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1
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0answers
14 views

Column Store Indices versus Dimensional Tables

I have a Data Warehouse and want to think ahead one year when I may get a database update allowing me to use column store indices. My dimensional tables are mostly junk dimensions containing columns ...
3
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1answer
38 views

Why does the Tuple Mover in C-Store consider only rows older than LWM?

In the Tuple Mover section of the C-Store paper by Michael Stonebraker (link: http://db.csail.mit.edu/projects/cstore/vldb.pdf) the following is described: MOP (merge out process) will find all ...
2
votes
1answer
34 views

Building a ColumnStore index hogs system resources

I am experimenting with the columnstore and I am finding that while it is building the process hogs all the system resources. I have a table with 2.3 billion rows and while I build the columnstore on ...
3
votes
1answer
59 views

Column Store Index over an clustered index (created when primary key is declared) - SQL Server

When a clustered index is created, the table itself becomes the index structure sorted by the index key. Imagine now that we have 5 columns in a table XPTO (a,b,c,d,e) and "a" is the primary key and ...
0
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2answers
59 views

How can we get the table and the column name of known data value?

I have a value (like 'IT department'), based on this I want to get the table and column name in which this value exists/present.
1
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1answer
64 views

Column store index on a large fact table

I have seen column store index and also tested it. I have no doubt admiring that it is lightning fast. But every tutorial and blogs I have considered, says about its limitation "table will become read ...
0
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0answers
31 views

Columnstore Index Scan Cardinality Estimates

In SQL Server 2012, I am seeing large cardinality estimate discrepancies for a columnstore index scan. It looks like statistics have been generated for the index, but I don't see any details in DBCC ...
13
votes
1answer
324 views

What exactly can SQL Server 2014 execute in batch mode?

When a columnstore index is being used in a query SQL Server is able to use batch mode. Documentation is thin on what can run in batch mode and what can't. Please look at the following (motivating) ...
0
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1answer
29 views

NC Columnstore and delete on batch

hope you can give me some pointers on this behavior I have a NC Columnstore and in the same batch I want to drop this column store and "delete" some information. But I get this error: DELETE ...
0
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0answers
35 views

Oracle In-Memory POPULATE_STATUS does not change to completed

I'm experimenting with the Oracle In-memory options for BI purposes, when I'm trying to populate one table to in-memory in the v$im_segments the POPULATE_STATUS does not change to completed, for other ...
0
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0answers
32 views

Greenplum database storage model for time series data

I have to deploy a greenplum database for analysis of time series data. I will have around 50 different time series (s1,s2,s3,...s50) and each series will have multiple pairs (time is 1 hour average ...
0
votes
1answer
135 views

How to create column group in WiredTiger engine in mongodb 2.8?

MongoDB 2.8 supports WiredTiger strorage engine, and WiredTiger supports column grouping. How we can create a collection in mongodb 2.8 with grouped columns?
5
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3answers
267 views

Has the guidance on the setting for 'cost threshold for parallelism' changed with the advent of columnstore indexes?

First off, what I'm not asking. I'm not asking what my setting should be. Many are recommending upping the value past the default, and I certainly understand why that's the case for B-Tree based ...
13
votes
2answers
979 views

Clustered columnstore indexes and foreign keys

I am performance tuning a data warehouse using indexes. I am fairly new to SQL Server 2014.Microsoft describes the following: "We view the clustered columnstore index as the standard for storing ...
3
votes
1answer
118 views

sp_estimate_data_compression_savings for column store compressions

Is there a way to get compressions saving for column store and column store column store archival compression? In order to check these compressions saving I have to drop all clustered and non ...
0
votes
1answer
135 views

Msg 823, Level 24, State 2 for Clustered Column Store Index in SQL Server 2014

CREATE CLUSTERED COLUMNSTORE INDEX CCI_TempTable1 ON dbo.TempTable1 ON[PRIMARY] After firing this query I found the error. Msg 823, Level 24, State 2, Line 20 The operating system returned error ...
1
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0answers
33 views

Does the order of columns in a non-clustered ColumnStore index matter? [duplicate]

I'm reading about creating a non-clustered ColumnStore index. I noticed that when I modify an already created non-clustered ColumnStore in SQL Server Management Studio I have an option to change the ...
1
vote
2answers
3k views

Create failed for Index 'ClusteredColumnStoreIndex'. Timeout expired

I am creating Clustered Column Store Index in SQL Server 2014. I am getting error as "Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not ...
2
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2answers
212 views

Are indexes unnecessary for columnar database?

In a columnar database, are indexes unnecessary or useless?
2
votes
1answer
312 views

Any experience with cstore_fdw? [closed]

It looks like there is a (finally) an open source columnar and compression extension for Postgres. I wonder if anyone had any experience with it yet? I've worked with Greenplum for years, but I've ...
1
vote
1answer
218 views

what is the structure of a Mysql multi-column index? [closed]

For example: CREATE TABLE test( col_1 INT, col_2 INT, col_3 VARCHAR(11), col_4 VARCHAR(11) )ENGINE = INNODB; CREATE INDEX mul ON test(col_2,col_3,col_4); Sorry,my English is not good,I mean ...
1
vote
0answers
78 views

Coerce columnstore to operate in batch mode [closed]

I want to try the column store index in SQL Server and im trying to get my queries to run in batch mode, i rewrote my query this way( it had an outer join before) but the execution plan still show ...
0
votes
1answer
271 views

Storing 5TB web server access log vs OLAP DB

We have over 5TB compressed web server log in a HDFS and we often analyse using Hadoop. It is painful to run map reduce on 5TB of data and most importantly, not many developer are familiar with it. ...
2
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0answers
302 views

Best Practice to update columnstore indexed tables

I have a table with aprox. 22 Bn rows, for each month I have made one partition that and each partition has two data files. I created the columnstore index on this table and the performance ...
1
vote
1answer
1k views

IBM DB2 - store large files

I want to store large files in a DB2 database and I need more information about which is the best technique to use as I am new in this IBM product (previous experience with T-SQL only). The ...
6
votes
2answers
339 views

Does the order of columns in a columnstore index matter?

I have a table with ~200 million rows and ~15 columns in it. I am planning to create a COLUMNSTORE index on my table. Will there be any change in performance based on the order of columns that I use ...
7
votes
2answers
1k views

Database for building a realtime analytics system

I want to build a system similar to Google Analytics (only used for internal use, less traffic and less feature), and mainly focus on Real time counting of unique URI visit/PV by different ...
13
votes
1answer
1k views

What's the anatomy of a columnstore index?

One of the new features in SQL Server 2012 codenamed Denali is the Columnstore index. I know a good bit about regular old row-store indexes, like the b-tree structure, differences in storage between ...