As part of continuous improvement of the quality of SQL Server, we add new tests to stress the features in various ways. We recently discovered a corruption issue in clustered columnstore index in SQL Server 2014 as part of new stress tests. After analyzi...
You have Microsoft SQL Server 2014 installed on a computer. You have poorly configured disk caching or failed raid setup, or both. This results in an inconsistent cache state. You run the query DBCC CHECKTABLE ag...
This article discusses a problem that occurs during a query of a clustered columnstore index in Microsoft SQL Server 2014. This article providesa resolutionto this problem. Summary When you use a query that scans a clustered columnstore index...
index cci clustered columnstore ); This is equivalent to collections that you might find in classic NoSQL database because they store each JSON document as a single entity and optionally create indexes on these documents. The only difference is CLUSTERED COLUMNSTORE index on this table that prov...
For more information, see What's New in Columnstore Indexes. Examples A. To check for ordered columns and order ordinal: SQL Copy SELECT object_name(c.object_id) table_name, c.name column_name, i.column_store_order_ordinal FROM sys.index_columns i JOIN sys.columns c ON i.object_id ...
(one per core) targeting the same table We did a trickle load test on a single thread whereby we inserted 3.93 million rows, one at a time in independent transactions, into an empty column store index. This was done on a machine with 4 cores and 8 hardware threads. The test w...
In the next step, let’s check how large delta store affects performance of the queries. For that test, I inserted one million rows to the table using small batches and run the test query. After that, I rebuilt the columnstore index, comparing the execution time of the test query before...
Use this procedure to estimate the amount of space that is required to store data in a clustered index in SQL Server.
AlterTableAlterColumnStatement AlterTableAlterIndexStatement AlterTableAlterPartitionStatement AlterTableChangeTrackingModificationStatement AlterTableConstraintModificationStatement AlterTableDropTableElement AlterTableDropTableElementStatement AlterTableFileTableNamespaceStatement AlterTableRebuildStatement AlterTabl...
SQL Server cannot seek a RID directly on the heap. This behavior can be acceptable when the table is small. When not to use a heap Do not use a heap when the data is frequently returned in a sorted order. A clustered index on the sorting column could avoid the sorting operation. Do ...