Automatic table statistics collection policy.
自动表统计信息收集策略。
So for the table statistics, the CARD will show as 1,100,000.
因此对于表统计数据,CARD将显示为1,100,000。
Example 7: Collect catalog statistics on 3 specific indexes only (no table statistics).
示例7:只收集3个指定索引上的目录统计信息(不含表统计信息)。
Since the fragmented statistics are more granular than table statistics, they do take up more space as well.
因为片段统计比表统计更加细粒度,因此会占用更多的空间。
When enabled, automatic statistics collection helps improve database performance by ensuring that you have up-to-date table statistics.
启动时,动态统计数据集合可通过确保您拥有最新表统计信息来帮助提高数据库性能。
For example, refreshing of statistics can happen at fragment level, and fragment statistics can be added to, or removed from, table statistics.
例如,可以在片段级别上刷新统计数据,可以向表统计添加或从中移除片段统计。
If the compilation environment or table statistics have changed when the explain statement is issued, the compiler may generate a different access plan.
如果编译环境或表统计信息在explain语句执行时已经发生改变,那么编译器可能会生成一个不同的访问计划。
In this example, 10 percent of table data pages are used for the collection of table statistics, while for index statistics all of the index pages will be used.
本例中,10%的表数据页用于表统计信息的收集,而对于索引统计信息,将使用所有的索引页。
The automatic table statistics collection policy is used to control the behavior of automatic table statistics collection. The following elements are configurable.
自动表统计信息收集策略用于控制自动表统计信息收集的行为。
If your table statistics are up to date, you can quickly and inexpensively check the cardinality of the columns in your existing table by issuing the following statement.
如果表的统计信息是最新的,那么就可以通过如下语句快速检查现有表内列的基数。
Db2pd provides more than 20 options to display information about database transactions, table Spaces, table statistics, dynamic SQL, database configurations, and many other database details.
db 2 pd提供了20多个选项显示关于数据库事务、表空间、表统计信息、动态sql、数据库配置和其他很多数据库细节的信息。
Table 1 shows the rough statistics gathered for this article's sample scenario.
表1给出了本文的示例场景收集到的粗略统计。
In our first improvement to the benchmark, let us add an index on the bills table and update statistics for the table.
在我们对基准的第一个改进中,我们向账单表增加索引,并为表更新统计信息。
Also, an existing table has no statistics.
而且,现有表没有统计信息。
For ATTACH operation: fragmented statistics of the new fragment is built, and table level statistics is rebuilt from all fragmented statistics.
对于ATTACH操作:将对新的片段构建片段统计,并利用所有的片段统计重新构建表级统计。
For DETACH operation: table level statistics of the resulting tables are rebuilt from the fragmented statistics.
对于DETACH操作:生成的表的表级统计是使用片段统计重新构建的。
Perform this sequence of actions to enable both statistics summarized in Table 1.
执行操作序列以启用表1中总结的统计信息。
Inconsistent statistics may be caused when users collect the partial statistics, for example collecting table and index statistics individually, at different points in time.
用户只收集一部分数据可能会造成不一致的统计数据,例如,在不同时间分别收集表和索引统计数据。
This step takes the items array declared in the JSON and USES it to dynamically build an HTML table showing the statistics details.
该步骤接受JSON中声明的条目数组,使用它动态地构建一个显示统计信息细节的html表。
This example shows that if RUNSTATS is run while there is WRITE activity happening on the table, the statistics can be inconsistent as in this example.
该示例显示,如果在表上发生WRITE活动时运行RUNSTATS,统计数据就可能与本示例中的不一致。
Screen cap: Table showing statistics of executed statements.
屏幕图:执行的语句的统计数据。
The server can also efficiently rebuild table column statistics after ALTER FRAGMENT ATTACH or DETACH is executed.
服务器还可以在执行alterFRAGMENTATTACH或DETACH后有效地重新构建表列统计。
This command will ignore the STATCHANGE computation and rebuild all the table tab1 statistics.
该命令将忽略STATCHANGE计算并重建所有表tab1统计。
Notice that data from all fragments is sorted together to form table level statistics, which is encoded and stored in the system catalog sysdistrib.
注意,来自所有片段的数据被一同存储,形成了表级别的统计数据,被编码并存储到系统目录sysdistrib中。
Example 5: Collect catalog statistics on the table and indexes without distribution statistics.
示例5:收集表和索引上的目录统计信息,不包含分布统计信息。
Example 9: Collect catalog statistics on the table and indexes with distribution statistics
示例9:收集表和索引上的目录统计信息,包含分布统计信息
SYSSTAT views containing the table, column, and index statistics.
SYSSTAT视图,包含表、列和索引统计数据。
Example 10: Collect catalog statistics on the table and enhanced statistics on the indexes, as well as distribution statistics.
示例10:收集表上的目录统计信息以及索引上的详细统计信息,包含分布统计信息。
Example 12: Collect catalog statistics on only the table, with basic column statistics for deptno and deptname and distribution statistics on mgrno and admrdept.
示例12:只收集表上的目录统计信息,包含deptno和deptname上的基本列统计信息以及mgrno和admrdept上的分布统计信息。
Example 6: Collect catalog statistics on the table and enhanced statistics on the indexes, but without distribution statistics.
示例6:收集表上的目录统计信息以及索引上的详细统计信息,不包含分布统计信息。
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