Re: Prefix operator for text and spgist support

On Thu, Mar 22, 2018 at 7:09 PM, Teodor Sigaev <teodor(at)sigaev(dot)ru> wrote:

> Patch looks resonable, but I see some place to improvement:
> spg_text_leaf_consistent() only needs to check with text_startswith() if
> reconstucted value came to leaf consistent is shorter than given prefix.
> For example, if level >= length of prefix then we guarantee that fully
> reconstracted is matched too. But do not miss that you may need to return
> value for index only scan, consult returnData field
>
> In attachment rebased and minorly edited version of your patch.

I took a look at this patch. In addition to Teodor's comments I can note
following.

* This line looks strange for me.

- if (strategy > 10)
+ if (strategy > 10 && strategy != RTPrefixStrategyNumber)

It's not because we added strategy != RTPrefixStrategyNumber condition
there.
It's because we already used magic number here and now have a mix of magic
number and macro constant in one line. Once we anyway touch this place,
could we get rid of magic numbers here?

* I'm a little concern about operator name. We're going to choose @^
operator for
prefix search without any preliminary discussion. However, personally I
don't
have better ideas :)

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company