| From: | Merlin Moncure <mmoncure(at)gmail(dot)com> |
|---|---|
| To: | Josh Berkus <josh(at)agliodbs(dot)com> |
| Cc: | postgres performance list <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: working around JSONB's lack of stats? |
| Date: | 2015-02-02 15:42:48 |
| Message-ID: | CAHyXU0xpr5C+x1RmRzo9ppGZnVYq_8d2htojHisE-KHSj2YdOA@mail.gmail.com |
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| Lists: | pgsql-performance |
On Tue, Jan 27, 2015 at 1:06 AM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
> Folks,
>
> Currently, JSONB fields don't have statistics, and estimate a flat 1%
> selectivity. This can result in poor query plans, and I'm wondering if
> anyone has a suggested workaround for this short of hacking a new
> selectivity function. For example, take the common case of using JSONB
> to hold a list of "tags" for tagging documents:
hm, Why stop at jsonb? What's needed is a way to override the
planner's row estimate in a general way.
merlin
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