[PATCH 08/14] Store the number of subtransactions in xl_running_xacts separately from toplevel xids

Andres Freund <andres@2ndquadrant.com>

From: Andres Freund <andres@2ndquadrant.com>

To: pgsql-hackers@postgresql.org

Date: 2012-11-15T01:17:08Z

Lists: pgsql-hackers

Attachments

0008-Store-the-number-of-subtransactions-in-xl_running_xa.patch (text/x-patch) patch 0008

To avoid complicating logic we store both, the toplevel and the subxids, in
->xip, first ->xcnt toplevel ones, and then ->subxcnt subxids.
Also skip logging any subxids if the snapshot is suboverflowed, they aren't
useful in that case anyway.

This allows to make some operations cheaper and it allows faster startup for
the future logical decoding feature because that doesn't care about
subtransactions/suboverflow'edness.
---
 src/backend/access/transam/xlog.c   |  2 ++
 src/backend/storage/ipc/procarray.c | 65 ++++++++++++++++++++++++-------------
 src/backend/storage/ipc/standby.c   |  8 +++--
 src/include/storage/standby.h       |  2 ++
 4 files changed, 52 insertions(+), 25 deletions(-)

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Background worker processes
- da07a1e85651 9.3.0 cited
Rearrange storage of data in xl_running_xacts.
- 5c11725867ac 9.3.0 cited
Basic binary heap implementation.
- 7a2fe9bd0371 9.3.0 cited
Embedded list interface
- a66ee69add6e 9.3.0 cited
Refactor xlog.c to create src/backend/postmaster/startup.c
- 9aceb6ab3c20 9.2.0 cited