field store is a new type of index for the SQL Server engine. The field storage index is supported by a new data architecture called VERTIPAQ, which is designed to achieve significant performance improvements relative to the regular index.
In a regular
name of the table on which the index is created. View: Specifies the name of the view that created the index. ASC| = fillfactor: Used to specify that the data for each index page is a percentage of the index page size when the index is created, and the value of FILLFACTOR
Label:The original: SQL Server Tour--the third stop for those who have been on the back of a multi-year clustered indexWhen it comes to clustered indexes, I think every yard knows, but there are a lot of rustic programmers like me that can only use rote memorization to solve this problem, what table can only build a clustered index,Then it pulls in a directory se
Many people may confuse PrimaryKey with clustered index, or think this is the same thing. This concept is very incorrect. A primary key is a constraint attached to an index. This index can be a clustered index or a non-clustered index. So on one (or a group) Field
Many peopl
Because we often need to process a large number of tables, it is basically normal to view the table structure, data volume, and indexes, but the database in the production environment does not allow us to access directly, therefore, if you want to know the table structure and index information of the database in the production environment, you need to contact DBA frequently. To view the data volume of a specific table, use select count (1) the efficie
SQL Server Index Structure and usage (4)Author: freedk
I. An in-depth understanding of the index structureIi. Improve SQL statementsIii. General paging display and storage process for small data volumes and massive data
Importance of clustered
SQL Server Index Structure and usage (4)Author: freedk
I. An in-depth understanding of the index structureIi. Improve SQL statementsIii. General paging display and storage process for small data volumes and massive data
Importance of clustered
When SQL Server accumulates a certain amount of data, the query efficiency is often sharply reduced, which is often intolerable. At this time, we will think of various methods to optimize the system. DBCC is a group of powerful console commands, which are often used by DBCC dbreindex. It can help us recreate the index of a specified table to improve the query spe
Label:There are two tables in the DW, nonclustered ColumnStore Index is created on littletable and bigtable,bigtable, and the two tables are queried, such as the scirpt below. In the query, Waittype:htmemo and Htbuild appear, the query speed is extremely slow, more than 10 hours can not produce results. Select a few columns,,,
from with (nolock)
Inner Join with (nolock)
on Lt. Int_col1=or Lt. Int_col2=bt. Int_col4 I modified the query condi
date not NULL,
CONSTRAINT pk_data_rowid
PRIMARY KEY CLUSTERED (RowID)
);
Add 100,000 test data
Use TSQL2012
go
INSERT dbo. TestData with (Tablockx)
(somevalue, StartDate)
SELECT
CAST (n.n as VARCHAR (max)) + ' Jeffckywang ',
DATEADD (Day, (n.n-1)%, ' 20140101 ') from
dbo. Nums as N
WHERE
n.n >= 1 and
N.N
If we need to get somevalue = ' Jeffckywang ' in the table testdata, we want to create a nonclustered index on
for ordinary indexing, the main reason is that the ordinary index to the search conditions can only be precisely matched, and the text content in big fields, and usually do not perform exact text matching query on this field, but more is based on the keyword full-text search query, such as you look up an article information, Instead of typing the entire article into a query (if you have an entire article), you'll just type in some keywords. The full-
Before opening a text, let's start with a few concepts.
"Overwrite Query"
When an index contains all the columns that a query references, it is often referred to as an "overwrite query."
"Index Overlay"
If the returned data column is contained in the key value of the index, or is contained in the key value of the indexed key value + clustered
I believe everyone has some knowledge about SQLServer full-text indexing. The following describes the usage and related statements of SQLServer full-text indexing, we hope that you will have a better understanding of SQLServer full-text index. The code for copying is as follows: -- 1. Enable execfull-Text Index EXECsp_fulltext_databaseenable for the database -- 2. Create
I believe everyone has some knowledg
Query whether a table exists:In practice, you may need to delete a table. before deleting a table, you are advised to check whether the table exists to prevent returning error messages. In SQL Server, you can use the following statement: If object_id (n'table name', n'u') is not null drop table name; note, differences between common tables and temporary tables: If you want to delete DBO from the test databa
Tags: www color dex exe should see column query add Author Jonathan Allen, translator Sherry A new feature of SQL Server 2016 is the ability to add Columnstore Index (Columnstore Index) on memory-Optimized tables (Optimized table). To understand what this means, we should first interpret the term Columnstore
The current index structure for SQL Server is as follows:This is the storage form of the clustered index:Nonclustered indexes are in the following ways:They are stored in the data structure of a B + tree.I believe we have seen similar graphs, but there is no intuitive understanding, the following is a practical example to illustrate the structure of the graph.
more indexes, use SYS. indexes.
Important:
The fill factor setting is applied only after the index is created or re-generated. The SQL Server database engine does not dynamically retain the specified percentage of available space on the page. If you try to keep extra space on the data page, it will be back to the intention of using the fill fac
' + t.idxtypedesc COLLATE Latin1_general_ci_as_ks_ws +N ' INDEX ' + t.idxname COLLATE Latin1_general_ci_as_ks_ws +N ' on ' + t.objname COLLATE Latin1_general_ci_as_ks_ws +N ' (' + case when t.colsinc are NULL thenT.cols COLLATE Latin1_general_ci_as_ks_wsELSE--replace (Cols,t.colsinc, ') COLLATE Latin1_general_ci_as_ks_wsSUBSTRING (Cols,len (colsinc) +2,len (cols)-len (colsinc))END+ N ') ' +case when t.colsinc are not NULL and then ' INCLUDE (' +t.col
Brief introduction
The column storage index already exists in SQL Server 2012, but only nonclustered column indexes are allowed in SQL Server 2012, which means that the column index refers to the underlying data on the original r
I. Necessity:
MajoritySQL ServerThe table needs to be indexed to speed up data access. If no index is available,SQL ServerYou need to scan the table to read every record in the table to find the requested data. Indexes can be divided into cluster indexes and non-cluster indexes. Cluster indexes increase the data access speed by rearranging the data in the table, while non-cluster indexes increase the data
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