これはPostgreSQL Advent calendar 2025の17日目の記事です。

以前PostgreSQL 18でUUIDv7がサポートされたという記事を書きました。今回は現在取り組んでいるUUIDv7の生成を早くするための改善について、その背景や検証内容についてです。

UUIDv7 was defined in RFC 9562. There are eight versions of UUID, and while they all have a size of 128 bits, the data stored in each version is different. Until I learned about UUIDv7, when I thought of UUIDs, I imagined random data - but that’s version 4 UUID. The version 7 UUID (UUIDv7) has a significant feature: sortability thanks to a timestamp stored at the beginning of the data.

これはPostgreSQL Advent calendar 2024の18日目の記事です。

The well-known implementation of the standard C library is glibc. musl libc is another implementation of the standard C library. It uses the MIT License, and it is known for its simple implementation and small binary size. It is also used in Alpine Linux.