Hi Folks, thanks for reading my questions
Ive been researching about doing update statistics on ASE 15.0.3 , and some things i cant find a clear docmentation referece...
1) When doing a reorg rebuild, event that the indexes are effectively rebuilt, the statistics for all columns in the indexes are not collected along it.
Only for the leading column for the PK. So, its necessary to rerun update index statistics, in order to gather the statistics for the remaining columns in the indexes. Is this correct? If its necessary to collect the indexes, it would be realy helpful to DBAs to have this information on the following link
2) Our standard procedure is to run “update index statistics table“ for all of our tables. We are planning to use sampling , but it seems necessary to collect
a full table statistics for the given table in order to have sampling working as expected. Is it correct? (we are using DOL tables). Could be possible to run update statistics on the PK first in order to have ASE to start using sampling properly?
3) Its not clear to me if using “sampling” effectively makes update statistics to collect a lower number of pages. Im in doubt if ASE effectively reads all the pages
but discard information, or if it somehow uses the OAM in order to skip reading pages… Is there a good reference for this?