Re: Memory unit GUC range checks - Mailing list pgsql-hackers

From Alexander Korotkov
Subject Re: Memory unit GUC range checks
Date
Msg-id CAPpHfdvLQCw2OiR4nHk+tP9OBS3aoB-_eP8qZetG9eZVLOVtog@mail.gmail.com
Whole thread Raw
In response to Re: Memory unit GUC range checks  (Andres Freund <andres@anarazel.de>)
Responses Re: Memory unit GUC range checks  (Heikki Linnakangas <hlinnaka@iki.fi>)
List pgsql-hackers
On Wed, May 16, 2018 at 10:41 PM, Andres Freund <andres@anarazel.de> wrote:
On 2018-05-16 15:49:29 +0300, Heikki Linnakangas wrote:
> Here's a pretty straightforward fix for these two issues. Any objections or
> better ideas?

Generally ok, two minor points:

> diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
> index 7cd2d2d80e..93402030f7 100644
>       {"TB", GUC_UNIT_BLOCKS, (1024 * 1024 * 1024) / (BLCKSZ / 1024)},
>       {"GB", GUC_UNIT_BLOCKS, (1024 * 1024) / (BLCKSZ / 1024)},
>       {"MB", GUC_UNIT_BLOCKS, 1024 / (BLCKSZ / 1024)},
>       {"kB", GUC_UNIT_BLOCKS, -(BLCKSZ / 1024)},
> +     {"B", GUC_UNIT_BLOCKS, -(BLCKSZ / (1024 * 1024))},

Isn't this 0 in the common case of 8k pages?


>       {"TB", GUC_UNIT_XBLOCKS, (1024 * 1024 * 1024) / (XLOG_BLCKSZ / 1024)},
>       {"GB", GUC_UNIT_XBLOCKS, (1024 * 1024) / (XLOG_BLCKSZ / 1024)},
>       {"MB", GUC_UNIT_XBLOCKS, 1024 / (XLOG_BLCKSZ / 1024)},
>       {"kB", GUC_UNIT_XBLOCKS, -(XLOG_BLCKSZ / 1024)},
> +     {"B", GUC_UNIT_XBLOCKS, -(XLOG_BLCKSZ / (1024 * 1024))},

Same?

As I understand, in these cases multiplier should be just -BLCKSZ and -XLOG_BLCKSZ correspondingly.

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

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