When I queried `system.metrics` table, I found some negative values which hint to some potential internal overflows.

```
SELECT *
FROM system.metrics
FORMAT Vertical

...

Row 31:
───────
metric:      MemoryTrackingInBackgroundProcessingPool
value:       -580863171
description: Total amount of memory (bytes) allocated in background processing pool (that is dedicated for backround merges, mutations and fetches). Note that this value may include a drift when the memory was allocated in a context of background processing pool and freed in other context or vice-versa. This happens naturally due to caches for tables indexes and doesn't indicate memory leaks.

Row 32:
───────
metric:      MemoryTrackingInBackgroundMoveProcessingPool
value:       0
description: Total amount of memory (bytes) allocated in background processing pool (that is dedicated for backround moves). Note that this value may include a drift when the memory was allocated in a context of background processing pool and freed in other context or vice-versa. This happens naturally due to caches for tables indexes and doesn't indicate memory leaks.

Row 33:
───────
metric:      MemoryTrackingInBackgroundSchedulePool
value:       -4461308831
description: Total amount of memory (bytes) allocated in background schedule pool (that is dedicated for bookkeeping tasks of Replicated tables).

...

56 rows in set. Elapsed: 0.003 sec.
```

Server version: 20.8.2.3.
{
    auto lock = getLock();
    for (const SettingChange & change : changes)
        applySettingChange(change);
}
void Context::checkSettingsConstraints(const SettingChange & change) const
{
    if (auto settings_constraints = getSettingsConstraints())
        settings_constraints->check(settings, change);
}
void Context::checkSettingsConstraints(const SettingsChanges & changes) const
{
    if (auto settings_constraints = getSettingsConstraints())
        settings_constraints->check(settings, changes);
}
void Context::checkSettingsConstraints(SettingsChanges & changes) const
{
    if (auto settings_constraints = getSettingsConstraints())
        settings_constraints->check(settings, changes);
}
void Context::clampToSettingsConstraints(SettingsChanges & changes) const
{
    if (auto settings_constraints = getSettingsConstraints())
        settings_constraints->clamp(settings, changes);
}
std::shared_ptr<const SettingsConstraints> Context::getSettingsConstraints() const
{
    return getAccess()->getSettingsConstraints();
}
String Context::getCurrentDatabase() const