sql server columnstore index

What is an index? Take the directory pages (indexes) of the Chinese dictionary for example: just as the Chinese characters in the Chinese Dictionary are stored by page, the data records in SQL Server are also stored by PAGE, and the size of each page is generally 4 K. To speed up searching, Chinese characters (words) are usually sorted by pinyin, strokes, radi

What is an index Take the table of Contents page of Chinese dictionary (index) metaphorically: Just as Chinese characters are stored as pages in a dictionary, data records in SQL Server are stored on a per-page basis, typically 4K in volume. In order to speed up the speed of the search, the Chinese word (word) code gen

page is dedicated to the allocation and management of data spaces, including: PFS pages (page free space): Record whether a page is assigned, in a mixed or consistent extension, and how much space is available on the page; Gam page (Global allocation MAP) and Sgam page (secodary Global allocation map): Used to record the location of an idle extension or a mixed extension containing free pages. Sqls Comprehensive utilization of these three types of paging files creates a new space for the data t

Label:The leaf page of a clustered index stores the table's data. As a result, table rows are physically sorted by clustered index columns, because table data can only have one physical order, so a table can have only a single clustered index. When we create a PRIMARY key constraint, if there is no clustered index and

Tags: style using file data ar problem time line　　SQL Server index structure and its use (i)FreedkFirst, understand the index structure in a comprehensible senseIn fact, you can interpret an index as a special kind of directory. Microsoft's

Tags: style blog color ar using SP data div onWhat is the index of the Chinese Dictionary of the Directory page (index) analogy: Just as Chinese characters are stored by page, the data records in SQL Server are stored on pages, and the capacity of each page is typically 4K. In order to speed up the search, Chinese word

Is null and is not null in SQL SERVER cause index failure ?, Sqlnull In fact, there is nothing to say about this problem. I encountered an SQL statement during optimization today. Because it is interesting, I have cut and simplified the SQL statement and demonstrated it for

What is an index? Take the directory pages (indexes) of the Chinese dictionary for example: just as the Chinese characters in the Chinese Dictionary are stored by page, the data records in SQL Server are also stored by PAGE, and the size of each page is generally 4 K. To speed up searching, Chinese characters (words) are usually sorted by pinyin, strokes, radical

the disk's head movement. Conversely, if their physical storage order is consistent with the logical order, SQL Server can read it one time because it reads a block (8 pages) at a time. Well, when we get to the basics, we'll see what is fragmentation.What is index fragmentationIndex fragmentation can be divided into two categories: internal

Tags: naming bin Sch clustered User Web page binding modeling altfirst, the basic concept of indexed views An indexed view is actually a view that "materialized" a set of unique values into a clustered index, which is materialized almost as a table, and its data is stored in one copy (it consumes hard disk space, but the query is fast, for example, you can set count (), sum () in an indexed view). The advantage is that it provides a very quick way to

Technical preparationBased on SQL Server2008R2, Microsoft uses a simpler case Library (Northwind) for parsing.IntroductionThe so-called index application is in our daily write T-SQL statement, how to use the existing index, then analysis is what we write query conditions, in fact, most of the situations are nothing mor

', UNION allSELECT 10002, ' NULL ', 24CREATE INDEX idx_test_n2 on TEST (name,age);UPDATE STATISTICS TEST with FULLSCAN;If the predicate is located in the Union index and not in the first column, is null or is the NOT NULL will not go index it?As shown above, it changes from an index lookup to an

is an internal method of SQL Server orchestration data. It provides a way for SQL Server to orchestrate query data what is an indexTake the Catalogue page (index) of the Chinese dictionary for example: Just as Chinese characters are stored on pages, the data records in

Tags: style color using strong data reWhat is an indexTake the catalogue page of the Chinese Dictionary (index) analogy: Just as Chinese characters are stored on pages, SQL Server data records are also stored on a per page basis, and each page capacity is typically 4K . In order to speed up the search, Chinese word (word) code generally have by pinyin, strokes, r

SQL Server INDEX OPTIMIZATION Clustered Index , The data stored in the table is stored in the order of indexes. , Higher retrieval efficiency than normal indexes , However, data is added / Modify / The deletion has a large impact. Non-clustered Index , The data storage

the clustered index occupies a larger space. 2. It takes time to create and maintain indexes. This time will increase as the data volume increases. 3. When you add or modify a record to a data table that contains an index, SQL server modifies and maintains the corresponding index