DOC: 32-bit warning
xref #15889

cc @jorisvandenbossche  @TomAugspurger  # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24588?src=pr&el=h1) Report
> Merging [#24588](https://codecov.io/gh/pandas-dev/pandas/pull/24588?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/00391586e86f990804f5034c6f9894575080b4b0?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24588/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24588?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #24588   +/-   ##
=======================================
  Coverage   92.36%   92.36%           
=======================================
  Files         166      166           
  Lines       52497    52497           
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  Hits        48489    48489           
  Misses       4008     4008
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.79% <ø> (ø)` | :arrow_up: |
| #single | `43.04% <ø> (ø)` | :arrow_up: |


------

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> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24588?src=pr&el=footer). Last update [0039158...c4deb74](https://codecov.io/gh/pandas-dev/pandas/pull/24588?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24588?src=pr&el=h1) Report
> Merging [#24588](https://codecov.io/gh/pandas-dev/pandas/pull/24588?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/6249355b853878ff06ad8d2affe00d3b629a36ea?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24588/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24588?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #24588   +/-   ##
=======================================
  Coverage   92.38%   92.38%           
=======================================
  Files         166      166           
  Lines       52490    52490           
=======================================
  Hits        48493    48493           
  Misses       3997     3997
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.81% <ø> (ø)` | :arrow_up: |
| #single | `43.05% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24588?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24588?src=pr&el=footer). Last update [6249355...0fb5bc9](https://codecov.io/gh/pandas-dev/pandas/pull/24588?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 > Dropping 32-bit support, was this already discussed somewhere recently? (the linked issue seems to be mainly older comments)

I am just linking for posterity. > I am just linking for posterity.

I understand, but that means we decided to drop 32-bit support for 0.25.0 ? 
And my question was: is there a discussion somewhere about this decision? (I don't think I am opposed, but still good to have this decision recorded somewhere) that's the issue, this was long ago discussed. I see no reasont keep this burden (and actually the doc note is just to say we are going to do it). There was some discussion of finding out usage stats for 32bit python on windows.  Did anything come of that? For conda downloads, Linux and Mac 32-bit downloads are negligible
(Anaconda Distribution dropped Mac 32 and will drop 32-bit Linux this year).

For windows, the split is 94% to 6% for 64-bit to 32-bit.

On Thu, Jan 3, 2019 at 11:30 AM jbrockmendel <notifications@github.com>
wrote:

> There was some discussion of finding out usage stats for 32bit python on
> windows. Did anything come of that?
>
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 thanks @TomAugspurger yeah main motivation is that we don't have great testing, its just daily and hard to repro / fix.  We do test on 32-bit windows, right? So perhaps drop support for 32-bit
linux?

On Thu, Jan 3, 2019 at 12:48 PM Jeff Reback <notifications@github.com>
wrote:

> thanks @TomAugspurger <https://github.com/TomAugspurger> yeah main
> motivation is that we don't have great testing, its just daily and hard to
> repro / fix.
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 no we only test on 64-bit windows in fact we *only* here about 32-bit windows at release time I think (when wheels are built) any objections? @jreback can you raise this again in the original issue (#15889), and give people that participated there some time to respond?

(@TomAugspurger can you repeat those numbers there?) @jreback I already applied the part of this commit about the py27 warning to master and merged master in your branch. So now this is only about 32bit.