Concretely, I propose to have a new struct like typedef struct xlogReaderFuncs { XLogPageReadCB read_page; XLogSegmentOpenCB open_segment; XLogSegmentCloseCB open_segment; } xlogReaderFuncs;
#define XLOGREADER_FUNCS(...) &(xlogReaderFuncs){__VA_ARGS__} and then invoke it something like xlogreader = XLogReaderAllocate(wal_segment_size, NULL, XLOGREADER_FUNCS(.readpage = &read_local_xlog_page, .opensegment = &wal_segment_open), .closesegment = &wal_segment_close), NULL); (with suitable definitions for XLogSegmentOpenCB etc) so that the support functions are all available at the xlogreader level, instead of "open" being buried at the read-page level. Any additional support functions can be added easily. This would give xlogreader a simpler interface. If people like this, I could make this change for pg13 and avoid changing the API again in pg14. Thougths? -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services