From: Japin Li <japinli@hotmail.com>
To: Fujii Masao <masao.fujii@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>,  wenhui qiu
 <qiuwenhuifx@gmail.com>,  pgsql-hackers <pgsql-hackers@postgresql.org>,
  John Naylor <johncnaylorls@gmail.com>,  Christoph Berg <myon@debian.org>
Subject: Re: WAL compression setting after PostgreSQL LZ4 default change
In-Reply-To: 
 <CAHGQGwGv8FLvOkTm3dpTsvt70puYpzKOmq3-YQSOpDCdZ8gyaQ@mail.gmail.com>
	(Fujii Masao's message of "Fri, 3 Jul 2026 11:58:52 +0900")
References: 
 <CAGjGUAL1b=Mwd1SCvLbo+fivEr9KDpFcu4jmqKCZXwT=6CiiGQ@mail.gmail.com>
	<akRVDdkH1ntCpTBv@paquier.xyz>
	<CAHGQGwGv8FLvOkTm3dpTsvt70puYpzKOmq3-YQSOpDCdZ8gyaQ@mail.gmail.com>
User-Agent: mu4e 1.14.1; emacs 30.2
Date: Fri, 03 Jul 2026 16:38:06 +0800
Message-ID: 
 <SY7PR01MB1092134E0AD4108661A3A65F8B6F42@SY7PR01MB10921.ausprd01.prod.outlook.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-MessageSentRepresentingType: 1
X-MS-PublicTrafficType: Email
X-MS-TrafficTypeDiagnostic: SY7PR01MB10921:EE_|ME0PR01MB9526:EE_
X-MS-Office365-Filtering-Correlation-Id: 782aca85-c1d6-4049-427a-08ded8de69c6
X-Microsoft-Antispam: 
	BCL:0;ARA:14566002|15080799012|39105399006|8060799015|19110799012|22091999003|24071999003|24121999003|55001999006|23021999003|6090799003|24021099003|25010399006|5072599009|20031999006|4140399003|40105399003|11120399003|26121999007|440099028|3412199025;
X-Microsoft-Antispam-Message-Info: 
	=?utf-8?B?TzV5REM4V2dUbjJCR3VPS0UrZFpiVmlJWjdRdVg4MmhjaWxLOUpabTFoQyt5?=
 =?utf-8?B?Tk4rRWhQR1hnTXNTT0VLVWtrZ0Vkck5aMGV6N25TMVZmcVZCdzY0Ym5SanJv?=
 =?utf-8?B?cTc4WW4yeWd6c0wrUDNkZEVhRmNwMCt1VC9KVlZyQXhNZ1luclByV2FzM3BQ?=
 =?utf-8?B?WkNkbCsrenJqWThOQmVsYzNubkVRaWU0V3lKRXZJazkxd0dTNGtzOXRIMkVi?=
 =?utf-8?B?MG9vWHB1V2Rud0xwWVc0bzFmc1VDKzVBT0xLRFJSa3liRUhlWEZ0ZDNGUU5M?=
 =?utf-8?B?S2NyalpRS25lY2l2NHdrdG8rZnJNb3VMY1ZGM3hERm1BQ0FaUjlPWUc4U3Y1?=
 =?utf-8?B?dVgvQzVjbE1YQ1N3UW9zTkNpRTRNMDFzcHN3SkpNL3hScDRLaWhmRmJJSFZS?=
 =?utf-8?B?TUcraWorNGhWbWhJT2gwa0FNQmVNRW51azdWaTlTUGZ1UXpzRDVJVzRrbU9x?=
 =?utf-8?B?Z0VHajROeER6bmNheDJtM2tuelRlcnpVNW9GeHJnTlZ4eHhDMnJwajkrYUEw?=
 =?utf-8?B?c0VrRkY1YzA3Rzk3Vnc5ZGdPTU94Sy9OVWVEUkJIbFk0aDNPQVMrOTl2UmRz?=
 =?utf-8?B?VmxtZVBlMzhHQXovWkU0NDRPOEEzWkw3WjRSZy9FN0ptTGNLL2tCaTVXS3dN?=
 =?utf-8?B?Z1Yzc25hNmQvaDhJR2tmczZDTnZ6WGVoMXVUQm1OVjgzVHNGcHoySzJ6ejRZ?=
 =?utf-8?B?K0RxU0E4ekdRMTZsVjBia2dpd1pscjV2TGJVeGVzL29MNk5LS2YxYlFuQmVJ?=
 =?utf-8?B?RVJOeGl6d0dWek9CaXBudHNaVk1iMUc1MXFWclc1NFE0bFIzWTlXd3lOSjAr?=
 =?utf-8?B?bDIxZWZkbUhaS0l0MVlBejJ2SGMycWtob2ZSSmRieWw1TjFOY3ZjcmlYM1VK?=
 =?utf-8?B?a1hMQzVxN0x4VSsvaGxPL1ZnaGVJSzN6OUNzWlRTL2RaWTh5L0FHaVhzRWVu?=
