Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jg77H-0001pg-Oa for pgsql-hackers@arkaria.postgresql.org; Tue, 02 Jun 2020 13:38:07 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1jg77G-00004y-G8 for pgsql-hackers@arkaria.postgresql.org; Tue, 02 Jun 2020 13:38:06 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from <9erthalion6@gmail.com>) id 1jg77G-00004r-8t for pgsql-hackers@lists.postgresql.org; Tue, 02 Jun 2020 13:38:06 +0000 Received: from mail-wr1-x442.google.com ([2a00:1450:4864:20::442]) by magus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from <9erthalion6@gmail.com>) id 1jg77C-0004dm-WF for pgsql-hackers@postgresql.org; Tue, 02 Jun 2020 13:38:05 +0000 Received: by mail-wr1-x442.google.com with SMTP id c3so3413889wru.12 for ; Tue, 02 Jun 2020 06:38:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=T9ZFjQHI93O1rJC7TnaCDcgcmZ8mfeIALEaWk1pzQsE=; b=IaR8RWMuU4bH1FHcLDz3hZnFqT+Mou+jPy+ELmbjl9rIpe2H54EbraNjVieNTsK4Tv L2badO2OdsmYhgQXVfvVpKRQWQg41RCOR8yuyphHxHrxsCc00nuF/5SfExEYI54n2fS/ gltvjjOoYYLhoh872HbB+eqbdSrqLxPF6KIRlK399jGKvLfIEhuXfFuW/W3YkBrP8nIr 9n1+sdTsN1I2WRzlmGFxmEDKdm0IRkdrO0vkQOhZoDahVM4Da9Mrj/F42H6zLrMwuV41 eq9zNGhh4ItcW5D6wRWQq/rnQhdLSK7yuGax/tia1bsx5zhZu+2tFugoVpZpTuK8k9qX QNrQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=T9ZFjQHI93O1rJC7TnaCDcgcmZ8mfeIALEaWk1pzQsE=; b=SPKqfiFDRPMCuThADQ45QS6m/2qR0QifACtRRRuJ20xPLobw630dP3qeEL/cSKqwxz 6vwvWvrEqyQ2lwgn4E+7hiUvxEM9MpKxzPxLXWBBg+9lQwgYK2EUHRkDCQOu0/bbYFDW s4d5KkmgmLnmwv31/B0vK7coFYfmjZLoXBwLNsaMh5634g6gDobiLcxKcMDjDXuUtu22 5Nq6B9k9sqijajBu+gQbF3GqCU8H9sPICzSWIqeCUbHc4C7Pcsg5WFg5pqLWzr3WPr90 TF/Z9bNghlkrjqINwBxov7fqePFGpoN2JgSQBopm1/7uYNTMBZL9VD2uddRGb1bO2fzD Rxrw== X-Gm-Message-State: AOAM530IygSKtJKGkINQAT67J2iTD5khRkcVUoNmc2SATvHbLGKL09bt aZVe0/9LiKtQkornBpZgrQM= X-Google-Smtp-Source: ABdhPJyDpWV+BMUl4+pStU0ML4E+jje17EeSWHrR5kI96NWVWi1N1fMTxlM34PT7rPZgWiFTp95I3w== X-Received: by 2002:adf:ea8b:: with SMTP id s11mr26985070wrm.168.1591105080374; Tue, 02 Jun 2020 06:38:00 -0700 (PDT) Received: from localhost (dslb-188-102-096-018.188.102.pools.vodafone-ip.de. [188.102.96.18]) by smtp.gmail.com with ESMTPSA id y66sm3608641wmy.24.2020.06.02.06.37.58 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 02 Jun 2020 06:37:59 -0700 (PDT) Date: Tue, 2 Jun 2020 15:40:06 +0200 From: Dmitry Dolgov <9erthalion6@gmail.com> To: Andy Fan Cc: Floris Van Nee , Dilip Kumar , David Rowley , Kyotaro Horiguchi , Tomas Vondra , Peter Geoghegan , Jesper Pedersen , Alvaro Herrera , Thomas Munro , James Coleman , Rafia Sabih , Jeff Janes , "bhushan.uparkar@gmail.com" , PostgreSQL-development , Alexander Korotkov Subject: Re: Index Skip Scan Message-ID: <20200602132124.v6orhdvxjecbkmkh@localhost> References: <20200325085100.5fixaiteuoln4f45@localhost> <20200405161029.fpqqll7xbgfqy5na@localhost> <80ef5f0744f542b18e508fb589a6425a@opammb0562.comp.optiver.com> <20200406163941.rh3okji2rhbnptyt@localhost> <8abe43ac82714c2f9044fb8bac0ebfd0@opammb0562.comp.optiver.com> <20200407194220.edf4nbi7l4cpxk4v@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk > On Tue, Jun 02, 2020 at 08:36:31PM +0800, Andy Fan wrote: > > > Other than that to summarize current open points for future readers > > (this thread somehow became quite big): > > > > * Making UniqueKeys usage more generic to allow using skip scan for more > > use cases (hopefully it was covered by the v33, but I still need a > > confirmation from David, like blinking twice or something). > > > > * Suspicious performance difference between different type of workload, > > mentioned by Tomas (unfortunately I had no chance yet to investigate). > > > > * Thinking about supporting conditions, that are not covered by the index, > > to make skipping more flexible (one of the potential next steps in the > > future, as suggested by Floris). > > > > Looks this is the latest patch, which commit it is based on? Thanks I have a rebased version, if you're about it. Didn't posted it yet mostly since I'm in the middle of adapting it to the UniqueKeys from other thread. Would it be ok for you to wait a bit until I'll post finished version?