Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1weoCM-00522H-1J for pgsql-committers@arkaria.postgresql.org; Wed, 01 Jul 2026 06:13:26 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.96) (envelope-from ) id 1weoCJ-00BtSL-3A for pgsql-committers@arkaria.postgresql.org; Wed, 01 Jul 2026 06:13:23 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1weoCJ-00BtSD-2R for pgsql-committers@lists.postgresql.org; Wed, 01 Jul 2026 06:13:23 +0000 Received: from mahout.postgresql.org ([2001:4800:3e1:1::227]) by makus.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1weoCI-000000012Bh-0DY0 for pgsql-committers@lists.postgresql.org; Wed, 01 Jul 2026 06:13:22 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=postgresql.org; s=20171124; h=Date:Message-Id:Subject:To:From:MIME-Version: Content-Type:Sender:Reply-To:Cc:Content-Transfer-Encoding:Content-ID: Content-Description:In-Reply-To:References; bh=3Jv98aV/z64xc78u1WvNGbjmYYXDuuXGEeGLJ5lonhE=; b=jwNCOrzDthmFGjTz0fHdll5uXY 9Uzez/tGWsLaKR9ntR3SrSC2DoRqRHfyNuUhj6tBnyrQYwaQ6uYEGTPes0KdJNJOfLCPrt8HVkXDY 2DqZx+jsNFYf+NYOXXex3zfASOePtKkosq7wrSm9owpVSRSkN992YW1kGQ7VMuMhnUcUP28XtPdcd ksS1p/2Vsxrzvh6g1E7G9bpBescc7r5PaCy12VJFyQQaNtU8KxaKrAtd9/qrBizflfSFsb0Zw9HkY nrSFB+qbSm9XqPp2kQr1VENLaoLMj5HbVJSJRg/mKsd0aTHkIL5Qzq3fLKft+CCJgEahy1wuNHsbn AgK0dyDA==; Received: from gemulon.postgresql.org ([2001:4800:3e1:1::198]) by mahout.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1weoCH-0095d5-2V for pgsql-committers@lists.postgresql.org; Wed, 01 Jul 2026 06:13:21 +0000 Received: from localhost ([127.0.0.1] helo=gemulon.postgresql.org) by gemulon.postgresql.org with esmtp (Exim 4.96) (envelope-from ) id 1weoCH-000sLJ-2l for pgsql-committers@lists.postgresql.org; Wed, 01 Jul 2026 06:13:21 +0000 Content-Type: multipart/mixed; boundary="===============6319620624911300359==" MIME-Version: 1.0 From: Richard Guo To: pgsql-committers@lists.postgresql.org Subject: pgsql: Improve UNION's output row count estimate X-Auto-Response-Suppress: All Auto-Submitted: auto-generated Message-Id: Date: Wed, 01 Jul 2026 06:13:21 +0000 List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk --===============6319620624911300359== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 