Hi Mich, The statistic is stored in SYSTEM.STATS table. And yes, there are guideposts per column family. As for (3) and (4) I think the answer is no. Guideposts are more like a point for specific row key (so if we scan for specific row key we can find quickly whether to start scanning) and let us run more scans in parallel. And they are using on client side.
Thanks, Sergey On Sun, Oct 30, 2016 at 3:55 PM, Mich Talebzadeh <mich.talebza...@gmail.com> wrote: > According to document <https://phoenix.apache.org/update_statistics.html> > > The UPDATE STATISTICS command updates the statistics collected on a table, > to improve query performance. This command collects a set of keys per > region per column family that are equal byte distanced from each other. > These collected keys are called *guideposts* and they act as > *hints/guides* to improve the parallelization of queries on a given > target region. > > Few questions I Have > > > 1. Where are the statistics for a given table is kept > 2. Does this mean that each column family of a table has its own > statistics > 3. Is statistics collected similar to statistics for store-index in > Hive ORC table > 4. Can statistics been used in predicate push down > > > Thanks > > Dr Mich Talebzadeh > > > > LinkedIn * > https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABUrV8Pw > <https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABUrV8Pw>* > > > > http://talebzadehmich.wordpress.com > > > *Disclaimer:* Use it at your own risk. Any and all responsibility for any > loss, damage or destruction of data or any other property which may arise > from relying on this email's technical content is explicitly disclaimed. > The author will in no case be liable for any monetary damages arising from > such loss, damage or destruction. > > >