 =?utf-8?B?OEM5Z2lzSXcyZU40MSs3WG10YjhudXBDeXFvd0VSN21xT3A3bFhyUWM4WTAw?=
 =?utf-8?B?UDh4MGhRcENWRXVwcnY4U1hhcnl6RjloSVBESDhuL2w5NUNYV2JNZnRLNHRE?=
 =?utf-8?B?QmRkVzBnemtJOWloQzZyeXNQWHJkYklsMDdGcmNIS1pmNUFtVFBXN3BQVXRR?=
 =?utf-8?B?MkUzR0VlL1g2RUxZL0wyMXBZRC8xa2VPQUJoN1dDYXp5VHhzYnVYelJ3MTA1?=
 =?utf-8?B?dUVNcWswaUpINGpoMjlyeVNjRHNocE9rSHpsRFVVcHc4VjdleGY2OWY1dGI3?=
 =?utf-8?B?dGpoREJYUWoyT1RDdlY4NkZEU1RhWnRwbDgyQXBvQk15N09iSkNMejg0Yzg1?=
 =?utf-8?B?YUg3a0dLOWlBUFBMTmJ3QVJPc3V4b1psR1RxUVVGTWtNWTBGaHpnWnBPNUov?=
 =?utf-8?B?a3J2VlJZYjhxcDUrUkl0K1lEK1F3aU5DVnVRalprb2RydHFreGJqUG4zQVlI?=
 =?utf-8?B?RTYrSEh3V0lsRzdGdjFrR0FXUzlvaHZNdWUzcGNXR0JlUFZZRHFNL0toT3NC?=
 =?utf-8?B?NzN4d2tiYWpaUDJLajIzWFhSUzZMNnFHUVJjSVdLV05uMGE2YW92M0ZTeER3?=
 =?utf-8?B?RlJKdz09?=
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: 
	=?utf-8?B?THpJcWlDL3UvbGdQekZOdmVWVVZDb1B3c2dPdGc1TGMrQW04OUk0VTJuaDlH?=
 =?utf-8?B?cjNiYUhTeXdFZXUwckZZWkV3NTJjTkI0dm8wYU5wd3pwMWRpWFJSTE8yMFk2?=
 =?utf-8?B?YmFpWEY0dHduM2JWeGFWaCtyZUxYOTJlYjlaMXdFc2NWU2MwY1VnVWhUcXo4?=
 =?utf-8?B?QStnWGVxQys5Ri9qNDJCUEo4cmZwcUlDN1c4TzVQeE9BY3lNTGJEZ09QeHpH?=
 =?utf-8?B?ZHRONmZDdERKclJYcy9pb1BBVXl1WnFUb0JOSWE5MjNQOVJKUkpOUW9rU3h3?=
 =?utf-8?B?WFpoMnJ4U1Z0cTNvUHVqTnI5Nks3L1N4cUwxMkhoSm4rL1pjUWxDK1N5QXUy?=
 =?utf-8?B?bzBrbW41ZGE2UC9NS01hRk42Rzg4ankzbEFZQXFYZlUxbkt2S2xialU0TzR3?=
 =?utf-8?B?TDVVdTdtUmR4UjVMK3VwQjhlRXdFL1hkcGdqRlVFamVrSm5GWUJzN1RhU1F6?=
 =?utf-8?B?Qzh5dmhOeFFmRU44NkpHOVFuZHlXUHhVcDkrbFdGdS9CeVJEZXNrdTVUVlY4?=
 =?utf-8?B?RElNT0xzRG5yeWswNy8rTzJNU3UvNHl5RDVENzRteFEzaVFRV1VGQ0dvMENC?=
 =?utf-8?B?d2oyQkkwSHBVMStLcjZLbEQzQXZNN2x5QnljSDlFQVI2MmZiTlJtQUllOW1w?=
 =?utf-8?B?NlpPS0YxajlnVGJKNVNTQ1lSN3haY3FtSGVaVmRXcEdvRFlEdGljUDlrMWNR?=
 =?utf-8?B?bzVBWG9md1hteFRRZWNuK2h1WVpvaGFVY2FwUE01TVhuajB1cnMyNHhDdGtw?=
 =?utf-8?B?cVlxNkVlbWFVODRnSXlYNVZWMHp5U2FZVGhZSEV0bEx6KzAweTJiV1Y1a3VG?=
 =?utf-8?B?NkxDRmNKOCt3NVRQQlBvQlBaZDlCTUJIZmVCTzQ4Rmpyb1FGSzJwa3JuT0Vo?=
 =?utf-8?B?TWxBZS9lU1JwNTE2bERJdmZwZjNoUmNxT2YrUnBuV1hCeXdmaDR2NWRtNmZa?=
 =?utf-8?B?eU9ZQjdSWE5FU2pxUjZYQjZKNk5LRkp0LzdTUzBNVmd4YjZqY3FtWmJVZHlB?=
 =?utf-8?B?SEtPOVprKzRiLzArZ2wraFdYbE1PYXJUQndUY0ZES1BWc3doV3RJUkZkUzFu?=
 =?utf-8?B?b3RSQnhhckJKUmdhdENlbVlVSWZlTVhldVdYU21KQjhxY1dVU1hKVHd0eFh4?=
 =?utf-8?B?T3kzVmNvWlNKZzJFYlZDbDQ1azQraUdNUnhJMmJTU3VmVmRycXFCSGN4STNK?=
 =?utf-8?B?dklieTlSOTFKYzF6NSsxK2piM0ZyY3pCS1ArdGJTSXNhaWVsQjVaT3lyYllL?=
 =?utf-8?B?eEo4WFVNNmpyMUgxZlBBQzJOUG9WZmduSCszZmROWmV6QmFMem5oVXNncXNh?=
 =?utf-8?B?UVRSZGZjK2NiZ0dzc2cyM0tKOGVxS3NlV0ZjZ1hhZFQ0M3o2L3Nzcm5hd0hy?=
 =?utf-8?B?dks4M3M5Z3AyV2hYcVZkOEt3YnJmaXY3blVVSzRSZHk3SU0vK2xqOUZvdU9r?=
