New log fields and SQL query filter

Hello,

Where can I obtain more information about the log fields like: "logflag", "dsteuid", "dstepid", "sentdelta", "rcvddelta" ? What they mean? How they are calculated? What are the possible vaules?

I found in SQL queries something like: /*SkipSTART*/ and /*SkipEND*/ What are they used for?

Thanks.