ROWS_AT_A_TIME

ROWS_AT_A_TIME is set by default to 1000, and retrieves results as blocks of rows of that size. The column formatting for the first block is used for all blocks, so in later blocks some entries could overflow.

When formatting results, Vertica buffers ROWS_AT_A_TIME rows in memory to calculate the maximum column widths. It is possible that rows after this initial fetch are not properly aligned if any of the field values are longer than those see in the first ROWS_AT_A_TIME rows. ROWS_AT_A_TIME can be unset with vsql meta-command\unset to guarantee perfect alignment. However, this requires re-buffering the entire result set in memory and might cause vsql to fail if the result set is too big.