Usually, Essbase calculates a BSO cube in one calculation pass-through, and each of the required data blocks is read into memory only once, then calculated and saved. However, in some situations, Essbase may need to perform multiple calculation passes. On subsequent passes, Essbase brings data blocks back into memory, performs further calculations on them, and saves again.

When you perform a default, full calculation of a database (CALC ALL), Essbase attempts to calculate the database in one pass. If you have dimensions that are tagged as accounts or time, Essbase may have to do multiple calculation passes through the database.

The following table shows the number of calculation passes Essbase performs if you have dimensions that are tagged as time or accounts, and you have at least one formula on the accounts dimension:

If you are using formulas that are tagged as Two-Pass, Essbase may need to do an extra calculation pass to calculate these formulas.

When you use a calculation script to calculate a database, the number of calculation passes Essbase needs to perform depends upon the calculation script.

Essbase writes to the application log the calculation order of the dimensions for each pass, and how many cycles through the cube were performed.

For each block, Essbase decides whether to do a dense or a sparse calculation, depending on the type of values in the block. When you run a default calculation (CALC ALL), each block is processed in order, according to its block number.

Essbase calculates the blocks using this procedure:

• If you have Intelligent Calculation turned on, and if the block does not need to be calculated (if it is marked as clean), Essbase skips the block and moves to the next block.

• If the block needs recalculating, Essbase checks to see if the block is a level 0, an input, or an upper-level block.

• If the block is a level 0 block or an input block, Essbase performs a dense calculation on the block. Each cell in the block is calculated.

• If the block is an upper-level block, Essbase either consolidates the values or performs a sparse calculation on the block.

  The sparse member combination of each upper-level block contains at least one parent member. Essbase consolidates or calculates the block based on the parent member’s dimension. For example, if the upper-level block is for Product -> Florida from the Sample.Basic database, then Essbase chooses the Product dimension.

  If the sparse member combination for the block has multiple parent members, Essbase chooses the last dimension in the calculation order that includes a parent member. For example, if the block is for Product -> East, and you perform a default calculation on the Sample.Basic database, Essbase chooses the Market dimension, which contains East. The Market dimension is last in the default calculation order because it is placed after the Product dimension in the database outline. See Member Calculation Order.

  Based on the chosen sparse dimension, Essbase either consolidates the values or performs a sparse calculation on the block:

  • If a formula is applied to the block member on the chosen sparse dimension, Essbase performs a formula calculation on the sparse dimension. Essbase evaluates each cell in the block. The formula affects only the member on the sparse dimension, so overall calculation performance is not significantly affected.

  • If the chosen sparse dimension is a default consolidation, Essbase consolidates the values, taking the values of the previously calculated child blocks.