Probabilistic Hash Table Deletion via Summary Buckets

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Solution Overview

Problem

Large hash tables can be time-consuming and processor-intensive to search through, especially when they exceed local memory limits, necessitating slower access memory and increasing search time, and existing solutions do not efficiently support dynamic insertion and deletion operations.

Innovation Solution

A method involving a summary table with buckets that track deletions using prefix, transit, and signature tables derived from hash values, allowing for efficient determination of entry existence and supporting deletion operations in a probabilistic data structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a large hash table is used to store more data, then the storage capacity is improved, but the search time increases and processor cycles become more intensive

Engineering Contradiction:
Improvestorage capacityVSAvoidsearch time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent divides the hash table into multiple levels (primary hash table, secondary hash tables) where the primary table stores only hashes and points to secondary tables that store actual data. This segmentation allows the system to maintain a large storage capacity while reducing search time by avoiding full-table scans and enabling more efficient lookup operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a hierarchical dimension to the traditional flat hash table structure. By adding a second level of hash tables, the system transforms a two-dimensional search problem into a multi-level structure that can be navigated more efficiently, reducing the search space at each level and overall search time.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Speed

If a large hash table is stored in local memory, then access speed is improved, but the memory requirements exceed local memory limits

Engineering Contradiction:
Improveaccess speedVSAvoidmemory volume
Core Design Contradiction:
SpeedVSVolume of stationary object

Solution Approach 1:

The patent segments the large hash table into a primary hash table that fits in fast local memory (storing only hashes) and secondary hash tables that can be stored in slower, larger capacity memory. This allows the system to maintain fast access for the most frequently accessed data while storing the complete large dataset in more economical memory.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different storage qualities to different parts of the data structure. The primary hash table uses fast local memory for immediate access, while secondary hash tables use slower but larger capacity memory for complete data storage. This local quality differentiation optimizes both speed and memory utilization.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If existing hash table solutions are used, then data storage is achieved, but dynamic insertion and deletion operations are not efficiently supported

Engineering Contradiction:
Improvedata storageVSAvoiddynamic operation efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The patent implements a dynamic hash table structure where buckets can be created, deleted, and reconfigured during operation. The system dynamically adjusts the hash table structure based on insertion and deletion operations, maintaining optimal performance for dynamic workloads rather than static data storage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent enables efficient deletion operations by allowing buckets to be discarded when empty and recovered when needed. This mechanism supports dynamic data structures where entries are frequently added and removed, improving productivity for applications requiring continuous updates.

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentUS20240362224A1Locating a value through deterministic searching
Publication Date: 2024.10.31 PURE STORAGE INC
  • US20240362224A1 patent drawing
  • US20240362224A1 patent drawing
  • US20240362224A1 patent drawing

AI summary

A method for efficiently supporting deletion in a probabilistic data structure, and related computing or storage system are described. A processor, computing system or storage system constructs a table and a summary table for determining whether there is an entry for a value in the table. The summary table has buckets pointed to by address fields of values. Each bucket has a prefix table, a transit table, signature table and a first indicator. The system tracks deletion and addition of items of the table and summary table through the first indicators.