QEMU migration and HMP cuts, PostgreSQL replication fixes

QEMU development led the day with patch series on faster snapshot restore, optional HMP, and confidential RISC-V VMs. PostgreSQL threads centered on a logical replication bug with toasted columns and a proposal for eager WAL preallocation.

QEMU fast snapshot load via postcopy and userfaultfd

A fifth-round QEMU patch series adds fast snapshot load that uses postcopy migration together with userfaultfd for lazy RAM restore. The approach aims to cut the time needed to resume a VM from a snapshot by bringing pages in on demand. Migration and snapshot users should track the series for lower restore latency.

Making HMP compile-time optional in QEMU

A 49-patch series proposes turning the Human Monitor Protocol into a compile-time option controlled by --disable-hmp, with a longer path toward a standalone build. The stated goal is a smaller attack surface for deployments that never need HMP. Four participants iterated on the design across dozens of messages.

Logical replication row filters null unchanged toasted columns

PostgreSQL hackers examined a bug in which row filters on logical replication turn unchanged toasted columns into NULL on the subscriber. The thread mixes diagnosis with fix discussion among seven participants. Sites that filter large attributes during logical replication risk silent data loss until a fix lands.

QEMU KVM support for RISC-V CoVE confidential VMs

An RFC series of 17 patches adds KVM CoVE confidential VM support to QEMU's RISC-V target, modeled on existing SEV and TDX paths. The work brings confidential computing primitives to RISC-V guests under KVM. Early review is under way between two participants.

pg_wal_preallocate SQL function for eager WAL segments

A patch proposes a superuser SQL function pg_wal_preallocate() that creates future WAL segments ahead of need. Discussion covers the interface, limits tied to max_wal_size, and whether automatic alternatives would be preferable. Operators facing WAL creation stalls during bursts may find the knob useful.

Hexagon semihosting support in QEMU

A 13-patch series implements the semihosting ABI and accompanying tests for Hexagon system emulation in QEMU. The work lets Hexagon guests use semihosting services under system mode. Three participants reviewed the third revision.

guest-memfd init-shared backends for KVM

A fourth revision of a QEMU series adds guest-memfd=on support to memory-backend-memfd so fully shared guest memory can back KVM VMs. The change extends hostmem options for confidential and shared-memory setups. Five participants continue refining the patches.

EXCEPT clause for TABLES IN SCHEMA publications

Review continued on a PostgreSQL patch that adds EXCEPT support when publishing TABLES IN SCHEMA. The latest messages focus on code comments and small refinements rather than new design. Six participants kept the iteration moving.