Re: auto-sizing wal_buffers

Fujii Masao wrote:
> +/* Minimum setting used for a lower bound on wal_buffers */
> +#define XLOG_BUFFER_MIN 4
>
> Why didn't you use XLOG_BUFFER_MIN instead of XLOGbuffersMin?
> XLOG_BUFFER_MIN is not used anywhere for now.
>

That's a typo; will fix.

> + if (XLOGbuffers < (XLOGbuffersMin * 2))
> + XLOGbuffers = XLOGbuffersMin * 2;
> + }
>
> Why is the minimum value 64kB only when wal_buffers is set to
> -1? This seems confusing for users.
>

That's because the current default on older versions is 64kB. Since the
automatic selection is going to be the new default, I hope, I don't want
it to be possible it will pick a number smaller than the default of
older versions. So the automatic lower limit is 64kB, while the actual
manually set lower limit remains 32kB, as before.

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Greg Smith 2ndQuadrant US greg(at)2ndQuadrant(dot)com Baltimore, MD
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