Re: [BUGS] BUG #14155: bloom index error with unlogged table

On Tue, Jun 7, 2016 at 1:35 AM, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>
wrote:

> On Fri, Jun 3, 2016 at 11:25 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > Michael Paquier <michael(dot)paquier(at)gmail(dot)com> writes:
> >> Actually, the docs could be more polished.
> >
> > I think the docs could stand to be rewritten from scratch ;-). But
> > upthread there was an offer to work on them if we made the code behavior
> > saner. I've done the latter part, I don't want to do the former.
>
> I have finally given a shot at improving the docs with the attached.
> Comments are welcome.
>

​Looks good. Thanks!​

​Some minor word-smithing​ related stuff and one definitional concern:

​"of all indexed attributes and so it can report false positives" -> of all
indexed attributes and as such is prone to reporting false positives;

​"in the set, however" -> "in the set although"
​
​"one only needs a single bloom index (default 80, maximum 4096)" -> ​the
default seems like it would be better placed in the first paragraph of the
intro where "whose size in calculated in bits" is mentioned; or better yet
dropped altogether since the parameters section covers the defaults.

*** "to the number of the column for" - the examples imply that each
parameter refers to columns by name, not number.

"a bloom index representing first the advantage to be more" - this intro
to the example needs some work. maybe: "Here is a more complete example of
index definition and usage, as well as a comparison with the equivalent
btree index. The bloom index is considerably smaller as well as performs
better than the btree index.

---As an aside, is a multi-column index really a fair comparison here?

---Leaving a sequential scan explain analyze in place should be considered.

​"The Bloom opclass interface" -> The Bloom opclass interface requires a
hash function for the indexing datatype and an equality operator for
searching. The example...(drop the simple conclusion the word the equality
operator part better).

​"are implemented with the module" - are supplied by this module. (side
question, for 10.0 how about we call these extensions instead of modules?)

David J.