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Sep 16, 2025 · Databases

Why Oracle VARCHAR2 Fails at 4000 Bytes and How to Fix It

This article analyzes a real‑world OceanBase‑to‑Oracle incremental sync failure caused by VARCHAR2 length limits, explains the role of NLS_LENGTH_SEMANTICS and MAX_STRING_SIZE, and provides three practical solutions—including extending string size, using CLOB fields, and PL/SQL workarounds—to reliably insert data exceeding 4000 bytes.