> > We intend to do the following work on the patch soon: > 1. Write a detailed README > 2. Split the patch into several pieces including a separate part for > XID_FMT. But if committers meanwhile choose to commit Jim's XID_FMT patch > we also appreciate this and will rebase our patch accordingly. > 2A. Probably refactor it to store precalculated XMIN/XMAX in memory > tuple representation instead of t_xid_base/t_multi_base > 2B. Split the in-memory part of a patch as a separate > 3. Construct some variants for leaving "double xmax" format as a temporary > one just after upgrade for having only one persistent on-disk format > instead of two. > 3A. By using SQL function "vacuum doublexmax;" > OR > 3B. By freeing space on all heap pages for pd_special before > pg-upgrade. > OR > 3C. By automatically repacking all "double xmax" pages after upgrade > (with a priority specified by common vacuum-related GUCs) > 4. Intentionally prohibit starting a new transaction with XID difference > of more than 2^32 from the oldest currently running one. This is to enforce > some dba's action for cleaning defunct transaction but not binding one: > he/she can wait if they consider these old transactions not defunct. > 5. Investigate and add a solution for archs without 64-bit atomic values. > 5A. Provide XID 8-byte alignment for systems where 64-bit atomics > is provided for 8-byte aligned values. > 5B. Wrap XID reading into PG atomic locks for remaining 32-bit ones > (they are expected to be rare). >
Hi, hackers! PFA patch with README for 64xid proposal. It is 0003 patch of the same v6, that was proposed earlier [1]. As always, I very much appreciate your ideas on this readme patch, on overall 64xid patch [1], and on the roadmap on its improvement quoted above. [1] https://www.postgresql.org/message-id/CACG%3DezZe1NQSCnfHOr78AtAZxJZeCvxrts0ygrxYwe%3DpyyjVWA%40mail.gmail.com -- Best regards, Pavel Borisov Postgres Professional: http://postgrespro.com <http://www.postgrespro.com>
v6-0003-README-for-64bit-xid.patch
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