Hi -hackers, Enclosed is a patch to allow extraction/saving of FPI from the WAL stream via pg_waldump.
Description from the commit: Extracts full-page images from the WAL stream into a target directory, which must be empty or not exist. These images are subject to the same filtering rules as normal display in pg_waldump, which means that you can isolate the full page writes to a target relation, among other things. Files are saved with the filename: <lsn>.<ts>.<db>.<rel>.<blk> with formatting to make things somewhat sortable; for instance: 00000000-010000C0.1663.1.6117.0 00000000-01000150.1664.0.6115.0 00000000-010001E0.1664.0.6114.0 00000000-01000270.1663.1.6116.0 00000000-01000300.1663.1.6113.0 00000000-01000390.1663.1.6112.0 00000000-01000420.1663.1.8903.0 00000000-010004B0.1663.1.8902.0 00000000-01000540.1663.1.6111.0 00000000-010005D0.1663.1.6110.0 It's noteworthy that the raw images do not have the current LSN stored with them in the WAL stream (as would be true for on-heap versions of the blocks), nor would the checksum be valid in them (though WAL itself has checksums, so there is some protection there). This patch chooses to place the LSN and calculate the proper checksum (if non-zero in the source image) in the outputted block. (This could perhaps be a targetted flag if we decide we don't always want this.) These images could be loaded/inspected via `pg_read_binary_file()` and used in the `pageinspect` suite of tools to perform detailed analysis on the pages in question, based on historical information, and may come in handy for forensics work. Best, David
v1-pg_waldump-save-fpi.patch
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