What happens if a replacement string happens to be split in the middle by the fgets buffering? I think it'll fail to be replaced. This applies to both versions.
In the stringinfo version it seemed to me that using pnstrdup is possible to avoid copying trailing bytes. If you're asking for opinion, mine is that StringInfo looks to be the better approach, and also you don't need to keep API compatibility. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
