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fix: preserve reader grants across ash.rebuild_partitions() (#213) #218

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fix: preserve reader grants across ash.rebuild_partitions() (#213) #218

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256 changes: 256 additions & 0 deletions .github/workflows/test.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -3000,6 +3000,262 @@ jobs:
$$;
EOF

- name: "Issue #213: rebuild_partitions preserves reader grants"
env:
PGPASSWORD: postgres
run: |
# A rebuild drops and recreates query_map_all plus every sample_N /
# query_map_N relation. The outage used to be latent: empty storage
# let readers appear healthy until the first sample made status()
# touch the freshly-created, ungranted query_map_all view. Drive that
# path before inspecting ACLs so this test fails on the user-visible
# bug, not only on a catalog difference.
psql -h localhost -U postgres -d postgres -v ON_ERROR_STOP=1 << 'EOF'
do $$
begin
if not exists (
select from pg_roles where rolname = 'cx213_rebuild_reader'
) then
create role cx213_rebuild_reader;
end if;
if not exists (
select from pg_roles where rolname = 'cx213_rebuild_partial'
) then
create role cx213_rebuild_partial;
end if;
if not exists (
select from pg_roles where rolname = 'cx213_rebuild_none'
) then
create role cx213_rebuild_none;
end if;
end $$;

select ash.grant_reader('cx213_rebuild_reader');
grant select on ash.query_map_0 to cx213_rebuild_partial
with grant option;
grant select on ash.sample_1 to cx213_rebuild_partial;

do $$
declare
v_acl text[];
v_full_acl constant text[] := array[
'query_map_0:false', 'query_map_1:false',
'query_map_2:false', 'query_map_all:false',
'sample_0:false', 'sample_1:false', 'sample_2:false'
];
v_role constant name[] := array[
'cx213_rebuild_reader'::name, 'pg_monitor'::name,
'cx213_rebuild_partial'::name, 'cx213_rebuild_none'::name
];
v_expected text[];
begin
for i in 1 .. cardinality(v_role) loop
v_expected := case
when i <= 2 then v_full_acl
when i = 3 then array['query_map_0:true', 'sample_1:false']
else array[]::text[]
end;
select coalesce(
array_agg(
relation.relname || ':' || acl.is_grantable
order by relation.relname
),
array[]::text[]
)
into v_acl
from pg_class as relation
join pg_namespace as nsp on nsp.oid = relation.relnamespace
cross join lateral aclexplode(relation.relacl) as acl
join pg_roles as grantee on grantee.oid = acl.grantee
where nsp.nspname = 'ash'
and (relation.relname = 'query_map_all'
or relation.relname ~ '^query_map_[0-9]+$'
or relation.relname ~ '^sample_[0-9]+$')
and acl.privilege_type = 'SELECT'
and grantee.rolname = v_role[i];
assert v_acl = v_expected,
format('%s pre-rebuild ACL: expected %s, got %s',
v_role[i], v_expected, v_acl);
end loop;
end $$;

select ash.rebuild_partitions(4, 'yes');
update ash.config set sampling_enabled = true where singleton;
EOF

PGAPPNAME=cx213_rebuild_probe \
psql -h localhost -U postgres -d postgres \
-c "select pg_sleep(30)" >/dev/null 2>&1 &
probe_pid=$!
trap 'kill "$probe_pid" 2>/dev/null || true; wait "$probe_pid" 2>/dev/null || true' EXIT

active_probe=0
for _ in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20; do
active_probe=$(psql -h localhost -U postgres -d postgres -tAX \
-c "select count(*) from pg_stat_activity
where application_name = 'cx213_rebuild_probe'
and state = 'active'")
if [ "$active_probe" = "1" ]; then
break
fi
sleep 0.25
done
if [ "$active_probe" != "1" ]; then
echo "Expected exactly one active sampler probe, got: $active_probe" >&2
exit 1
fi

sampled=$(psql -h localhost -U postgres -d postgres -tAX \
-v ON_ERROR_STOP=1 -c "select ash.take_sample()")
if [ "$sampled" != "1" ]; then
echo "Expected ash.take_sample() to insert exactly 1 row, got: $sampled" >&2
exit 1
fi
terminated=$(psql -h localhost -U postgres -d postgres -tAX \
-v ON_ERROR_STOP=1 \
-c "select count(*)
from (
select pg_terminate_backend(pid) as stopped
from pg_stat_activity
where application_name = 'cx213_rebuild_probe'
) as probe
where stopped")
if [ "$terminated" != "1" ]; then
echo "Expected to terminate exactly 1 sampler probe, got: $terminated" >&2
exit 1
fi
wait "$probe_pid" 2>/dev/null || true
trap - EXIT

