* The corrupt dump fuzzer found a division by zero.
* in some cases the random fields from the HRANDFIELD tests produced
fields with newlines and other special chars (due to \ char), this caused
the TCL tests to see a bulk response that has a newline in it and add {}
around it, later it can think this is a nested list. in fact the `alpha` random
string generator isn't using spaces and newlines, so it should not use `\`
either.
* The corrupt dump fuzzer found a division by zero.
* in some cases the random fields from the HRANDFIELD tests produced
fields with newlines and other special chars (due to \ char), this caused
the TCL tests to see a bulk response that has a newline in it and add {}
around it, later it can think this is a nested list. in fact the `alpha` random
string generator isn't using spaces and newlines, so it should not use `\`
either.
This commit enables tracking time of the background tasks and on replies,
opening the door for properly tracking commands that rely on blocking / background
work via the slowlog, latency history, and commandstats.
Some notes:
- The time spent blocked waiting for key changes, or blocked on synchronous
replication is not accounted for.
- **This commit does not affect latency tracking of commands that are non-blocking
or do not have background work.** ( meaning that it all stays the same with exception to
`BZPOPMIN`,`BZPOPMAX`,`BRPOP`,`BLPOP`, etc... and module's commands that rely
on background threads ).
- Specifically for latency history command we've added a new event class named
`command-unblocking` that will enable latency monitoring on commands that spawn
background threads to do the work.
- For blocking commands we're now considering the total time of a command as the
time spent on call() + the time spent on replying when unblocked.
- For Modules commands that rely on background threads we're now considering the
total time of a command as the time spent on call (main thread) + the time spent on
the background thread ( if marked within `RedisModule_MeasureTimeStart()` and
`RedisModule_MeasureTimeEnd()` ) + the time spent on replying (main thread)
To test for this feature we've added a `unit/moduleapi/blockonbackground` test that relies on
a module that blocks the client and sleeps on the background for a given time.
- check blocked command that uses RedisModule_MeasureTimeStart() is tracking background time
- check blocked command that uses RedisModule_MeasureTimeStart() is tracking background time even in timeout
- check blocked command with multiple calls RedisModule_MeasureTimeStart() is tracking the total background time
- check blocked command without calling RedisModule_MeasureTimeStart() is not reporting background time
This commit enables tracking time of the background tasks and on replies,
opening the door for properly tracking commands that rely on blocking / background
work via the slowlog, latency history, and commandstats.
Some notes:
- The time spent blocked waiting for key changes, or blocked on synchronous
replication is not accounted for.
- **This commit does not affect latency tracking of commands that are non-blocking
or do not have background work.** ( meaning that it all stays the same with exception to
`BZPOPMIN`,`BZPOPMAX`,`BRPOP`,`BLPOP`, etc... and module's commands that rely
on background threads ).
- Specifically for latency history command we've added a new event class named
`command-unblocking` that will enable latency monitoring on commands that spawn
background threads to do the work.
- For blocking commands we're now considering the total time of a command as the
time spent on call() + the time spent on replying when unblocked.
- For Modules commands that rely on background threads we're now considering the
total time of a command as the time spent on call (main thread) + the time spent on
the background thread ( if marked within `RedisModule_MeasureTimeStart()` and
`RedisModule_MeasureTimeEnd()` ) + the time spent on replying (main thread)
To test for this feature we've added a `unit/moduleapi/blockonbackground` test that relies on
a module that blocks the client and sleeps on the background for a given time.
- check blocked command that uses RedisModule_MeasureTimeStart() is tracking background time
- check blocked command that uses RedisModule_MeasureTimeStart() is tracking background time even in timeout
- check blocked command with multiple calls RedisModule_MeasureTimeStart() is tracking the total background time
- check blocked command without calling RedisModule_MeasureTimeStart() is not reporting background time
New commands:
`HRANDFIELD [<count> [WITHVALUES]]`
`ZRANDMEMBER [<count> [WITHSCORES]]`
Algorithms are similar to the one in SRANDMEMBER.
