-
Statistics for the table
-
Statistics for the indexes
-
Share level
-
OK
-
Show SQL
-
Cancel
Statistics for the table
Select one of the following radio buttons to specify whether and how you
want the table's statistics updated:
- Do not update
- Statistics for the table are not updated. Select this radio button
if you want to update statistics for only the table's indexes.
- Update without distribution statistics
- Basic-level statistics on the table data are updated in the system catalog
tables. An example of a basic-level statistic is the number of pages
being used by the table.
Distribution statistics on values in table columns are not
collected.
- Update with distribution statistics
- Basic-level statistics on the table data are updated in the system catalog
tables, and statistics on the distribution of data values in the table columns
are collected. The query optimizer uses these statistics to more
accurately estimate the number of rows in a column that satisfy given
equalities or ranges.
An example of a distribution statistic is the frequency with which a
particular data value occurs in a column.
Statistics for the indexes
Select one of the following radio buttons to specify whether and how you
want the table's indexes' statistics updated:
- Do not update
- Statistics for the table's indexes are not updated. Select
this radio button if you want to update statistics for only the table.
- Update without extended index statistics
- Basic-level statistics are collected on the indexes. An example of
a basic-level statistic is the number of index leaf pages.
- Update with extended index statistics
- Basic-level and detailed statistics are collected for the indexes.
The detailed statistics can help the optimizer better estimate the I/O cost of
an index scan.
An example of a detailed statistic is the number of I/Os that are needed to
read the data pages into buffer pools of various sizes.
Share level
Select one of the following radio buttons to choose what access other users
can have to the table while statistics are collected.
- Change (Table read/write allowed)
- Other users can read from and write to the table.
- Reference (Table read only)
- Other users have read-only access to the table.