PostgreSQL allows only one server encoding per database. It is therefore not possible for JSON to conform rigidly to the specification unless the server encoding is UTF-8. Attempts to directly include characters which cannot be represented in the server encoding will fail; conversely, characters which can be represented in the server encoding but not in UTF-8 will be allowed. \uXXXX escapes are allowed regardless of the server encoding, and are checked only for syntactic correctness.
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