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HeatWave User Guide  /  ...  /  VARLEN Encoding Limits

11.4.1.2 VARLEN Encoding Limits

  • The maximum size of VARLEN-encoded columns for base tables is 8000 bytes. For example, if using a 4-byte character set, a VARCHAR column is limited to 2000 characters (VARCHAR(2000)).

    TEXT-type values larger than 8000 bytes are rejected by table load and change propagation operations. Both operations fail with an error when encountering a TEXT-type value larger than 8000 bytes. (This limit is not enforced for VARLEN-encoded VARCHAR columns.)

  • The maximum size of VARLEN-encoded columns for final and intermediate results generated by HeatWave is 16382 bytes.

  • When a query includes VARLEN-encoded columns, the maximum number of columns produced by any physical operator is 128. However, the actual maximum number of columns depends on factors such as MySQL limits, protocol limits, the total number of columns, column types, and column widths (the string length of supported string-type columns). For example, for any physical operator, the maximum number of 8000-byte VARLEN-encoded columns is 31 if the query only uses VARLEN-encoded columns. The maximum number of 16382-byte VARLEN-encoded columns is 15. On the other hand, HeatWave can only produce a maximum of 128 VARLEN-encoded columns that are 1 byte in size if the query includes only VARLEN-encoded columns. If a query includes non-VARLEN-encoded columns, the column number limits are likely to be lower.

  • Only expressions with non-boolean types are supported.