As the README for xlog says: There're two kinds of WAL records: * WAL record that contains enough information to re-generate the entire contents of a page;
during recovery of these records, blocks are read with: buffer = XLogReadBuffer(reln, blkno, true); so it can be sure that the block will be read successfully, i.e. buffer won't be InvalidBuffer * WAL record provides only enough information to incrementally update the page; As all blocks related to these xlog records will be backed up in the xlog during the first write after checkpoint, and RestoreBkpBlocks will also read it in with : buffer = XLogReadBuffer(reln, blkno, true); so it also can be sure that these blocks will be read successfully: because the fisrt read of it must be in RestoreBkpBlocks, which will reconstruct the block validly, and none problems in later read. Then if we come to the path "log_invalid_page", can I say there must be sth wrong, and we should PANIC? ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
