Hi. Here are some answers, although you may have already figured them out.
>> How to quick continue spidering/indexing after break?
If spidering ends prematurely, there may be index info remaining in the tempspider table. If so, just enter the URL again or choose the site and update.
>> The site is locked - I m able to unlock it in admin, but what next ?
See above.
>> But spidering sites takes too long - about 400 pages - 24 hours and it takes longer and longer.
Is it regular ?
Maybe update to version 1.8.1 or make sure that the tempspider table is empty between runs. To empty the tempspider table, just click the delete button
without selecting a site.
>> Is is nescessary to work with database.
Some people using Win/IIS servers have had to fiddle with the database tables, but if you are using Apache, then it shouldn't be necessary to work directly with the tables.
>> After some testing I have found that at my computer script which run from console is about 10 times more quick then browser based.
Welcome to shell.