Freeze time during execution of scripts and all other commands.
This means that a key is either expired or not, and doesn't change
state during a script execution. resolves#10182
This PR try to add a new `commandTimeSnapshot` function.
The function logic is extracted from `keyIsExpired`, but the related
calls to `fixed_time_expire` and `mstime()` are removed, see below.
In commands, we will avoid calling `mstime()` multiple times
and just use the one that sampled in call. The background is,
e.g. using `PEXPIRE 1` with valgrind sometimes result in the key
being deleted rather than expired. The reason is that both `PEXPIRE`
command and `checkAlreadyExpired` call `mstime()` separately.
There are other more important changes in this PR:
1. Eliminate `fixed_time_expire`, it is no longer needed.
When we want to sample time we should always use a time snapshot.
We will use `in_nested_call` instead to update the cached time in `call`.
2. Move the call for `updateCachedTime` from `serverCron` to `afterSleep`.
Now `commandTimeSnapshot` will always return the sample time, the
`lookupKeyReadWithFlags` call in `getNodeByQuery` will get a outdated
cached time (because `processCommand` is out of the `call` context).
We put the call to `updateCachedTime` in `aftersleep`.
3. Cache the time each time the module lock Redis.
Call `updateCachedTime` in `moduleGILAfterLock`, affecting `RM_ThreadSafeContextLock`
and `RM_ThreadSafeContextTryLock`
Currently the commandTimeSnapshot change affects the following TTL commands:
- SET EX / SET PX
- EXPIRE / PEXPIRE
- SETEX / PSETEX
- GETEX EX / GETEX PX
- TTL / PTTL
- EXPIRETIME / PEXPIRETIME
- RESTORE key TTL
And other commands just use the cached mstime (including TIME).
This is considered to be a breaking change since it can break a script
that uses a loop to wait for a key to expire.
35b3fbd90c