Re: effective_cache_size

On 16/10/2018 17:38, Bruce Momjian wrote:
> diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
> index 2317e8b..e471d7f 100644
> --- a/src/backend/utils/misc/guc.c
> +++ b/src/backend/utils/misc/guc.c
> @@ -2987,10 +2987,9 @@ static struct config_int ConfigureNamesInt[] =
>
> {
> {"effective_cache_size", PGC_USERSET, QUERY_TUNING_COST,
> - gettext_noop("Sets the planner's assumption about the size of the disk cache."),
> - gettext_noop("That is, the portion of the kernel's disk cache that "
> - "will be used for PostgreSQL data files. This is measured in disk "
> - "pages, which are normally 8 kB each."),
> + gettext_noop("Sets the planner's assumption about the size of the data cache."),
> + gettext_noop("That is, the size of the cache used for PostgreSQL data files. "
> + "This is measured in disk pages, which are normally 8 kB each."),
> GUC_UNIT_BLOCKS,
> },
> &effective_cache_size,

This change completely loses the context that this is the kernel's/host
system's memory size. What is "data cache"? I think this is a bad
change. I know it's confusing, but the old description at least had
some basis in terms that are known to the user.

--
Peter Eisentraut http://www.2ndQuadrant.com/
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