Unverified50% confidenceFactExact time
The column order of a composite index is crucial, as the leading column determines which query patterns the index can efficiently support; an index beginning with customer_id can support queries filtering only by customer, but may not efficiently support queries filtering only by status.
1
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50%
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Long-term
Relevance
10/13/2026
First Seen
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Related Claims
UnverifiedA covering index contains all the information needed for a specific query, potentially allowing the database to avoid accessing the underlying table for each matching row; PostgreSQL can perform index-only scans when visibility information allows.71% similarUnverifiedQuery层的查询针对Ontology中的对象和关系,而非通过SQL直接操作底层表和字段,支持过滤、聚合、检查和沿关系链追溯71% similarUnverifiedThe same classification configuration can be reused in scenarios such as lead scoring, order categorization, and content moderation.70% similarUnverifiedSelectivity refers to the ratio of the number of distinct values in a column to the total number of rows; indexes on highly selective columns (such as email or order number) can quickly filter out large numbers of rows, while indexes on low-selectivity columns (such as gender or status flags) yield limited benefit, and a sequential scan may be faster.69% similarUnverifiedThe N+1 problem occurs when an application retrieves a set of records and then performs additional queries for associated entities; adding an index can speed up each lookup, but it cannot eliminate excessive database round trips.69% similar
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