3 ms·
...all of which structures you'd somehow need to synchronize writing to, to keep them accurate and fresh. Global write-locks do not scale, no matter how fast it
by rosser 9y ago
...all of which structures you'd somehow need to synchronize writing to, to keep them accurate and fresh. Global write-locks do not scale, no matter how fast it might be in the toy case.
- devit 9y agoIt's just an index on the transaction id fields of the rows, so it should scale like any other index on the table.
- rosser 9y agoSo, basically the already-existing Visibility Map? Indexes in postgres point to the page, not the tuple. The VM keeps two bits per page: "does this page have any 'dead' tuples?", and "does this page need to be touched for xid wraparound?" Vacuuming doesn't touch a page unless the VM indicates it's necessary.