What is a columnstore index?

Columnstore indexes are the standard for storing and querying large data warehousing fact tables. This index uses column-based data storage and query processing to achieve gains up to 10 times the query performance in your data warehouse over traditional row-oriented storage.

When should I use a columnstore index?

Consider using a clustered columnstore index when: Each partition has at least a million rows. Columnstore indexes have rowgroups within each partition. If the table is too small to fill a rowgroup within each partition, you won’t get the benefits of columnstore compression and query performance.

Why does columnstore index dramatically improve performance on fact table data?

Columnstore indexes achieve up to 10x greater data compression than rowstore indexes. This greatly reduces the I/O required to execute analytics queries and therefore improves query performance. Columnstore indexes read compressed data from disk, which means fewer bytes of data need to be read into memory.

What are the considerations for implementing memory optimized or in-memory tables?

For details see Optimize Performance using In-Memory Technologies in SQL Database.

  • Ensure compatibility level >= 130.
  • Elevate to SNAPSHOT.
  • Create an optimized FILEGROUP.
  • Create a memory-optimized table.
  • Create a natively compiled stored procedure (native proc)
  • Execute the native proc.

What is columnstore index in SQL Server with example?

Columnstore index is a new type of index introduced in SQL Server 2012. It is a column-based non-clustered index geared toward increasing query performance for workloads that involve large amounts of data, typically found in data warehouse fact tables.

Why is clustered index faster?

On the other hand, with clustered indexes since all the records are already sorted, the SELECT operation is faster if the data is being selected from columns other than the column with clustered index.

What is memory optimized database?

A database can contain in-memory as well as disk-based objects. Rows in memory-optimized tables are versioned. This means that each row in the table potentially has multiple versions. All row versions are maintained in the same table data structure.

How many types of indexes are on memory optimized tables?

SQL Server 2014 (12. x) and SQL Server 2016 (13. x) have a limit of 8 indexes per memory-optimized table or table type.

What is columnstore SQL?

What are different types of database indexes?

Contents

  • 5.1 Bitmap index.
  • 5.2 Dense index.
  • 5.3 Sparse index.
  • 5.4 Reverse index.
  • 5.5 Primary index.
  • 5.6 Secondary index.
  • 5.7 Hash index.

How can we optimize a SQL query?

It’s vital you optimize your queries for minimum impact on database performance.

  1. Define business requirements first.
  2. SELECT fields instead of using SELECT *
  3. Avoid SELECT DISTINCT.
  4. Create joins with INNER JOIN (not WHERE)
  5. Use WHERE instead of HAVING to define filters.
  6. Use wildcards at the end of a phrase only.