Re: Undo worker and transaction rollback

On Thu, Oct 11, 2018 at 11:30 AM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> Hello, hackers,
>
> In previous threads[1], we proposed patches for generating and storing
> undo records and now for undo-worker and the transaction rollback
> stuff. The idea is that undo remains relevant as long as the
> transaction is in progress and needs to be removed once it becomes
> irrelevant. Specifically, for a committed transaction, it remains
> relevant until the transaction becomes all-visible; zheap will use
> this for MVCC purposes. However, for an aborted transaction, it
> remains relevant until the “undo actions" described by the undo
> records have been performed. This patch introduces code to discard
> undo when it is no longer needed and reuse the associated storage.
> Additionally, this patch adds code to execute undo actions. Let me
> explain the finer details for each of the cases covered,

Latest rebased patch for undo worker and transaction rollback. This
patch includes some bug fixes from the main zheap branch and also
include code for executing undo action using RMGR (RMGR related code
is merged from Thomas' patch set for "POC: Cleaning up orphaned files
using undo logs"[1]. This patch can be applied on top of undolog and
undo-interface patches.

[1] https://www.postgresql.org/message-id/flat/CAEepm=0ULqYgM2aFeOnrx6YrtBg3xUdxALoyCG+XpssKqmezug(at)mail(dot)gmail(dot)com

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com