| From: | Alexander Korotkov <aekorotkov(at)gmail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Noah Misch <noah(at)leadboat(dot)com>, Nathan Boley <npboley(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Collect frequency statistics for arrays |
| Date: | 2012-03-04 13:31:57 |
| Message-ID: | CAPpHfdtPPkVS-rKc7=9FU3drDm3LquvTJF8WkDXcCxxqWKciow@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Sun, Mar 4, 2012 at 5:38 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> 1. I'm still unhappy about the loop that fills the count histogram,
> as I noted earlier today. It at least needs a decent comment and some
> overflow protection, and I'm not entirely convinced that it doesn't have
> more bugs than the overflow issue.
>
Attached patch is focused on fixing this. The "frac" variable overflow is
evaded by making it int64. I hope comments is clarifying something. In
general this loop copies behaviour of histogram constructing loop of
compute_scalar_stats function. But instead of values array we've array of
unique DEC and it's frequency.
------
With best regards,
Alexander Korotkov.
| Attachment | Content-Type | Size |
|---|---|---|
| histogram_fix.patch | text/x-patch | 2.8 KB |
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