Le mar. 10 déc. 2019 à 20:48, Jeff Janes <jeff.ja...@gmail.com> a écrit :
> On Tue, Dec 10, 2019 at 11:43 AM Guillaume Lelarge <guilla...@lelarge.info> > wrote: > > This query uses the column statistics to estimate bloat. AFAIK, json >> columns don't have statistics, so the estimation can't be relied on (for >> this specific table at least). >> > > This was true prior to 9.5 (for xml at least, I don't know about json), > but should not be true from that release onward. But still the difference > between 74440704 and 74506240, this does seem to me to be straining at a > gnat to swallow a camel. > > I just checked, and you're right. There are less statistics with json, but the important ones (null_frac and avg_width) are available for json and jsonb datatypes. So the query should work even for tables using these datatypes. Thanks for the information, that's very interesting. And I apologize for the noise. -- Guillaume.
