On Mon, 2023-04-03 at 14:51 +0800, Dawn Yu wrote: > Recently，we come up with a same problem，when the database make the checkpoint, > the size of wal directory increase very fast and take one hundred percent disk > usage,we found the problem of pg wal write amplification is very serious. > By analyzing the wal log, in some scenarios, most of the space is wasted when > maintaining the full page of the index. Has the community considered modifying > this part of the relevant code to make the full page better,The setting of FPW > function is divided into two parts, the full-page write of the data record and > the full-page write of the index block, and the switch functions can be set > separately. > By default, index full-page write is disabled. If the index is broken, you can > rebuild the index to solve it. Although the security of index data cannot be > guaranteed, this setting can greatly reduce the problem of storage space explosion > caused by wal write amplification. I would feel funny about a parameter like that. There are a couple of things you can do today: - increase "max_wal_size" and "checkpoint_timeout" to get checkpoints less often - activate "wal_compression", so that the FPW are compressed. Best is to use v15, where you can use "lz4" or "zstd" compression, which are much faster. Yours, Laurenz Albe
