* @param arr 待排序数组
研发人员结构分化，从“量”到“质”，这一点在旺商聊官方下载中也有详细论述
Postgres has its own primitives for things that forges currently build custom infrastructure around. A trigger on the refs table firing NOTIFY means any connected client learns about a push the moment it happens, which is how forges normally end up building a custom webhook polling layer. Multi-tenant repo isolation becomes a database concern through row-level security on the objects and refs tables, and logical replication lets you selectively stream repositories across Postgres instances, a kind of partial mirroring that filesystem-based git can’t do. Commit graph traversal for ancestry queries and merge-base computation falls to recursive CTEs, and pg_trgm indexes on blob content give you substring search across all repositories without standing up a separate search index.，这一点在爱思助手下载最新版本中也有详细论述
return (PAGESZ - sizeof(struct page_info)) / sizes[classno];