Delete-Safe Compression Selection for Delta-Encoded Index Integers
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Solution Overview
Problem
Dictionary-based compression methods for delta encoded integers in database indexes may not ensure that the compressed index remains delete-safe, potentially leading to increased storage space requirements after row deletions, which can cause row deletion operations to fail.
Innovation Solution
A method to select a delete-safe compression algorithm by computing the maximum number of data values eliminated and the minimum size of delta encoded data values, determining a delete-safe threshold, and choosing the compression scheme that meets this threshold to ensure the index remains compact post-deletion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If dictionary-based compression method is applied to delta encoded integers, then compression ratio is improved, but delete-safety property deteriorates
Solution Approach 1:
The patent changes the parameter of compression method selection by introducing a delete-safety evaluation mechanism. Instead of arbitrarily choosing a compression method, the system computes the maximum number of data values eliminated by each compression algorithm and compares it against a delete-safe threshold value, selecting only those methods that meet the threshold criterion.
Solution Approach 2:
The patent performs preliminary evaluation of compression algorithms before actual compression is applied. By computing the maximum number of data values eliminated and comparing against the delete-safe threshold in advance, the system ensures delete-safety is maintained before committing to a compression method.
2Loss of substance
If compression algorithm eliminates more data values, then compression ratio is improved, but risk of exceeding delete-safe threshold increases
Solution Approach 1:
The patent implements a feedback mechanism where the system computes the maximum number of data values eliminated by each compression algorithm and feeds this information back into the selection process. This feedback is compared against the delete-safe threshold to determine whether the compression algorithm is suitable, creating a closed-loop decision system.
3Ease of manufacture
If arbitrary compression method is chosen, then implementation simplicity is improved, but index expansion after deletion occurs
Solution Approach 1:
The patent changes the selection criterion from arbitrary choice to parameter-based evaluation. By computing the maximum number of data values eliminated and comparing against the delete-safe threshold, the system objectively determines which compression methods are suitable, replacing subjective or arbitrary selection with a quantifiable parameter-based approach.
Data Source
AI summary
Techniques are disclosed for selecting a delete-safe compression method for a plurality of delta encoded data values (e.g., delta encoded integers or deltas). For example, a computer-implemented method for selecting an optimal delete-safe compression algorithm from among two or more compression algorithms for use on a plurality of delta encoded data values includes the following steps. The maximum number of data values eliminated by each of the two or more compression algorithms is computed. For the plurality of delta encoded data values to be compressed, the minimum size of the plurality of delta encoded data values before compression thereof is computed. A delete-safe threshold value is computed based on the minimum size of the plurality of delta encoded data values. Then, the compression algorithm is selected from the two or more compression algorithms that achieves the delete-safe threshold value.