firebird-automations

Commented by: Dirk Rothe (drothe) Real World: We have a Field that ist mostly Null, but very selective if filled\. A lot of queries filter the records by applying the...

Commented by: @dyemanov Dirk, in this case a value distribution histogram is your friend, as with its existence the optimizer will not use an index for FIELD IS NULL while...

Commented by: Vladimir Arkhipov (arkinform) I see 2 applications of partial indexes: 1\. Restrict unique values for not null fields\. For example, number of case history for patient in medicine\....

Commented by: @dyemanov As for your case \(1\), I'm not sure I get it\. Firebird allows you to have any number of NULLs inside a uniquely constrained column\. What is...

Modified by: @dyemanov Component: Engine \[ 10000 \] Version: 3\.0 Alpha 1 \[ 10331 \] =\>

Commented by: Vladimir Arkhipov (arkinform) Unfortunately I did not know about this feature\. Thank you :\)

Commented by: Vladimir Arkhipov (arkinform) What about case \(2\) and speed of garbage collection? Does this affect garbage collection in principle?

Commented by: Dirk Rothe (drothe) Are "value distribution histograms" an expected 3\.0 feature? I haven't that found that much information by googling for it\.

Commented by: @dyemanov Vladimir: yes, these other points seem to be valid, although the cost of garbage collection in duplicated chains decreased since ODS11\. Dirk: yes, it is scheduled for...

Commented by: Dirk Rothe (drothe) Dmitry: Very nice, and a big thank you to all involved\!