sa_index_levels system procedure

Assists in performance tuning by reporting the number of levels in an index.

Syntax 
sa_index_levels( 
[ tbl_name 
[, owner_name ] ] 
)
Arguments

  • tbl_name   Use this optional CHAR(128) parameter to specify the table name.

  • owner_name   Use this optional CHAR(128) parameter to specify the owner name.

Result set
Column name Data type Description
TableName CHAR(128) The name of a table.
TableId UNSIGNED INTEGER The table ID.
IndexName CHAR(128) The name of an index.
IndexId UNSIGNED INTEGER

The index ID. This column contains one of the following:

  • 0   for primary keys

  • SYSFKEY.foreign_key_id   for foreign keys

  • SYSIDX.index_id   for all other indexes

IndexType CHAR(4) The index type. This column contains one of the following values:

  • PKEY   for primary keys

  • FKEY   for foreign keys

  • UI   for unique indexes

  • UC   for unique constraints

  • NUI   for non-unique indexes

Levels INTEGER The number of levels in the index.
Remarks

The number of levels in the index tree determines the number of I/O operations needed to access a row using the index. Indexes with a small number of levels are more efficient than indexes with a large number of levels.

The procedure returns a result set containing the table name, the table ID, the index name, the index ID, the index type, and the number of levels in the index.

If no arguments are supplied, levels are returned for all indexes in the database. If only tbl_name is supplied, levels for all indexes on that table are supplied. If tbl_name is NULL and an owner_name is given, only levels for indexes on tables owned by that user are returned.

Permissions

DBA authority required

Side effects

None

See also
Example

The following example uses the sa_index_levels system procedure to return the number of levels in the Products index.

CALL sa_index_levels( );
TableName TableId IndexName ... Levels
Products 436 Products ... 1
... ... ... ... ...
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