Received: from malur.postgresql.org ([2a02:16a8:dc51::56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1g5Obs-0001Ym-Se for pgsql-hackers@arkaria.postgresql.org; Thu, 27 Sep 2018 05:13:09 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1g5Obq-0005KI-BU for pgsql-hackers@arkaria.postgresql.org; Thu, 27 Sep 2018 05:13:06 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1g5Obq-0005KB-0k for pgsql-hackers@lists.postgresql.org; Thu, 27 Sep 2018 05:13:06 +0000 Received: from mahout.postgresql.org ([2001:4800:1501:1::227]) by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1g5Obn-0005ni-1m for pgsql-hackers@lists.postgresql.org; Thu, 27 Sep 2018 05:13:04 +0000 Received: from coridan.postgresql.org ([2001:4800:1501:1::213]) by mahout.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1g5Obm-0002kQ-OW for pgsql-hackers@lists.postgresql.org; Thu, 27 Sep 2018 05:13:02 +0000 Received: from localhost ([127.0.0.1] helo=coridan.postgresql.org) by coridan.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1g5Obm-0000nY-2S for pgsql-hackers@lists.postgresql.org; Thu, 27 Sep 2018 05:13:02 +0000 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: Re: BUG #15307: Low numerical precision of (Co-) Variance To: pgsql-hackers@lists.postgresql.org From: Madeleine Thompson Cc: Dean Rasheed Date: Thu, 27 Sep 2018 05:12:23 +0000 User-Agent: pgcommitfest X-cfsender: madeleine In-Reply-To: References: <153313051300.1397.9594490737341194671@wrigleys.postgresql.org> Message-ID: <153802514313.25845.6696084477831363882.pgcf@coridan.postgresql.org> List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk VGhlIGZvbGxvd2luZyByZXZpZXcgaGFzIGJlZW4gcG9zdGVkIHRocm91Z2ggdGhlIGNvbW1pdGZl c3QgYXBwbGljYXRpb246Cm1ha2UgaW5zdGFsbGNoZWNrLXdvcmxkOiAgdGVzdGVkLCBwYXNzZWQK SW1wbGVtZW50cyBmZWF0dXJlOiAgICAgICB0ZXN0ZWQsIHBhc3NlZApTcGVjIGNvbXBsaWFudDog ICAgICAgICAgIG5vdCB0ZXN0ZWQKRG9jdW1lbnRhdGlvbjogICAgICAgICAgICBub3QgdGVzdGVk CgpUaGlzIGlzIG15IGZpcnN0IFBvc3RncmVTUUwgcmV2aWV3LiBIb3BlZnVsbHkgSSdtIGdldHRp bmcgaXQgcmlnaHQuIEkgaW5kZXBlbmRlbnRseSByYW4gaW50byB0aGUgYnVnIGluIHF1ZXN0aW9u