Monday, 2 November 2015
Tuesday, 4 November 2014
Tuesday, 14 October 2014
Firstly get with the program, http://windows.microsoft.com/en-gb/windows/preview
Download the ISO, create a new virtual machine and bish bash bosh - minutes later, Windows X
(using a VMWare Fusion on my macbook pro)
It feels like Windows 7.5 (!) ;-)
File History - interesting - is this the start of TimeMachine for windows? (Perhaps not) - I will play when I attach a USB drive.
Well thats it for now, it looks good, its quick, I might just switch over as my main OS. ;-)
Wednesday, 30 July 2014
2) Calendar with community events in it
4) To produce server build documentation
5) A quick way of seeing all the extended properties on a table and all its columns. And editing them!
6) Some way of indicating the IDENTITY column if there is one?
7) Something that shows the partitioning wouldn't go amiss either and the age of the stats
8) Size of the table in Kb/Mb? Same with the indexes?
9) Is it possible to see number of table reads/scans for a particular table?
10) A feature that says "Please remove this software from your computer as you clearly have not idea what you are doing!"? I would prefer something that gives electric shocks as well but I think that Amnesty International and the unions may have object to that!!
Sunday, 27 July 2014
Friday, 23 May 2014
Thursday, 11 July 2013
When its a rowstore index.
When its not been rebuilt.
The answer is on MSDN – “The updateable columnstore first inserts new data into an OPEN rowgroup, which is in rowstore format” –> Yes, rowstore, not column store.
MSDN says re-organising the index will put it in columnstore format, but in CTP1 this doesn’t work. You need to rebuild the index, not a problem because we are using developer edition (or enterprise edition).
I’ve blogged here what happens when you insert into a column store index here
Tuesday, 9 July 2013
In my series on the Column Store Index, I thought I would blog on what happens when you insert/ delete into a column store index.
1) Lets insert some rows into a table with a column store index.
2) Rebuild the Index. The state of index changes to Compressed from Open and size_in_bytes is populated.
3) Insert some more rows. We now have two rows, one ‘OPEN’ and second ‘COMPRESSED’
4) Delete some rows. The deleted rows appear to have come from the ‘COMPRESSED’ row.
5) Rebuild the index again.
6) When I updated 1 row in the COMPRESSED table, the engine deleted the row and added a new row in the OPEN / delta table.
The page on MSDN about the sys.column_store_row_groups system table http://msdn.microsoft.com/en-us/library/dn223749(v=sql.120).aspx , explains why the 2nd table / delta table or delta row set is used , how and when data is moved from open of the threee states; ‘OPEN’,’COMPRESSED' and ‘CLOSED’ – I’ve not seen ‘CLOSED’ yet.
Last week I blogged on the Clustered Column store index, I’ve been playing with it – its very early days, as its a feature of SQL2014 CTP1.
Just to recap. I noticed that something wasn’t working as I expected.
The number of rows returned from the report ‘Disk usage by table’ is incorrect, shown by the top results set, the correct number is shown from select count (*) query and the select from sys.partitions.
Also notice on sys.partitions, the compression description.
So how do I get the standard report to show the right data?
Well, restarting the instance doesn’t help.
But what about rebuilding / re-organising the index? Re-organising the index does nothing, but rebuilding the index works!
All the counts are returning the expected number of rows, now everything is alright with the world.
Wednesday, 26 June 2013
After more digging, I’ve found a link on msdn to information about the new system table sys.column_store_row_groups. http://msdn.microsoft.com/en-us/library/dn223749(v=sql.120).aspx
This bit “The hobt_id for delta row groups, or NULL if the row group type is not delta. A delta row group is a read/write row group that is accepting new records. A delta row group has the OPEN status. A delta row group is still in rowstore format and has not been compressed to columnstore format.”
So this sounds like there are still two tables [or row groups], the delta row group which you can read and write into and a 2nd row group which is compressed.
This is the work-around people have been using with the non-updateable column store indexes to make to work like they are updateable, but its happening behind the scenes.
Very very nice.
I’ve previously blogged on some interesting things about the clustered column store index or CCSI for short.
I’ve found my CCSI in an internal table. sys.Column_store_row_groups
Noticed the size_in_byte…NULL
Just for fun, I tried to create a 2nd column store index on the same table. (Non-clustered of course)
So we can’t add a non-clustered column store index (NCCSI) to a table that already has a CCSI.
But can we add two NCCSI to a table? The answer is no, but the UI doesn’t let you get that far. Its non-selectable.. interesting..
And more digging….
I downloaded SQL Server 2014 CPT1 last night and I’ve started playing with it.
I’m really interested in the updateable clustered column store index, so I thought I would see if it works in the CTP1 (not all features are released in the CTPs)
I created two identical tables, added a Clustered Column store index to one of them, and inserted 15000 rows into both of them.
Guess what, it only bloody worked! Excellent! Happy bunny.
So the next step, how does it work? While looking at the IO for the insert, I stumbled on this..
TestTB_1 has 15,000 rows and TestTB_2 has 0 rows… Wait a second, that’s not right.
No – There are 15,000 records in both tables.
Wow – check out the logical reads,physical reads…etc…etc..
All coming back as 0 – I guess the column store engine isnt reporting back in the same way the normal engine is.
This will get fixed at some point, no doubt, but the fact that the column store index was updated is so cool…
I’m going to do some more digging now…