Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1h5aXu-0005X1-3O for pgsql-hackers@arkaria.postgresql.org; Sun, 17 Mar 2019 18:30:06 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1h5aXs-0000dJ-5r for pgsql-hackers@arkaria.postgresql.org; Sun, 17 Mar 2019 18:30:04 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1h5aXr-0000dC-Ra for pgsql-hackers@lists.postgresql.org; Sun, 17 Mar 2019 18:30:03 +0000 Received: from meldrar.postgresql.org ([2a02:c0:301:0:ffff::31]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1h5aXk-0003IE-To for pgsql-hackers@postgresql.org; Sun, 17 Mar 2019 18:30:02 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=postgresql.org; s=20171124; h=Content-Type:In-Reply-To:MIME-Version:Date: Message-ID:From:References:Cc:To:Subject:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=irq5G5EInSVmHXwADWq4MLHCtO1BvKfWdd0yuK7IKS0=; b=pN4aoVYW43l9uD5WGCCHnfQV/H Ty8OwP94vOTUKobgCrG+CPxxZX//yy/g8najFo8f5KbQHgKK2V/DG9nrbME6MImzv2msXxDVS9Xvx mUzZFdE1PVnzGV8kXRwFLGpTyrb7+iGqTrg7Aohq6cFlOjjNKT/vilFdMop6AD915/Qa1KTO2HlVR e9dbaad7+vW48FDyFemYk1vJKvcVU2yhlrccpoC0o8zqxCPABYrxMwyxpva4E4nIJKgn/0upWSbsY 6DWiqXJh13XtyGrhMb4UOWSSfgkRGN/fSmUI7NOtuVAqvY1FiVUxUR4pa2UFk5mP5T0o4C6ylK/EE 9hNMDnEQ==; Received: from pool-96-250-83-19.nycmny.fios.verizon.net ([96.250.83.19] helo=Ph33r-Retina.home) by meldrar.postgresql.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1h5aXg-0008Ro-7g; Sun, 17 Mar 2019 18:29:54 +0000 Subject: Re: jsonpath To: Alexander Korotkov Cc: Pavel Stehule , Nikita Glukhov , Tomas Vondra , Andres Freund , Oleg Bartunov , Michael Paquier , Stas Kelvich , PostgreSQL-development , Thomas Munro , David Steele , Tom Lane , Andrew Dunstan , Robert Haas References: <67128b8b-2d80-9e51-20a8-9ac8e0e2243e@2ndquadrant.com> <220821fb-52c0-c277-0959-322c8eef76b2@postgrespro.ru> <04981bad-2156-a927-b04c-50ff2c9709ae@postgresql.org> <3247f0b1-ad4a-2d4e-e9b1-1eedc1e7e81a@postgresql.org> <4d103338-2f0b-d304-ee38-420c0fc973f8@postgresql.org> From: "Jonathan S. Katz" Openpgp: preference=signencrypt Autocrypt: addr=jkatz@postgresql.org; keydata= mQINBFtShwABEAC7PNHDUOTYuifpUCk23KqfxdQQkn4nkoxOXRK0+rAj36FiwqGB4TJFuOVZ sDFAEiSlC8Jt4y5Cs7B5tetT8JNd2cs6zp/udMJJDz9d65O9PDpdlMgAmIiTzpLlSdx8FG56 DTksaDv1d8j3cTJPSE4/fWSxqzA7o3Y9UuL7atZPrzfImgpRKs0of7elIHwOa8GucjyhYqcR h60wFBJc2KXqQdDYRTZy43DSnY/0VNc0omiH355fustvpm+m5HjD3w7qZyfN3fpKJpnX1LCF f3MnPHaDGITIYGRCBXvf0UqUtD6OEVWPv2C2gyqWMIpWmZTOgDufltKyIByKBoS9x0PlFkij 04X3KODCngt+N8Ssc9OICc6QSxhjoP48PYPdmiTmkrGuf0LX084wj1xeo1NX7XxZK39F6dTJ DhsIiW0sNS0xMxQHLHG9VLbPjx3SANQBh6BuryPz5ZupW9/TIDmkvprtU/oXfKgtfYm3fxmk EctxbWrEPsFTFPyuMqQu6l+xyQv0s1VLZfjNWaua6H1/gGoIt6kRnn5qMXDVVpijuWkHbv7G ngaQMd258UrrOEHnnjzhQ7jxMWV9D+emxbAtlIxnYvCWlV4IwAQhEHfvudqYaIY3hNWrvQ6H