SW1wcm92ZSBVTklPTidzIG91dHB1dCByb3cgY291bnQgZXN0aW1hdGUKCkEgVU5JT04gKG5vdCBV TklPTiBBTEwpIHJlbW92ZXMgZHVwbGljYXRlcywgc28gaXRzIG91dHB1dCBoYXMgbm8gbW9yZQpy b3dzIHRoYW4gaXRzIGlucHV0LiAgVGhlIHBsYW5uZXIgZGlkIG5vdCBhY2NvdW50IGZvciB0aGlz OiBpdCBzZXQgdGhlCnNldC1vcCByZWxhdGlvbidzIHJvdyBjb3VudCB0byB0aGUgdG90YWwgc2l6 ZSBvZiB0aGUgYXBwZW5kZWQgaW5wdXQsCmFzIHRob3VnaCBkZWR1cCByZW1vdmVkIG5vdGhpbmcu ICBUaGF0IGluZmxhdGVkIGVzdGltYXRlIHRoZW4KcHJvcGFnYXRlZCB0byBldmVyeSBub2RlIGFi b3ZlIHRoZSBVTklPTiwgbGVhZGluZyB0byBwb29yIHBsYW4gY2hvaWNlcwpzdWNoIGFzIGEgaGFz aCBqb2luIHdpdGggYSBmdWxsIHRhYmxlIHNjYW4gd2hlcmUgYW4gaW5kZXggbmVzdGVkIGxvb3AK d291bGQgaGF2ZSBiZWVuIGNoZWFwZXIuCgpUaGlzIHBhdGNoIGVzdGltYXRlcyB0aGUgbnVtYmVy IG9mIGRpc3RpbmN0IG91dHB1dCByb3dzIGFzIHRoZSBzdW0gb2YKdGhlIHBlci1jaGlsZCBkaXN0 aW5jdC1ncm91cCBlc3RpbWF0ZXMgaW5zdGVhZC4gIFRoaXMgcmVsaWVzIG9uIHRoZQpmYWN0IHRo YXQ6CgogIGRpc3RpbmN0KEEgdW5pb24gQikgPD0gZGlzdGluY3QoQSkgKyBkaXN0aW5jdChCKQoK dGhhdCBpcywgdGhlIHVuaW9uIGNhbm5vdCBoYXZlIG1vcmUgZGlzdGluY3Qgcm93cyB0aGFuIGl0 cyBjaGlsZHJlbiBkbwppbiB0b3RhbC4gIEFuZCBiZWNhdXNlIGVhY2ggY2hpbGQncyBkaXN0aW5j dC1ncm91cCBlc3RpbWF0ZSBuZXZlcgpleGNlZWRzIHRoYXQgY2hpbGQncyByb3ctY291bnQgZXN0 aW1hdGUsIHRoaXMgc3VtIGlzIG5ldmVyIGxhcmdlciB0aGFuCnRoZSBvbGQgZXN0aW1hdGUsIHNv IGl0IG9ubHkgdGlnaHRlbnMgdGhlIHByZXZpb3VzIG92ZXItZXN0aW1hdGUuCgpBdXRob3I6IFJp Y2hhcmQgR3VvIDxndW9mZW5nbGludXhAZ21haWwuY29tPgpSZXZpZXdlZC1ieTogRGF2aWQgUm93 bGV5IDxkZ3Jvd2xleW1sQGdtYWlsLmNvbT4KUmV2aWV3ZWQtYnk6IENoZW5ncGVuZyBZYW4gPGNo ZW5ncGVuZ195YW5Ab3V0bG9vay5jb20+CkRpc2N1c3Npb246IGh0dHBzOi8vcG9zdGdyLmVzL20v Q0FNYldzNDhGdTFuaEdYUGE2MG9jK2FkajdnZTRkbjBuSGhxbmdxS3ZPVlZRUDYxZHVBQG1haWwu Z21haWwuY29tCgpCcmFuY2gKLS0tLS0tCm1hc3RlcgoKRGV0YWlscwotLS0tLS0tCmh0dHBzOi8v Z2l0LnBvc3RncmVzcWwub3JnL3BnL2NvbW1pdGRpZmYvYmU2OWE1ZmYxZmQ5NmNkYmZlOTE3YWM0 NzM5MTQyZTUyYWFiMTI2ZQoKTW9kaWZpZWQgRmlsZXMKLS0tLS0tLS0tLS0tLS0Kc3JjL2JhY2tl bmQvb3B0aW1pemVyL3ByZXAvcHJlcHVuaW9uLmMgfCA2OCArKysrKysrKysrKysrKystLS0tLS0t LS0tLS0tLS0tLS0tCnNyYy90ZXN0L3JlZ3Jlc3MvZXhwZWN0ZWQvdW5pb24ub3V0ICAgIHwgMTcg KysrKysrKysrCnNyYy90ZXN0L3JlZ3Jlc3Mvc3FsL3VuaW9uLnNxbCAgICAgICAgIHwgIDYgKysr CjMgZmlsZXMgY2hhbmdlZCwgNTMgaW5zZXJ0aW9ucygrKSwgMzggZGVsZXRpb25zKC0pCgo= --===============6319620624911300359==--