Re: Statistics Import and Export
| От | Corey Huinker |
|---|---|
| Тема | Re: Statistics Import and Export |
| Дата | |
| Msg-id | CADkLM=cx-XM-PTscj+uDi24x3_vDpYMOjfHgw9CFt_ad5poc0A@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Statistics Import and Export (Tomas Vondra <tomas.vondra@enterprisedb.com>) |
| Ответы |
Re: Statistics Import and Export
|
| Список | pgsql-hackers |
Maybe I just don't understand, but I'm pretty sure ANALYZE does not
derive index stats from column stats. It actually builds them from the
row sample.
That is correct, my error.
> * now support extended statistics except for MCV, which is currently
> serialized as an difficult-to-decompose bytea field.
Doesn't pg_mcv_list_items() already do all the heavy work?
Thanks! I'll look into that.
The comment below in mcv.c made me think there was no easy way to get output.
The comment below in mcv.c made me think there was no easy way to get output.
/*
* pg_mcv_list_out - output routine for type pg_mcv_list.
*
* MCV lists are serialized into a bytea value, so we simply call byteaout()
* to serialize the value into text. But it'd be nice to serialize that into
* a meaningful representation (e.g. for inspection by people).
*
* XXX This should probably return something meaningful, similar to what
* pg_dependencies_out does. Not sure how to deal with the deduplicated
* values, though - do we want to expand that or not?
*/
* pg_mcv_list_out - output routine for type pg_mcv_list.
*
* MCV lists are serialized into a bytea value, so we simply call byteaout()
* to serialize the value into text. But it'd be nice to serialize that into
* a meaningful representation (e.g. for inspection by people).
*
* XXX This should probably return something meaningful, similar to what
* pg_dependencies_out does. Not sure how to deal with the deduplicated
* values, though - do we want to expand that or not?
*/
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