"Florian G. Pflug" <[EMAIL PROTECTED]> writes: > I propose to do the following in my lazy XID assignment patch - can > anyone see a hole in that?
Cleaning up this area seems like a good idea. Just FYI, one reason why there are so many LastRec pointer variables is that the WAL record format used to include a back-link to the previous record of the same transaction, so we needed to track that location. Since that's gone, simplification is definitely possible. A lot of the other behavior you're looking at "just grew" as incremental optimizations added over time. One comment is that at the time we make an entry into smgr's pending-deletes list, I think we might not have acquired an XID yet --- if I understand your patch correctly, a CREATE TABLE would acquire an XID when it makes its first catalog insertion, and that happens after creating the on-disk table file. So it seems like a good idea for smgr itself to trigger acquisition of an XID before it makes a pending-deletes entry. This ensures that you can't have a situation where you have deletes to record and no XID; otherwise, an elog between smgr insertion and catalog insertion would lead to just that. > .) Rename ProcLastRecEnd to XactLastRecEnd, and reset when starting > a new toplevel transaction. I'm not very happy with that name for the variable, because it looks like it might refer to the last transaction-controlled record we emitted, rather than the last record of any type. Don't have a really good suggestion though --- CurXactLastRecEnd is the best I can do. One thought here is that it's not clear that we really need a concept of transaction-controlled vs not-transaction-controlled xlog records anymore. In CVS HEAD, the *only* difference no_tran makes is whether to set MyLastRecPtr, and you propose removing that variable. This seems sane to me --- the reason for having the distinction at all was Vadim's plan to implement transaction UNDO by scanning its xlog records backwards, and that idea is as dead as a doornail. So we could simplify matters conceptually if we got rid of any reference to such a distinction. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster