Re: Statistics Import and Export - Mailing list pgsql-hackers

From Corey Huinker
Subject Re: Statistics Import and Export
Date
Msg-id CADkLM=cx-XM-PTscj+uDi24x3_vDpYMOjfHgw9CFt_ad5poc0A@mail.gmail.com
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In response to Re: Statistics Import and Export  (Tomas Vondra <tomas.vondra@enterprisedb.com>)
Responses Re: Statistics Import and Export
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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.

/*
 * 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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