 =?utf-8?B?aGdaTGplZnQwaU5rR1gwS1dROWJpSGUrZUNnRGZVdWJjakdpdlN5akZidDhy?=
 =?utf-8?B?Zks4amZyODNhSmZXUjRMeTk4amg5bFZXVjVsU2l0Y1gyZFNDV1BNRUpnb1Vn?=
 =?utf-8?B?TFdReCtTUTBtbTg4U0JrNlVNd3VRM1hvV3cySXFCWThIMHRTL1R1THpLRGds?=
 =?utf-8?B?bENEU3JCRjRubU91Qm5ublFGbTd5cEhodnJkTmhvSDRTbUNhcTdBazRPY3Qw?=
 =?utf-8?B?TU9QL0U3RWhGbFlqaHJabTNxTDNTcjl4QmtVTFVnK0RXZXVPTlFCSXR0cGdU?=
 =?utf-8?B?NFFzRzlIMVM3TGUyZmRVL3Q0d2VwYmhTZ0hEWWhOT1NjV0ZlSWN0UVphclVY?=
 =?utf-8?B?VFpmQStEdmxDMTNyblRwL2cwV0xLeDA1Z1ZFTU9EYkdJV0l5UlQrL0tnVlo5?=
 =?utf-8?Q?J4mUD93xR/BdF?=
X-OriginatorOrg: sct-15-20-9412-4-msonline-outlook-feddd.templateTenant
X-MS-Exchange-CrossTenant-Network-Message-Id: 
 782aca85-c1d6-4049-427a-08ded8de69c6
X-MS-Exchange-CrossTenant-AuthSource: SY7PR01MB10921.ausprd01.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Jul 2026 08:38:10.4078
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa
X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg: 
	00000000-0000-0000-0000-000000000000
X-MS-Exchange-Transport-CrossTenantHeadersStamped: ME0PR01MB9526
List-Id: <pgsql-hackers.lists.postgresql.org>
List-Help: <https://lists.postgresql.org/manage/>
List-Subscribe: <https://lists.postgresql.org/manage/>
List-Post: <mailto:pgsql-hackers@lists.postgresql.org>
List-Owner: <mailto:pgsql-hackers-owner@lists.postgresql.org>
List-Archive: <https://www.postgresql.org/list/pgsql-hackers>
Archived-At: 
 <https://www.postgresql.org/message-id/SY7PR01MB1092134E0AD4108661A3A65F8B6F42%40SY7PR01MB10921.ausprd01.prod.outlook.com>
Precedence: bulk

On Fri, 03 Jul 2026 at 11:58, Fujii Masao <masao.fujii@gmail.com> wrote:
> On Wed, Jul 1, 2026 at 8:45=E2=80=AFAM Michael Paquier <michael@paquier.x=
yz> wrote:
>>
>> On Tue, Jun 30, 2026 at 06:25:09PM +0800, wenhui qiu wrote:
>> > The recent PostgreSQL commit changes the default TOAST compression to =
lz4
>> > when LZ4 support is available, based on the rationale that LZ4 is gene=
rally
>> > more efficient than pglz in terms of CPU usage and compression
>> > ratio.  Given that, should we also consider changing the default
>> > compression method used by wal_compression =3D on from pglz to lz4?
>>
>> "on" is just a backward-compatible value, so we could let it as-is.
>
> Yes, so +1 to leaving "on" as it is. Making its meaning depend on
> the build options seems very confusing. Users who want lz4 or zstd
> can simply specify those methods explicitly instead of using "on".
>

Understood.  I'll withdraw this from the CommitFest.

> Regards,
>
> --=20
> Fujii Masao

--=20
Regards,
Japin Li
ChengDu WenWu Information Technology Co., Ltd.