GB2KXoTZYN9g5djm14/5nj1IU5zOcovkjJnKhoo9iStnpFF2cwARAQABtCdKb25hdGhhbiBT LiBLYXR6IDxqa2F0ekBwb3N0Z3Jlc3FsLm9yZz6JAlQEEwEIAD4CGwMFCQeGH4AFCwkIBwIG FQoJCAsCBBYCAwECHgECF4AWIQT6hLaVryv3miBkP/HxBJxynxxlJwUCW1KJJQAKCRDxBJxy nxxlJwjrD/kBgqsW4QpNpTFw7ifRokZV08CCX4huPBJQ91rrv+UEWlEcotFBHVkYyHnpzARl tcZxhJ9CbFxjniH9cOTty5T/O1yolbOHtZSW8Z8aWV6BVEbjMb+BFxSSLm7RnvJdzQbGCZq2 ZZvfVpB6z3EHYph4KDdVKvMFjoLskxmdS1DE0tE3zTxvoQsi24Q+HOS07kUjs6fsu/WICMfz mgO++AWG9Y0CvN0mm4TkujESzyKM9E5irD+leEMIcddl51Aa2c/VMfBXQbRmpHIgUFTmuHQD CnQih+9i3OJAksDg66SP8a7yiXv5mwvyDi1EfTGVKYR2j+pwyjwnC3oIbvDMmB3uTn2JIjnT iZKPVtAcAylXjubFltihQgNyuShdP4W+kBwZizhUFqUVL8Anx+KoytYmJPfMRFLGuK4obXKq a2ZS3k9KB+H+isOx2nFJOsc7V360Zp1DVaNmuiK10TT6QndShSPaqkJqFtCb6r92rZ9sZM/L 3vtCI4Rrl3Pt1MgtENXupS8gZpJnAYS0j5A1PAZ09r6ANoaeMHspF+5J5fOHeEvqphXr36mm a83Vl1t4orPb0+QmmijmlpseDU63M88Aw5p3c4qj7t8Qr2EZ5zrn7/sFn5wOfbs8Nymxafif QCnlV2vg9p0m7vSk/yLJ4PFZvs52FgqAGRCdRn0s2EC99bkCDQRbUocAARAAv8ho/toQ9DG3 j4f9h9n1aRHr2FlviN2Utpy6L8+dfDggO0geilmkGQOolZ2E60gGfye/kUtF9W3NByO4hxDR 9u6qbOXcdqnuA+cc68EfqlWFJrVtYFxt0h4ElWYOYnIezKthriWch/FY70FGrxs3z8UHOHq5 0wBW433eTvZm90WixBiXEt2v1DgW4Vr3ymfO7Aap/IYyPuE4JzgudAuAl0HKPyNEHWHG1dAb jX1RiCw9gknIDWQOF0B4UAaJctWGVcnZ3A2ULwNGMa1P9ZJlBWf1vcj01aiHMU0yQ7JjJiSp vfm9eM0uSLwRdDrJjyl5ZZqVumjdv2SMNQ8GvYRbEMys3GGDSt9zXgfCSUnPnJfYxjzBHRI6 x44Wfsx8S6hWxepOogCJJ/g67Bk9mY8YV4klWIXDJVOL5jnBC09DbsZG81JaE2QxB8Y7W36Z Mroi9XMxg3s805hQAQUvdG/poU8hN8BWdrnTm/+4eQQp7gDY1ePDmGM6bJC+OHOSnFtR/f+7 0zpKJ10cc7cBygGnl1yR3KjhFyAWUFvP4ZGziKCcpMwXZfe9PGuyA/YOubMphxIn3YsK2wrd faKZYX2GMZCZhMMcvx9IpQrxIJgU+VlwXu/O+Lk10VIPcxPJJwmpdI6HzcS8ZgG6IMcC444X XTuLaP8j2mgcMvYak3ScCykAEQEAAYkCPAQYAQgAJhYhBPqEtpWvK/eaIGQ/8fEEnHKfHGUn BQJbUocAAhsMBQkHhh+AAAoJEPEEnHKfHGUnReMP/RA2UhGQj+G4uBshkRLjpRysabdPqgQB dEBk6wYbio88Wg/2/hgY7UzmDDEwX3sZfQDcrI6+vIobI8uqstZID+WgAAa1JLfChMyVQnSy 0zfWMOABXscc5tGuvFRZvJklTissMFjXUwaREEKp4ZikTvJ/62MCjSdtrUhnPLvoTsHTKRKD ichE+b5A54alwsubTijw12O6N22r5IjZiiSZV0u7dsShyKw+7wCSax9fuBoE43NMYf+dnjMK nerAQYUcZWYMnk+EC8RaqYAxv6XZ2tKx1AkGGktwkQIBwrz9IlDSvJ3LWJ2UIIuLRTdngNgg GIL4zzuUa2F56FqskQIuYMaNETk6LYfalBDQ6TVLAcgCPQxp4k4i/PRsZ3lZ2ZhRHRYciOvm kp+I6EfHwllQpYrWs1thluBGqlJSVJgKl0IOFvKLsQ6KKfqzAwh6FxrO5qajp4viNIgtWoFw O5Bp0jgFTbH2OrMWIRfUdUCH1Djbuo65svhNj7FNsQVYzHDI+Nd1I/LOBoPc3UorRMF2M4JV kUR7skOHWUbPTSNUr7qc14NSMY3PKjGeVGAsBVHBPvmRx/Ss2tW/TpJWpxg4pmquFQSXuaYh Yf4FN8Sxy320pcr+FqN8AhZkYJcNY82OTtR5VEKRC/mYcyq61qXIKqngydn79bJjGxHipxyF FmEC Message-ID: <36067d03-c085-b3ef-f379-a00aa4bff7e5@postgresql.org> Date: Sun, 17 Mar 2019 14:29:44 -0400 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:60.0) Gecko/20100101 Thunderbird/60.5.3 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="1mK84aqkZF8B8Z71pF1Lrt4EF6DQ9CUh5" List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --1mK84aqkZF8B8Z71pF1Lrt4EF6DQ9CUh5 Content-Type: