Metadata Cache Prefetching for Query Latency and Network Overhead

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Solution Overview

Problem

Existing data processing services face challenges in efficiently retrieving and caching object metadata from remote data sources, leading to increased network overhead, query load on remote sources, and potential inconsistencies between metadata caches and remote data sources.

Innovation Solution

The implementation of a system that utilizes a metadata cache to store prefetched metadata information, allowing for the identification of metadata corresponding to query operations. This system determines whether the metadata meets an update condition, fetching updated metadata from the remote data source and storing it in the cache when necessary, thereby reducing the need for frequent metadata retrieval during query operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metadata is frequently retrieved from remote data sources during query operations, then query accuracy and consistency are improved, but network overhead and query load on remote sources increase

Engineering Contradiction:
Improvemetadata consistencyVSAvoidnetwork overhead
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system performs preliminary action by prefetching metadata from remote data sources and storing it in a metadata cache before actual query operations occur. This allows the data processing service to serve query metadata requests from the local cache, reducing network overhead and query load on remote sources while maintaining metadata consistency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The metadata cache acts as an intermediary between the data processing service and remote data sources. It stores copies of metadata locally, allowing the service to retrieve metadata without directly querying remote sources for every operation, thereby reducing network overhead while maintaining data consistency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If metadata is cached locally to reduce network overhead, then network overhead and query load are reduced, but metadata inconsistency between cache and remote sources may occur

Engineering Contradiction:
Improvenetwork overheadVSAvoidmetadata consistency
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system implements periodic action by establishing a background process that periodically monitors and detects changes in remote data sources. When changes are detected, the metadata cache is automatically updated to reflect the current state, ensuring consistency while minimizing network overhead by only updating when necessary.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses feedback mechanisms where the data processing service monitors query patterns and metadata usage. Based on this feedback, it intelligently determines when to prefetch and cache metadata, and when to update the cache, optimizing the balance between network overhead and metadata consistency.

Inventive Principle:
Principle #23Feedback

3Loss of time

If metadata is prefetched and cached for all data objects, then query latency is reduced, but system complexity and memory usage increase

Engineering Contradiction:
Improvequery latencyVSAvoidcache management complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The system applies partial action by selectively prefetching and caching metadata based on actual query patterns and usage requirements. Instead of caching all metadata unconditionally, it caches only the metadata that is likely to be needed, reducing memory usage and cache management complexity while still achieving low query latency for relevant operations.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS20250156397A1Retrieval and caching of object metadata across data sources and storage systems
Publication Date: 2025.05.15 DATABRICKS INC
  • US20250156397A1 patent drawing
  • US20250156397A1 patent drawing
  • US20250156397A1 patent drawing

AI summary

A system for retrieving and caching metadata from a remote data source is described. The system may receive a request from a client device. The request is to perform a query operation on a set of data objects stored in the remote data source. The system may access a metadata cache storing metadata information on one or more data objects of the remote data source and identify metadata corresponding to the set of data objects for the query operation in the metadata cache. The system may determine whether the identified metadata for the set of data objects meets an update condition. In response to the identified metadata meeting the update condition, the system may fetch updated metadata for at least the set of data objects from the remote data source, and store the updated metadata in the metadata cache.