Statistics per Dimension
Statistics for the Whole Database
The following MaxL statement
query database asoapp.asodb list aggregate_storage runtime_info;
returns output which includes the following lines
parameter value +--------------------------------------------+-------------------------------------------- Dimension [Year] has [3] levels, bits used 4 Dimension [Measures] has [1] levels, bits us 4 Dimension [Product] has [3] levels, bits use 5 Dimension [Market] has [3] levels, bits used 5 Dimension [Scenario] has [1] levels, bits us 2 ...
For each dimension, the following statistics are shown:
Each cell in an aggregate storage database is stored as a key/value pair. The key length is 8 bytes or a multiple of 8 bytes; for example, 8, 16, 24.
Each key corresponds to a numeric value in the database. The statistics shown above report key lengths in bytes and the number of bits used per key. How many bits each dimension uses in the dimensional key is shown in the value column for each dimension.
How many bits used in each key may amount to less than the bytes needed for physical storage of the key. As an example where this knowledge might be useful, consider a case in which a key is using 65 bits. If you can reduce the key length by one bit to 64, then you can have then key length be 8 bytes instead of 9, an improvement which reduces the overall size of the databse. Another use for these statistics might be to examine them to see how much you gain from removing any particular dimension.
The same MaxL statement used above also returns the following lines in its output:
parameter value +--------------------------------------------+-------------------------------------------- ... Max. key length (bits) 20 Max. key length (bytes) 0 Number of input-level cells 0 Number of aggregates 0 Number of aggregate cells 0 Size of the input level data (KB) Size of the aggregate data (KB)
Column Name | Description |
---|---|
Max. key length (bits) |
The sum of all the bits used by each dimension. For example, there are 20 bits in the key used for dimensions, and the first 4 are used by Year. |
Max. key length (bytes) |
How many bytes the key uses per cell. |
Number of input-level cells |
The number of existing level-0 cells in the database. |
Number of aggregates |
The number of aggregate views in the database. |
Number of aggregate cells |
The number of cells stored in the database's aggregate views. |
Size of the input level data (KB) |
The total disk space used by input-level data. |
Size of the aggregate data (KB) |
The total disk space occupied by aggregate cells. |
For input-level and aggregate cells, the above statistics show
Because Analytic Services uses compression, these statistics are useful because it is not always possible to derive disk size based on the number of cells.
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