Release 2026.8.1 with PostgreSQL 19 beta 2 support

[NikolayS]

Prepare postgres_dba 2026.8.1 with PostgreSQL 19 beta 2 support.

Acceptance criteria:

• Add the exact PostgreSQL 19 beta 2 image to CI.
• Execute all 34 reports, including interactive role reports.
• Exercise normal and wide output modes with SQL errors treated as failures.
• Keep PostgreSQL 13 through 18 coverage green.
• Update compatibility documentation and release notes.

[tembo]

PR #97 already addresses this — it adds 19beta2 to the CI matrix, switches from the GitHub services block to a docker run step (needed for the beta tag + shared_preload_libraries=pg_stat_statements), and adds a dedicated interactive-role-report test step. A few things worth noting as that PR is reviewed:

The old "wide mode" CI step was not actually testing wide mode. It wrote \set postgres_dba_wide true to ~/.psqlrc, but psql was invoked with --no-psqlrc (which skips that file). Even if it had loaded, warmup.psql:29 reads postgres_dba.wide as a GUC via current_setting('postgres_dba.wide', true), not as a psql variable — so \set would have had no effect. The PR fixes this correctly by using PGOPTIONS='-c postgres_dba.wide=on'. Worth being aware that prior "wide mode green" CI runs were effectively normal-mode runs.

No ON_ERROR_STOP in the old CI. Without --set=ON_ERROR_STOP=1, psql continues past SQL errors and exits 0, so report errors were silently swallowed. The PR adds it — good, since the acceptance criteria call for SQL errors as failures. Note that this may surface previously-hidden failures on PG 13–18 that were masked before.

s1/s2 version gating. sql/s1_pg_stat_statements_top_total.sql:56 branches on :postgres_dba_pgvers_17plus to pick shared_blk_read_time vs blk_read_time. On PG 19 this flag is true, so it uses shared_blk_read_time — correct as long as the pg_stat_statements extension is v1.11+. As noted in #95 (item 9), this should ideally gate on the extension version (pg_extension.extversion), not the server version, since a PG 17+ server with an older extension will still error. The PR preloads and creates the extension in CI, so it won't catch the mismatch case.

Related open issues that remain relevant:

• :postgres_dba_interactive_mode in sql/t1_tuning.sql expected to be set by user? #92 / Code review: bugs, style violations, and gaps found in full project audit #95 (item 1): sql/t1_tuning.sql:7 does \if :postgres_dba_interactive_mode but this variable is never defaulted in warmup.psql, so standalone psql -f warmup.psql -f sql/t1_tuning.sql crashes. The PR sets it via --set in CI, masking but not fixing the standalone crash.
• Code review: bugs, style violations, and gaps found in full project audit #95 (item 8): sql/b1_table_estimation.sql:22 misses arm64/aarch64 in its architecture regex — bloat estimates will be wrong on ARM (Graviton/Ampere), including on PG 19.
• Code review: bugs, style violations, and gaps found in full project audit #95 (item 3): Reports s1/s2/s3, m1, b3/b4 emit raw catalog errors when their extensions are missing. CI installs all extensions, so this won't be caught.

Release notes. The PR replaces the entire 7.0 release notes in RELEASE_NOTES.md with just the 2026.8.1 entry. The 7.0 content (new corruption reports, report renames, terminology changes) is substantial — consider preserving it above the new section rather than deleting it, since users upgrading from pre-7.0 would lose that changelog.

Badge text. The README badge changes to PostgreSQL-13–19beta2, which is a bit awkward while 19 is still in beta. May want to revisit once 19 goes GA.