On Sun, May 4, 2025 at 8:54 AM Nikhil Kumar Veldanda <veldanda.nikhilkuma...@gmail.com> wrote: > I agree. Each compression algorithm can decide its own metadata size > overhead. Callbacks can provide this information as well rather than > storing in fixed length bytes(3 bytes). The revised patch introduces a > "toast_cmpid_meta_size(const varatt_cmp_extended *hdr)", which > calculates the metadata size.
I don't understand why we need this. I don't see why we need any sort of generalized concept of metadata at all here. The zstd-dict compression method needs to store a four-byte OID, so let it do that. But we don't need to brand that as metadata; and we don't need a method for other parts of the system to ask how much metadata exists. At least, I don't think we do. -- Robert Haas EDB: http://www.enterprisedb.com