multipart/mixed; boundary="iWn2jIXWE0YuibSSKeHGiL8cQ5WSg3PRa"; protected-headers="v1" From: "Jonathan S. Katz" To: Alexander Korotkov Cc: Pavel Stehule , Nikita Glukhov , Tomas Vondra , Andres Freund , Oleg Bartunov , Michael Paquier , Stas Kelvich , PostgreSQL-development , Thomas Munro , David Steele , Tom Lane , Andrew Dunstan , Robert Haas Message-ID: <36067d03-c085-b3ef-f379-a00aa4bff7e5@postgresql.org> Subject: Re: jsonpath References: <67128b8b-2d80-9e51-20a8-9ac8e0e2243e@2ndquadrant.com> <220821fb-52c0-c277-0959-322c8eef76b2@postgrespro.ru> <04981bad-2156-a927-b04c-50ff2c9709ae@postgresql.org> <3247f0b1-ad4a-2d4e-e9b1-1eedc1e7e81a@postgresql.org> <4d103338-2f0b-d304-ee38-420c0fc973f8@postgresql.org> In-Reply-To: --iWn2jIXWE0YuibSSKeHGiL8cQ5WSg3PRa Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 3/17/19 1:14 PM, Alexander Korotkov wrote: > On Sun, Mar 17, 2019 at 8:06 PM Jonathan S. Katz = wrote: >> On 3/17/19 1:02 PM, Alexander Korotkov wrote: >>> >>> Thank you for the explanation. Is it jsonb_ops or jsonb_path_ops? >> >> I just used "USING gin(col)" so jsonb_ops. >=20 > I see. So, jsonb_ops extracts from this query only existence of > .length key. And I can bet it exists in all (or almost all) the > documents. Thus, optimizer thinks index might be useful, while it's > useless. There is not much can be done while we don't have statistics > for jsonb (and access to it from GIN extract_query). So, for now we > can just refuse from extracting only keys from jsonpath in jsonb_ops. > But I think it would be better to just document this issue. In future > we should improve that with statistics. That seems to make sense, especially given how I've typically stored JSON documents in PostgreSQL. It sounds like this particular problem would be solved appropriately with JSONB statistics. Thanks, Jonathan --iWn2jIXWE0YuibSSKeHGiL8cQ5WSg3PRa-- --1mK84aqkZF8B8Z71pF1Lrt4EF6DQ9CUh5 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE+oS2la8r95ogZD/x8QSccp8cZScFAlyOkhkACgkQ8QSccp8c ZSeB1g//SEQBvdltn+ux9M3kqD5yAfuUEdi9Dto48S7kwwp1rRhhcdS5Mf0xNs5F eoRUPbJWgvIAF4zFzlHDeSIyAQVHUOp05ng0w9CElp6T8OE7TFhz6exDlkx/wOeM 80R9/0f+79BRY7TlIi7cdJal69ut2hhZak4v5ufGxB63KqXI5u+/UvBvFEZ3todF GNahacIU/V2hNWxpE4E7JGTHI0oJGzouKB+KkAsEEEOCrv8MTl1UordjMQ8ZXCX6 M7EUyxMwE6qgpC/9FAp+g7sj5TGQ+PeoqAREHMe0fSj+0Pa3WJ4SrSwD9vBircNQ TWnaTnOXVL41KVuvA9yHUJaxCaX4QoGOJkLP9BheyWZhYbnWURYosNFo/nZfIJei +vDMYsUzFRDsQlY1zFyhkyz4AK/m2ozNR3sWwF4Vix9w2DUiXfmxBHXsC+AMMaOp 4W65MX2JnmXLUh74x+MdWQ6w6AvAkd+dn2Uzb4Y0l8dpK5mWirkLWuArckZiQOEv AO35VwhL8ELGj2SHuATil5yDAq9N+dnkemP6BbZIcY9W2BMGuAnprFXmbjNBv/mM bhkGt5NYhEgEe8j8r5Vh/vjlqfSL4jxBYW1BK44r/IDqaRNUgwQzTn0zE3yRjK/W L/gbh1qMtVqWYiLWu0kQuGu2Xn6m/qlkmR2v/pu8Fpt3zUAvq68= =ZsG8 -----END PGP SIGNATURE----- --1mK84aqkZF8B8Z71pF1Lrt4EF6DQ9CUh5--