Thread: Determining current WAL
Hi, I'm currently looking at using WAL / PITR backups for a database, and I need to keep the backups as up to date as possible. As such, keeping a copy of the current WAL file, as suggested in the manual, would seem to be a very good idea. I'm slightly confused, though, about which file is the current. I had assumed that it would always be the highest numbered, but it seems that in some cases this is not always dated as the most recently modified (this seems to occur after taking a full backup during some of my test cases). My question, then is whether I was correct in my original assumption, or whether the current WAL is in fact the most recently modified. Apologies if I'm missing something really obvious, but I've searched the mail archives and the web and haven't been able to find anything relevant. Regards Thomas Revell :.________________ CONFIDENTIALITY : This e-mail and any attachments are confidential and may be privileged. If you are not a named recipient, please notify the sender immediately and do not disclose the contents to another person, use it for any purpose or store or copy the information in any medium.
thomas.revell@powerconv.alstom.com writes: > I'm currently looking at using WAL / PITR backups for a database, and I > need to keep the backups as up to date as possible. As such, keeping a > copy of the current WAL file, as suggested in the manual, would seem to be > a very good idea. I'm slightly confused, though, about which file is the > current. I had assumed that it would always be the highest numbered, No. Go with the most-recently-modified. Segment files are normally created (or renamed into place) in advance of being needed. There should probably be a cleaner/more reliable way of identifying the active file ... regards, tom lane
OK, thanks. thomas.revell@powerconv.alstom.com writes: > I'm currently looking at using WAL / PITR backups for a database, and I > need to keep the backups as up to date as possible. As such, keeping a > copy of the current WAL file, as suggested in the manual, would seem to be > a very good idea. I'm slightly confused, though, about which file is the > current. I had assumed that it would always be the highest numbered, No. Go with the most-recently-modified. Segment files are normally created (or renamed into place) in advance of being needed. There should probably be a cleaner/more reliable way of identifying the active file ... regards, tom lane :._______________ CONFIDENTIALITY : This e-mail and any attachments are confidential and may be privileged. If you are not a named recipient, please notify the sender immediately and do not disclose the contents to another person, use it for any purpose or store or copy the information in any medium.
Tom Lane wrote: > thomas.revell@powerconv.alstom.com writes: > >>I'm currently looking at using WAL / PITR backups for a database, and I >>need to keep the backups as up to date as possible. As such, keeping a >>copy of the current WAL file, as suggested in the manual, would seem to be >>a very good idea. I'm slightly confused, though, about which file is the >>current. I had assumed that it would always be the highest numbered, > > > No. Go with the most-recently-modified. Segment files are normally > created (or renamed into place) in advance of being needed. > > There should probably be a cleaner/more reliable way of identifying > the active file ... Yes it was discussed during the attempt to create the log delivery to another server in "replay" state, if the master was not responding then it was usefull have a way to identify the active wal segment, at the time I was identifing the current wall the last created one Regards Gaetano Mendola