logtime function exception safe

[elliVM]

Description

Logtime function throws exception in case functions fail, forcing the SQL engine to be run in a throw no exceptions mode.
This change aims to allow the logtime function to use SQL null when parsing is not possible.

• Extracts the logtime function into it's own object for easier unit testing
• Checks if parse is available, otherwise uses SQL null

[kortemik]

making 1970 as a magick value is not really an option, better way would be to return a "sql null" in case extraction is not possible.

using

SELECT REGEXP_REPLACE(         '2010/01-08/sc-99-99-14-40/f17_v2/f17_v2.logGLOB-2010011601.log.gz','^\\d{4}\\/\\d{2}-\\d{2}\\/[\\w\\.-]+\\/([^\\p{Z}\\p{C}]+?)\\/([^\\p{Z}\\p{C}]+)(-@)?(\\d+|)-(\\d{4}\\d{2}\\d{2}\\d{2}).*',         '\\5' );
REGEXP_REPLACE(         '2010/01-08/sc-99-99-14-40/f17_v2/f17_v2.logGLOB-2010011601.log.gz','^\\d{4}\\/\\d{2}-\\d{2}\\/[\\w\\.-]+\\/([^\\p{Z}\\p{C}]+?)\\/([^\\p{Z}\\p{C}]+)(-@)?(\\d+|)-(\\d{4}\\d{2}\\d{2}\\d{2}).*',         '\\5' );

for example would provide better results. we should rather check that if extraction was successful and that it parses to date and then to unix date.

these can be verified with if(value regex 'valid value', unixtime(value), null) style

[elliVM]

refactored to check for valid timestamp, otherwise returning SQL null

[elliVM]

rebased

[Tiihott]

Logtime is handled as sql null when the value extraction is not possible. Tests pass and seem fine.
LGTM

[elliVM]

rebased

[kortemik]

select REGEXP_REPLACE(path, '^(?>.*-)([0-9]{4})([0-9]{2})([0-9]{2})([0-9]{2})(?>\..*)$', '\\1-\\2-\\3T\\4') from logfile;

[elliVM]

select REGEXP_REPLACE(path, '^(?>.*-)([0-9]{4})([0-9]{2})([0-9]{2})([0-9]{2})(?>\..*)$', '\\1-\\2-\\3T\\4') from logfile;

added

[elliVM]

rebased

[elliVM]

rebased

[Tiihott]

LGTM