IGFuZCBmb3VuZCB0aGF0IHRoZSBhdXRob3IgaGFkIGFscmVhZHkgd3JpdHRlbiBhIHBhdGNoLiBJ J20gaGFwcHkgdGhlIGF1dGhvciB3cm90ZSB0aGlzLg0KDQooMSkgSSBhbSBub3QgZXhwZXJpZW5j ZWQgd2l0aCBQb3N0Z3JlU1FMIGludGVybmFscywgc28gSSBjYW4ndCBjb21tZW50IG9uIHRoZSBj b2Rpbmcgc3R5bGUgb3IgdXNhZ2Ugb2YgaW50ZXJuYWwgZnVuY3Rpb25zLg0KICAgICAgICAgICAg ICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAg ICAgICAgICAgICAgDQooMikgVGhlIHBhdGNoIGFwcGxpZXMgY2xlYW5seSB0byBjZTQ4ODdiZDAy NWI5NWM3YjQ1NWZlZmQ4MTdhNDE4ODQ0YzZhYWQzLiAibWFrZSBjaGVjayIsICJtYWtlIGNoZWNr LXdvcmxkIiwgYW5kICJtYWtlIGluc3RhbGwiIHBhc3MuDQoNCigzKSBUaGUgcGF0Y2ggYWRkcmVz c2VzIHRoZSBudW1lcmljIGluYWNjdXJhY3kgcmVwb3J0ZWQgaW4gdGhlIGJ1Zy4gKFlheSEpIEkg YmVsaWV2ZSB0aGUgdGVzdHMgYXJlIHN1ZmZpY2llbnQgdG8gY29uZmlybSB0aGF0IGl0IHdvcmtz IGFzIGludGVuZGVkLiBJIGRvbid0IHRoaW5rIHRoZSB0ZXN0IGNvdmVyYWdlICpiZWZvcmUqIHRo aXMgcGF0Y2ggd2FzIHN1ZmZpY2llbnQsIGFuZCBJIGFwcHJlY2lhdGUgdGhlIGltcHJvdmVkIHRl c3QgY292ZXJhZ2Ugb2YgdGhlIGNvbWJpbmUgZnVuY3Rpb25zLiBJIHZlcmlmaWVkIHRoZSBuZXcg dGVzdHMgbWFudWFsbHkuDQoNCig0KSBUaGUgY29tbWVudHMgY2l0ZSBZb3VuZ3MgJiBDcmFtZXIg KDE5NzEpLiBUaGlzIGlzIGEgZGF0ZWQgY2l0YXRpb24uIEl0IGp1c3RpZmllcyBpdHMgYWxnb3Jp dGhtcyBiYXNlZCBvbiBwcmUtSUVFRTc1NCBzaW5nbGUtcHJlY2lzaW9uIGFyaXRobWV0aWMuICBN b3N0IG5vdGFibHksIGl0IGFzc3VtZXMgdGhhdCBmbG9hdGluZy1wb2ludCBkaXZpc2lvbiBpcyBu b3QgZXhhY3QuIFRoYXQgc2FpZCwgdGhlIGFsZ29yaXRobSBpcyBzdGlsbCBhIGdvb2QgY2hvaWNl OyBpdCBpcyBqdXN0aWZpZWQgbm93IGJlY2F1c2UgY29tcGFyZWQgdG8gdGhlIHN0YW5kYXJkIFdl bGZvcmQgdmFyaWFuY2UsIGl0IGlzIGxlc3MgcHJvbmUgdG8gY2F1c2luZyBwaXBlbGluZSBzdGFs bHMgb24gYSBtb2Rlcm4gQ1BVLiBNYXliZSBsaW5rIHRvIFNjaHViZXJ0ICYgR2VudHogMjAxOCAo aHR0cHM6Ly9kbC5hY20ub3JnL2NpdGF0aW9uLmNmbT9pZD0zMjIzMDM2KSBpbnN0ZWFkLiBUaGUg bmV3IGZsb2F0OF9jb21iaW5lIGNvbWJpbmUgY29kZSBpcyAoYWxtb3N0KSBTJkcgZXFuLiAyMjsg dGhlIGZsb2F0OF9hY2N1bSBjb2RlIGlzIFMmRyBlcW4uIDI4LiAgZmxvYXQ4X3JlZ3JfYWNjdW0g YW5kIGZsb2F0OF9yZWdyX2NvbWJpbmUgYXJlIFMmRyBlcW4uIDIyLg0KDQooNSkgSSB0aGluayB0 aGUgY29tbWVudCAvKiBXYXRjaCBvdXQgZm9yIHJvdW5kb2ZmIGVycm9yIHByb2R1Y2luZyBhIG5l Z2F0aXZlIHZhcmlhbmNlICovIGFuZCBhc3NvY2lhdGVkIGNoZWNrIGFyZSBvYnNvbGV0ZSBub3cu CgpUaGUgbmV3IHN0YXR1cyBvZiB0aGlzIHBhdGNoIGlzOiBXYWl0aW5nIG9uIEF1dGhvcgo=