![]() ![]() Each back up with tar contains a time stamp.The first line is the so-called Shebang, which informs the operating system which interpreter program it should use.So that you understand exactly what the script is accomplishing, we’ll explain it line for line: Requires a previously created list: -X.list pay attention to capitalisationĬreates a log of all directories, including checksums Specified after the creation command with -exclude= The size is output in kilobytes pay attention to capitalisationĬhecks the archive after it’s been writtenĪrchives all files from the root directory Outputs the location from which the files should be extractedĬreates, displays, or extracts a multi-part archiveĬhanges the medium to a specific file size (extract) The files remain in the archiveĪttaches the files of an existing archive to another Only attaches files that are younger than their respective versions in the archiveĭisplays detailed information about the archiving (recreate) The file is attached to the back of the archive only functions with an uncompressed archive ![]() Maintains access privileges while extracting Prevents files from overwriting already existing files when extracting from the archive Xz needs to already be installed pay attention to capitalisation (file) This option always has to be entered last, since all subsequent entries are interpreted as filesĬompresses or decompresses the archive directly with gzipĬompresses or decompresses the archive directly with compressĬompress needs to already be installed pay attention to capitalisationĬompresses or decompresses the archive directly with bzip2Ĭompresses or decompresses the archive directly with xz Writes an archive in the given file or reads the data out from the given file However, the number returned there is actually the "time since the last replayed transaction from the master" - so if the master hasn't had a transaction in awhile that "time" might make it seem like the slave is falling behind (when it reality, it is caught up, but there have been no transactions on the master.Compares files in the archive and in the file system with one another Pg_last_xact_replay_timestamp())) AS time_lag On the slave you can get an idea of the time delay using the query: SELECT extract(epoch from (now(). ![]() Of course, if the slave is replaying slowly it might never catch up - but you can measure if it is "catching up" or "falling behind" (sort of) using the query below: Technically it's "possible" for a slave to catch up with the master if the log files that the slave needs are still available on the master. You could locate the current WAL file name in use using: select pg_xlogfile_name(pg_current_xlog_insert_location()) The part before the "/" is multiplied by 'ff000000' and added to the second part: If you take the output of: SELECT pg_current_xlog_location() you'll get something like: 70/A9002358 The log unit are in bytes (though they are relative - so they aren't useful for measuring anything other than "offsets", and there sometimes can be "jumps" where there's a lot of skipped bytes), with the value being computed as:
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