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Израиль начал наземную операцию на юге Ливана14:50
，详情可参考新收录的资料
// Use it directly
The first two requirements (“Efficient” and “Fine-grained”) are important for performance. Imagine a large spreadsheet with millions of cells containing formulas — it would be a huge waste of resources to recalculate every single cell, every time any input changes. Similarly, you don’t want to calculate the value of a cell multiple times if you can help it. In general, we want to do the minimum amount of work possible.
。新收录的资料对此有专业解读
This creates two distinct problems:
PostgreSQL Statistics: Why queries run slow，更多细节参见新收录的资料