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help / color / mirror / Atom feedFrom: Tom Lane <[email protected]>
To: Jeff Davis <[email protected]>
Cc: Corey Huinker <[email protected]>
Cc: Andres Freund <[email protected]>
Cc: Michael Paquier <[email protected]>
Cc: jian he <[email protected]>
Cc: Nathan Bossart <[email protected]>
Cc: Bruce Momjian <[email protected]>
Cc: Matthias van de Meent <[email protected]>
Cc: Magnus Hagander <[email protected]>
Cc: Stephen Frost <[email protected]>
Cc: Ashutosh Bapat <[email protected]>
Cc: Peter Smith <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Cc: [email protected]
Subject: Re: Statistics Import and Export
Date: Mon, 24 Feb 2025 15:03:58 -0500
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
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<[email protected]>
Jeff Davis <[email protected]> writes:
> But you have a point in that float4in() does slightly more work than
> strtof() to handle platform differences about NaN/Inf. I'm not sure how
> much to weigh that concern, but I agree that there is non-zero
> cognitive overhead here.
If we're speaking strictly about the reltuples value, I'm not hugely
concerned about that. reltuples should never be NaN or Inf. There
is a nonzero chance that it will round off to a fractionally
different value if we pass it through strtof/sprintf on the pg_dump
side, but nobody is really going to care about that. (Maybe our
own pg_dump test script would, thanks to its not-too-bright dump
comparison logic. But that script is never going to see reltuples
values that are big enough to be inexact in a float4.)
I do buy the better-preserve-it-exactly argument for other sorts
of statistics, where we don't have such a good sense of what might
matter.
regards, tom lane
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Subject: Re: Statistics Import and Export
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