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SQL Anywhere 10.0.1 » SQL Anywhere Server - SQL Reference » Views » System views in Sybase Central

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SYSCOLSTAT system view


The SYSCOLSTAT system view contains the column statistics, including histograms, that are used by the optimizer. The contents of this view are best retrieved using the sa_get_histogram stored procedure or the Histogram utility. The underlying system table for this view is ISYSCOLSTAT.

NOTE

If the database is encrypted, or if table encryption is enabled, the underlying system table, ISYSCOLSTAT, is also encrypted since it contains histogram information that could reveal underlying data.

Columns
Column name Column type Column constraint
table_id UNSIGNED INT NOT NULL
column_id UNSIGNED INT NOT NULL
format_id SMALLINT NOT NULL
update_time TIMESTAMP NOT NULL
density FLOAT NOT NULL
max_steps SMALLINT NOT NULL
actual_steps SMALLINT NOT NULL
step_values LONG BINARY
frequencies LONG BINARY

table_id    A number that uniquely identifies the table or materialized view to which the column belongs.

column_id    A number that, together with table_id, uniquely identifies the column.

format_id    For system use only.

update_time    The time of the last update of the column statistics.

density    An estimate of the average selectivity of a single value for the column, not counting the large single value selectivities stored in the row.

max_steps    For system use only.

actual_steps    For system use only.

step_values    For system use only.

frequencies    For system use only.

Constraints on underlying system table

PRIMARY KEY (table_id, column_id)

FOREIGN KEY (table_id, column_id) references SYS.ISYSTABCOL (table_id, column_id)