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Index on integer field in PostgreSQL - code-flow.club | Q&A

Index on integer field in PostgreSQL


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10 views

There


PTS. big sign that PostgreSQL create a field of type integer + a btree index on the field.
Most of the values in the default field.

What you need


To select rows sorted by the given field.

Questions

  • What default value will run faster NULL or 0?
  • The same, in relation to the character(n) NULL or "?
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2 Answers

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I don't think you will feel the difference in speed between NULL and some value. And, by the way, you can easily check for this simple test.
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Asked the same question.
Generate a little data and verify whether the index of the query WHERE IS NULL ( I think 80% NULL will be fine)
If the plan shows the use of the index — so the index contains links to ALL of the NULL values, and, accordingly, there is no difference.
It would be interesting to create a sometimes compact codes for "sparse" values, where the references to NULL values are not stored, but usually in this case make the relationship one-to-one with another table.
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