src/Functions/FunctionsConversion.h:1728

• This per-row timezone lookup inside the conversion loop (line 1725) will override the timezone extracted at lines 1718-1723. However, Time64 does not support per-row timezones, so this logic appears incorrect. Either this should be removed, or if an explicit timezone argument is provided (arguments.size() > 2), it should be used instead of extracting from the source type, but applied once before the loop, not per-row.

                if (arguments.size() > 2 && !arguments[2].column.get()->getDataAt(i).toString().empty())
                    time_zone = &DateLUT::instance(arguments[2].column.get()->getDataAt(i).toString());

src/Functions/FunctionsConversion.h:1730

• The timezone lookup via DateLUT::instance() is performed inside the loop for every row, even when argument[2] is a constant column. For constant timezone arguments, this lookup should be hoisted outside the loop to avoid repeated lookups. Consider checking if arguments[2].column is a ColumnConst and extracting the timezone once before the loop.

                if (arguments.size() > 2 && !arguments[2].column.get()->getDataAt(i).toString().empty())
                    time_zone = &DateLUT::instance(arguments[2].column.get()->getDataAt(i).toString());

src/Functions/FunctionsConversion.h:1

• The scale multiplier calculation on line 1751 occurs inside the loop but produces the same value for all rows. This should be computed once before the loop starts (around line 1707 where the scale is determined) to avoid redundant calculations.

#pragma once

src/Functions/FunctionsConversion.h:1754

• [nitpick] The comment uses C-style comment syntax ('//'), which is inconsistent with the C++-style comment syntax ('///') used elsewhere in this file for documentation comments (see lines 1758, 240, 401, 681). For consistency with the codebase style, use '///' for documentation comments.

                // Get the UTC seconds (the integer part) from the input value