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Why Is Data Inconsistent When SELECT Statements Without ORDER BY Are Used for Query in Distributed GaussDB?
Updated on 2024-03-08 GMT+08:00
Why Is Data Inconsistent When SELECT Statements Without ORDER BY Are Used for Query in Distributed GaussDB?
Symptom
Figure 1 There is no ORDER BY in SELECT statements.
Causes
In distributed GaussDB, data is evenly stored on each DN based on distribution keys. If ORDER BY is not specified in a SELECT query, data is randomly read from DNs. Therefore, data consistency cannot be ensured.
Solution
Use ORDER BY in SQL statements for query. The column followed by ORDER BY is the distribution key.
Figure 2 SELECT statements with ORDER BY
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