Symptoms When you try to build an index (by using CREATE INDEX or ALTER INDEX) on a spatial data type of a large table, Microsoft SQL Server 2012 or SQL Server 2014 may perform poorly. You can find many spinlock contentions on SOS_CACHESTORE and SOS_SELIST_SIZED_SLOCK. Resolution The ...
CREATE TABLE geom (g GEOMETRY NOT NULL, SPATIAL INDEX(g)) ENGINE=MyISAM; With ALTER TABLE: ALTER TABLE geom ADD SPATIAL INDEX(g); With CREATE INDEX: CREATE SPATIAL INDEX sp_index ON geom (g); SPATIAL INDEX 创建了一个R-tree 索引。对于支持非空间索引的存储引擎,引擎创建一个B-tree索引. B...
When an index exists on one or more columns of a table, the database can in some cases retrieve a small set of randomly distributed rows from the table. Indexes are one of many means of reducing disk I/O. If a heap-organized table has no indexes, then the database must perform aful...
CREATESPATIALINDEXindex_nameON(spatial_column_name) {<geometry_tessellation>|<geography_tessellation>} [ON{filegroup_name|"default"} ] [;]::={database_name.schema_name.table_name|schema_name.table_name|table_name}<geometry_tessellation>::={<geometry_automatic_grid_tessellation>|<geometry_manual_...
Moran’s index is an important spatial statistical measure used to determine the presence or absence of spatial autocorrelation, thereby determining the selection orientation of spatial statistical methods. However, Moran’s index is chiefly a statistica
Modifies an existing table or view index (rowstore, columnstore, or XML) by disabling, rebuilding, or reorganizing the index; or by setting options on the index.
Ranking of years based on Drought Persistency Score (DPS) indicated that 1987 was the most severe drought year in the country. The results of the study have revealed various aspects of drought climatology in India. A similar analysis with the SPI of finer spatial resolution and relating it to...
Custom Data Ranges (Optional) The possible minimum and maximum values that will be used in the units of the variables. Each variable will be scaled between 0 and 1 based on the possible minimum and maximum values. Value Table Thresholds (Optional) The threshold that determines whether a f...
CREATE XML INDEX CREATE SPATIAL INDEX CREATE COLUMNSTORE INDEXTransact-SQL 構文表記規則構文SQL Server、Azure SQL Database、Azure SQL Managed Instance の構文syntaxsql コピー CREATE [ UNIQUE ] [ CLUSTERED | NONCLUSTERED ] INDEX index_name ON ( column [ ASC | DESC ] [ ,...n ] ) [ I...
指定应用 DATA_COMPRESSION 或XML_COMPRESSION 设置的分区。 如果未对索引进行分区,则 ON PARTITIONS 参数将生成错误。 如果未提供 ON PARTITIONS 子句,DATA_COMPRESSION 或XML_COMPRESSION 选项将应用于已分区索引的所有分区。可以通过下列方式指定 <partition_number_expression>:提供分区号(例如:ON PARTITIONS (2))。