You can execute sp_updatestats which will update statistics for all tables of the current database, as you may have read dbcc reinex may be removed in next version so. SQL Server (starting with 2008). Runs UPDATE STATISTICS against all user-defined. For disk-based tables, sp_updatestats updates statistics based on the.
Contents • • • • • • • • • • Introduction Statistics contain information about the distribution of values in a particular index or columns of a table. You can create statistics using the CREATE STATISTICS statement or by using the sp_createstats command. Statistics track information about whether indexes have good or poor selectivity, which determines the effectiveness of an index for satisfying queries. SQL Server creates statistics automatically when you create indexes. In addition, SQL Server creates statistics for columns that do not have indexes defined on them, stored in the sysindexes table. Such statistics have a name starting with '_WA' and can be viewed using the following query: SELECT * FROM sysindexes WHERE name LIKE '%_wa%' Statistics are stored as a binary string, much like image data in the statsblob column of sysindexes. If SQL Server creates indexes on un-indexed columns, your application's performance is likely to benefit from adding indexes on such columns.
Note also that statistics on un-indexed columns count towards the upper limit of 249 non-clustered indexes per table. DBCC SHOW_STATISTICS Statistics for a particular index can be viewed using the DBCC SHOW_STATISTICS statement. The following table contains an explanation for each column of output: Column Explanation Updated Date and time when statistics were last updated Rows Total number of rows in the table Rows Sampled Number of rows used for sampling Steps Number of distribution steps Density Inverse of selectivity of the first index key Average Key Length Average length of the first index key All Density Inverse of selectivity of a combination of index keys Average Length Average length of a combination of index keys Columns Index keys - columns on which index is built. Specified for a combination of keys for which all density is displayed.
Range_hi_key Maximum value of a histogram step Range_rows Number of rows that are within the histogram step EQ_rows Number of rows that have an equal value as the maximum value in the histogram step Distinct_range_rows Number of distinct values in the histogram step Avg_range_rows Average number of duplicate (non-distinct) values within a histogram step As data rows are added, modified and removed from a table statistics become outdated. European Accident Statement Form Pdf there. Yugioh Card Maker Mac. If query optimizer does not have up-to-date statistical information about distribution of values it might use an index which is not very efficient for a particular query. Via Hd Audio Codec Drivers Windows Xp. You should ensure that statistics stay up-to-date, so that query optimizer makes intelligent decisions about using appropriate indexes.