PostgreSQL replication fixes and QEMU KVM model work

PostgreSQL hackers advanced patches for logical decoding, replication slot safety, backup verification, and TOAST addressing. QEMU developers continued architecture-specific series for aarch64 KVM host modeling, LoongArch LVZ TCG support, and multi-target QOM availability checks.

Logical decoding DDL and subtransaction bug

A fifth version of a patch for PostgreSQL bug 19555 is under review on pgsql-hackers. The change addresses an assert failure in logical decoding when DDL interacts with subtransactions and tuple CIDs, with discussion of backporting to all stable branches. Readers who run logical replication should watch this because incorrect decoding under mixed DDL and subtransactions can break change streams on production clusters.

Replication slot invalidation persistence order

Hackers are reviewing a patch that persists replication slot invalidations to disk before publishing the corresponding shared-memory state. The ordering fix prevents restart inconsistencies that arise when an invalidation is visible in memory but lost after a crash. The work matters for operators who rely on slots remaining coherent across failovers and unclean shutdowns.

Truncated compressed backup detection

A patchset on pgsql-hackers corrects pg_verifybackup so it reliably detects truncated backups compressed with zstd, gzip, or lz4. Reviewers discussed tests and edge cases around incomplete archive streams. Backup verification tools that miss truncated compressed files can give a false sense of restore readiness.

Direct TOAST addressing v2

Version 2 of a proposal introduces direct TID addressing for TOAST tuples in PostgreSQL, aiming to reduce index lookups and write amplification without a data migration step. Seven participants examined the design and its performance tradeoffs. Large-object and wide-row workloads stand to benefit if the approach lands with acceptable complexity.

Logical replication conflict log history

Discussion continues on v77 of patches that add a conflict log history table for logical replication, including fixes for tuple size limits and JSON serialization edge cases. Twelve participants refined the schema and error handling. Sites that need auditable conflict records for multi-master or failover topologies have a concrete design under active polish.

Customizable aarch64 KVM host model

A ninth revision of a 26-patch QEMU series adds SYSREG_* properties to the aarch64 KVM host model so ID registers become writable and migration can be more flexible. Three developers iterated on the property surface and host model behavior. The change helps nested and heterogeneous aarch64 setups that must expose or migrate specific CPU feature bits.

LoongArch LVZ support in TCG

Version 5 of a 23-patch series brings LVZ extension support to LoongArch TCG in QEMU, enabling nested KVM-on-TCG emulation. The single-author series covers the instruction and system-register plumbing required for the extension. Emulator users targeting LoongArch nested virtualization gain a path that does not depend solely on hardware KVM.

TargetInfo in QOM is_available callbacks

An eight-patch QEMU series passes TargetInfo into the QOM is_available callback so availability checks work correctly for multi-target combined binaries. Four participants reviewed the refactoring of target-dependent object exposure. The cleanup reduces incorrect feature visibility when a single QEMU binary covers several architectures.