Both return a simple bulk response when no arguments are given, and an array otherwise.
In case values/scores are requested, RESP2 returns a long array, and RESP3 a nested array.
note: in all 3 commands, the only option that also provides random order is the one with negative count.
Changes to SRANDMEMBER
* Optimization when count is 1, we can use the more efficient algorithm of non-unique random
* optimization: work with sds strings rather than robj
Other changes:
* zzlGetScore: when zset needs to convert string to double, we use safer memcpy (in
case the buffer is too small)
* Solve a "bug" in SRANDMEMBER test: it intended to test a positive count (case 3 or
case 4) and by accident used a negative count
Co-authored-by: xinluton <xinluton@qq.com>
Co-authored-by: Oran Agra <oran@redislabs.com>
New commands:
`HRANDFIELD [<count> [WITHVALUES]]`
`ZRANDMEMBER [<count> [WITHSCORES]]`
Algorithms are similar to the one in SRANDMEMBER.
Both return a simple bulk response when no arguments are given, and an array otherwise.
In case values/scores are requested, RESP2 returns a long array, and RESP3 a nested array.
note: in all 3 commands, the only option that also provides random order is the one with negative count.
Changes to SRANDMEMBER
* Optimization when count is 1, we can use the more efficient algorithm of non-unique random
* optimization: work with sds strings rather than robj
Other changes:
* zzlGetScore: when zset needs to convert string to double, we use safer memcpy (in
case the buffer is too small)
* Solve a "bug" in SRANDMEMBER test: it intended to test a positive count (case 3 or
case 4) and by accident used a negative count
Co-authored-by: xinluton <xinluton@qq.com>
Co-authored-by: Oran Agra <oran@redislabs.com>
The key point is how to recover from last AOF write error, for example:
1. start redis with appendonly yes, and append some write commands
2. short write or something else error happen, `server.aof_last_write_status` changed to `C_ERR`, now redis doesn't accept write commands
3. execute `CONFIG SET appendonly no` to avoid the above problem, now redis can accept write commands again
4. disk error resolved, and execute `CONFIG SET appendonly yes` to reopen AOF, but `server.aof_last_write_status` cannot be changed to `C_OK` (if background aof rewrite run less then 1 second, it will free `server.aof_buf` and then serverCron cannot fix `aof_last_write_status`), then redis cannot accept write commands forever.
This PR use a simple way to fix it:
1. just free `server.aof_buf` when stop appendonly to save memory, if error happens in `flushAppendOnlyFile(1)`, the `server.aof_buf` may contains some data which has not be written to aof, I think we can ignore it because we turn off the appendonly.
2. reset fsync status after stop appendonly and call `flushAppendOnlyFile` only when `aof_state` is ON
3. reset `server.last_write_status` when reopen aof to accept write commands
The key point is how to recover from last AOF write error, for example:
1. start redis with appendonly yes, and append some write commands
2. short write or something else error happen, `server.aof_last_write_status` changed to `C_ERR`, now redis doesn't accept write commands
3. execute `CONFIG SET appendonly no` to avoid the above problem, now redis can accept write commands again
4. disk error resolved, and execute `CONFIG SET appendonly yes` to reopen AOF, but `server.aof_last_write_status` cannot be changed to `C_OK` (if background aof rewrite run less then 1 second, it will free `server.aof_buf` and then serverCron cannot fix `aof_last_write_status`), then redis cannot accept write commands forever.
This PR use a simple way to fix it:
1. just free `server.aof_buf` when stop appendonly to save memory, if error happens in `flushAppendOnlyFile(1)`, the `server.aof_buf` may contains some data which has not be written to aof, I think we can ignore it because we turn off the appendonly.
2. reset fsync status after stop appendonly and call `flushAppendOnlyFile` only when `aof_state` is ON
3. reset `server.last_write_status` when reopen aof to accept write commands
