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author | Binbin <binloveplay1314@qq.com> | 2022-10-09 13:18:34 +0800 |
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committer | GitHub <noreply@github.com> | 2022-10-09 08:18:34 +0300 |
commit | 35b3fbd90c2ad2c503c9e3d28bfbffff13099925 (patch) | |
tree | 8ca44f6572095f44f29fcddcefb8bdac3490b806 /src/server.h | |
parent | d2ad01ab3e24ca537efdd1fc6ff1ae2c657f4a51 (diff) | |
download | redis-35b3fbd90c2ad2c503c9e3d28bfbffff13099925.tar.gz |
Freeze time sampling during command execution, and scripts (#10300)
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`lookupKeyReadWithFlags` call in `getNodeByQuery` will get a outdated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.
Diffstat (limited to 'src/server.h')
-rw-r--r-- | src/server.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/server.h b/src/server.h index 74e4098db..2ec7dc7ea 100644 --- a/src/server.h +++ b/src/server.h @@ -1520,7 +1520,6 @@ struct redisServer { clientMemUsageBucket client_mem_usage_buckets[CLIENT_MEM_USAGE_BUCKETS]; rax *clients_timeout_table; /* Radix tree for blocked clients timeouts. */ - long fixed_time_expire; /* If > 0, expire keys against server.mstime. */ int in_nested_call; /* If > 0, in a nested call of a call */ rax *clients_index; /* Active clients dictionary by client ID. */ pause_type client_pause_type; /* True if clients are currently paused */ @@ -2420,7 +2419,8 @@ int moduleIsModuleCommand(void *module_handle, struct redisCommand *cmd); /* Utils */ long long ustime(void); -long long mstime(void); +mstime_t mstime(void); +mstime_t commandTimeSnapshot(void); void getRandomHexChars(char *p, size_t len); void getRandomBytes(unsigned char *p, size_t len); uint64_t crc64(uint64_t crc, const unsigned char *s, uint64_t l); |