pattern string escape all the string.

[jianhe-fun]

in postgres, you can $$ this is your string $$.
between $$, except $, what you enter is really what is, literal string. You don't need escape special character.

in regex there are so many special characters. Would be better to escape it once for all.
is there any way to do it in rg. so I don't need think about special character.

[BurntSushi]

Yes. The -F/--fixed-strings flag. For example, rg -F '+' is equivalent to rg '\+'.

[jianhe-fun]

then the following should not yield any error, since all special character already escaped, if I specified --fixed-strings

rg --fixed-strings 'substring(ln,'(?:Execution Time:\s)([0-9.]*)')'

[BurntSushi]

Right. It won't return an error. The string will be searched as a literal. So for example, (?: will literally match (?:.

[jianhe-fun]

in postgres world, would be
rg $$substring(ln,'(?:Execution Time:\s)([0-9.])')$$.
it will match the literal string: substring(ln,'(?:Execution Time:\s)([0-9.])')

[BurntSushi]

Okay? Are you asking a question?