PST_BANK’. Scan count 18, logical reads 22580, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table ‘Worktable’. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

Now i create the columnstore index as follows:

create nonclustered columnstore index[Neeaj_Index]
ON [pst_Bank] (portfolioID,strategyId,SignalID,SecID)

Set statistics IO On
Select PortfolioID,StrategyID,SignalID,SecID,NoTrds=count(*),SUM(PL) from
(
SELECT [TradeID]
,[PortfolioID]
,[StrategyID]
,[SignalID]
,[SecID]
,PL=case when LongStatus=1 then (EntryPrice-ExitPrice)* EntryQty else (EntryPrice-ExitPrice)* EntryQty*-1 END

FROM [PST_BANK] with (INDEX (Neeaj_Index))
) As A group by PortfolioID,StrategyID,SignalID,SecID

it gives following message

Table ‘Worktable’. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table ‘PST_BANK’. Scan count 6, logical reads 4461739, physical reads 0, read-ahead reads 1515, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table ‘Worktable’. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

The number of logical read increases….why??