Questions on updating statistics and index maintenance jobs

Since my question Index and statistics optimization scripts duration and log bloat problem. Looking for good strategy? has been closed because it was not focused enough I’ve three questions:

For statistics and index optimization I want to use Ola Hallengreens scripts.

  1. If I update statistics only or rebuild/reorganize indexes: Is there anyting dangerous by cancelling the job right in the middle of it if I see logfile becomes too big or the job takes too long and slows down daily work?

If not there is nothing I need to worry about and I can run it maybe on any evening or on a saturday and watch how it works and cancel it with no problem if some of the mentioned problems occur. Is this true?

  1. If I use Olas script configured like this (no offline index rebuild):
  • FragmentationLevel1 = 50%
  • FragmentationLevel2 = 80%
  • FragmentationHigh = ‘INDEX_REBUILD_ONLINE’
  • @UpdateStatistics nvarchar(max) = ‘ALL’,
  • @OnlyModifiedStatistics nvarchar(max) = ‘Y’,

Can I use this safely during worktime when people are working on the database?

  1. Is there any dangerous by doing such maintenance jobs (statistics update/index rebuild/index reorganize) which could damage the database if I use Ola with those parameters? The only thing I’ve seen where growing a large log file. Or can I install this with no worries and if anything occurs just cancel it (see question 1)?