* fix(stats): Do not crash upon issuing `mem stats`
The reason for the crash is that we can't use a mutex while iterating
connections. It uses a non-Fiber `Await()`, and it also has a fiber
atomic guard.
Instead use the common trick of allocating per-thread data and aggregate
afterward.
* Use pool size
This PR introduces a test case for TLS with `ca_dir`. First, we
did not have any tests for this case. Second, using `ca_dir` requires
to call `c_rehash` on the directory before it is loaded by DF. We
did not have this use case anywhere and therefore we thought there was
a bug when we used `ca_dir` only to find out that we need to call
`c_rehash` on the directory before we load the certificates. Now,
both a test and a use case are properly documented
* add missing test for ca_dir
* use rehash to properly show how to load ca directories instead of
files
Then use the right version (hopefully) in the right places.
Specifically, this fixes a serialization bug, where we could send
malformed responses when using `UpperBoundSize()` to write array length.
Should allow track caches where Dragonfly is not responsive to I/O
due to big CPU tasks. Also, update the local grafana dashboard.
Signed-off-by: Roman Gershman <roman@dragonflydb.io>
This caused a UBSan warning to be printed in test `DflyEngineTest.Bug207`
```
/usr/include/c++/11/bits/stl_vector.h:1046:34: runtime error: reference binding to null pointer of type 'struct value_type'
```
The dashboard used `dragonfly_up` metric to boostrap itself
but this metric does not exist anymore. I replaced it with `dragonfly_version`
In addition, the exported format changed slightly because I used the
recent grafana version to export.
Signed-off-by: Roman Gershman <roman@dragonflydb.io>
Regression test sometimes fails because for a short period of time after `wait_available_async()` returns, the result of `ROLE` could still be different from `stable_sync`
[Failure example](https://github.com/dragonflydb/dragonfly/actions/runs/6726461923/job/18282759612#step:6:1863)
We change our state from `LOADING` to `ACTIVE` [here](d08d7f13b4/src/server/replica.cc (L426)), but then we change the sync state 2 times:
1. `!R_SYNCING` [here](d08d7f13b4/src/server/replica.cc (L427C28-L427C37))
2. And only later to `R_SYNC_OK` (meaning `stable_sync`) [here](d08d7f13b4/src/server/replica.cc (L221))
This is easy to reproduce by adding a sleep right after the set of state to `ACTIVE`, either before or after the flipping of `R_SYNCING` (with different returned states).
BTW without that added sleep I was not able to reproduce, having tried 1000s of times in various configurations.
We could change the order of things such that we first change `state_mask_` and only then switch state from `LOADING` to `ACTIVE` (which is probably the right thing to do), but that would require a subtle refactor, as we change these in a couple of places.
But we should keep in mind that this has no effect on users. So a simple sleep on the test side should fix this fairly well.
* fixes#1936
Eviction Implementation
This patch provides a very simple eviction implementation for the interface mentioned above. In my opinion, the eviction algorithm approximates an LRU policy given that normal buckets always store the most recently accessed data while stash buckets are holding less active data.
The algorithm first selects a small set of segments as eviction targets. Starting from the last slot of the last stash bucket in each of the segments, we walk backward to evict key-value pairs stored in each visited slot. The eviction stopped either when a target memory release goal or the max number of evicted key-value pairs is reached. Therefore, we can upper bound the eviction time through the following two parameters that can be set when DF starts. Note that these two parameters could be retrieved and changed by user through CONFIG GET and CONFIG SET commands.
---------
Signed-off-by: Yue Li <61070669+theyueli@users.noreply.github.com>
* chore: help users to fix a common mistake of setting quotes in the flagfile
Specifically, the confusion is often around the cron expression.
---------
Signed-off-by: Roman Gershman <roman@dragonflydb.io>
