Does squatter retry on transient errors (xapian)?

[Dilyan Palauzov]

Hello,

https://fastmail.blog/2014/12/01/email-search-system/ says:

The process is as follows:
5. if the xapianactive file has changed, discard all our work (we lock  
against this, but it's a sanity check) and exit

Does squatter exit with an error message in this case, and has to be  
started again, or does it retry automatically, until it successes?

What means “indexing”?  -T can be passed to squatter only in compact  
mode, and is a directory for temporary files.  But the documentation  
says, this directory is used when “indexing”.  How big is the data  
stored there?  Lets say if tier A allocates K MB for its data, and  
tier B allocates L MB for the data, is during compacting of A and B  
approximately K+L MBs used in the temporary directory?

Regards
   Дилян