Hi, as many before, I ran into the issue of a postgresql database (8.4.1) - committing many transactions - to huge volume tables (3-figure GB in size) - running the xid wrap vacuum (to freeze tuples)
where the additional read IO load has negative impact to the extent of the system becoming unusable. Besides considering the fact that this can be worked around by exchanging printed sheets of paper or plastic (hello to .au) for hardware, I'd very much appreciate answers to these questions: * have I missed any more recent improvements regarding this problem? My understanding is that the full scan for unfrozen tuples can be made less likely (by reducing the number of transactions and tuning the autovac), but that it is still required. Is this correct? * A pretty obvious idea seems to be to add special casing for "fully frozen tables": If we could register the fact that a table is fully frozen (has no new tuples after the complete-freeze xid), a vacuum would get reduced to just increasing that "last frozen" xid. It seems like Alvaro Herrera had implemented a patch along the lines of this idea but I fail to find any other references to it: http://grokbase.com/t/postgresql/pgsql-hackers/0666gann3t/how-to-avoid-transaction-id-wrap#200606113hlzxtcuzrcsfwc4pxjimyvwgu Does anyone have pointers what happened to the patch? Thanks, Nils -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