psql -h localhost -U postgres -d postgres -v ON_ERROR_STOP=1 << 'EOF'
set role cx213_rebuild_reader;
do $$
declare
v_status_version text;
v_status_samples text;
v_status_partitions text;
v_sample record;
begin
select value into strict v_status_version
from ash.status() where metric = 'version';
assert v_status_version = '2.0-beta1',
format('named reader status version: expected 2.0-beta1, got %s',
v_status_version);
select value into strict v_status_samples
from ash.status() where metric = 'samples_total';
assert v_status_samples = '1',
format('named reader status samples_total: expected 1, got %s',
v_status_samples);
select value into strict v_status_partitions
from ash.status() where metric = 'num_partitions';
assert v_status_partitions = '4',
format('named reader status num_partitions: expected 4, got %s',
v_status_partitions);

select count(*) as rows,
min(database_name) as database_name,
min(active_backends) as active_backends,
min(wait_event) as wait_event
into v_sample
from ash.samples(
now() - interval '1 hour', now() + interval '1 second'
);
assert v_sample.rows = 1,
format('named reader samples(): expected 1 row, got %s',
v_sample.rows);
assert v_sample.database_name = 'postgres',
format('named reader samples(): expected database postgres, got %s',
v_sample.database_name);
assert v_sample.active_backends = 1,
format('named reader samples(): expected active_backends 1, got %s',
v_sample.active_backends);
assert v_sample.wait_event = 'Timeout:PgSleep',
format('named reader samples(): expected Timeout:PgSleep, got %s',
v_sample.wait_event);
end $$;
reset role;

set role pg_monitor;
do $$
declare
v_status_version text;
v_status_samples text;
v_sample_count bigint;
begin
select value into strict v_status_version
from ash.status() where metric = 'version';
assert v_status_version = '2.0-beta1',
format('pg_monitor status version: expected 2.0-beta1, got %s',
v_status_version);
select value into strict v_status_samples
from ash.status() where metric = 'samples_total';
assert v_status_samples = '1',
format('pg_monitor status samples_total: expected 1, got %s',
v_status_samples);
select count(*) into v_sample_count
from ash.samples(
now() - interval '1 hour', now() + interval '1 second'
);
assert v_sample_count = 1,
format('pg_monitor samples(): expected 1 row, got %s',
v_sample_count);
end $$;
reset role;

do $$
declare
v_acl text[];
v_full_acl constant text[] := array[
'query_map_0:false', 'query_map_1:false',
'query_map_2:false', 'query_map_3:false',
'query_map_all:false', 'sample_0:false',
'sample_1:false', 'sample_2:false', 'sample_3:false'
];
v_role constant name[] := array[
'cx213_rebuild_reader'::name, 'pg_monitor'::name,
'cx213_rebuild_partial'::name, 'cx213_rebuild_none'::name
];
v_expected text[];
begin
for i in 1 .. cardinality(v_role) loop
v_expected := case
when i <= 2 then v_full_acl
when i = 3 then array['query_map_0:true', 'sample_1:false']
else array[]::text[]
end;
select coalesce(
array_agg(
relation.relname || ':' || acl.is_grantable
order by relation.relname
),
array[]::text[]
)
into v_acl
from pg_class as relation
join pg_namespace as nsp on nsp.oid = relation.relnamespace
cross join lateral aclexplode(relation.relacl) as acl
join pg_roles as grantee on grantee.oid = acl.grantee
where nsp.nspname = 'ash'
and (relation.relname = 'query_map_all'
or relation.relname ~ '^query_map_[0-9]+$'
or relation.relname ~ '^sample_[0-9]+$')
and acl.privilege_type = 'SELECT'
and grantee.rolname = v_role[i];
assert v_acl = v_expected,
format('%s post-rebuild ACL: expected %s, got %s',
v_role[i], v_expected, v_acl);
end loop;
end $$;

select ash.rebuild_partitions(3, 'yes');
update ash.config set sampling_enabled = true where singleton;
drop owned by cx213_rebuild_reader, cx213_rebuild_partial,
cx213_rebuild_none;
drop role cx213_rebuild_reader;
drop role cx213_rebuild_partial;
drop role cx213_rebuild_none;
EOF

- name: "Test v1.4: array merge helpers"
env:
PGPASSWORD: postgres
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10 changes: 7 additions & 3 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -373,9 +373,13 @@ select ash.rebuild_partitions(9, 'yes');
select ash.start();
```

`rebuild_partitions()` drops all raw samples and query-map partitions. Rollups
survive. Re-run `ash.grant_reader()` for monitoring roles afterward because
new partitions need fresh grants.
`rebuild_partitions()` drops and recreates all raw-sample and query-map
relations, including the `query_map_all` view. Rollups survive. Existing
reader bundles are preserved automatically, including the installer's default
`pg_monitor` grant; partial manual grants are restored only on the same
relation names and are not widened. Older 2.0-beta1 builds did not preserve
these grants: after a rebuild on one of those builds, re-run
`ash.grant_reader()` for each reader role, including `pg_monitor`.

Typical storage at 1-second sampling:

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