This adds Makefile/build-system support for USE_SYSTEMD=(yes|no|*). This
variable's value determines whether or not libsystemd will be linked at
build-time.
If USE_SYSTEMD is set to "yes", make will use PKG_CONFIG to check for
libsystemd's presence, and fail the build early if it isn't
installed/detected properly.
If USE_SYSTEM is set to "no", libsystemd will *not* be linked, even if
support for it is available on the system redis is being built on.
For any other value that USE_SYSTEM might assume (e.g. "auto"),
PKG_CONFIG will try to determine libsystemd's presence, and set up the
build process to link against it, if it was indicated as being
installed/available.
This approach has a number of repercussions of its own, most importantly
the following: If you build redis on a system that actually has systemd
support, but no libsystemd-dev package(s) installed, you'll end up
*without* support for systemd notification/status reporting support in
redis-server. This changes established runtime behaviour.
I'm not sure if the build system and/or the server binary should
indicate this. I'm also wondering if not actually having
systemd-notify-support, but requesting it via the server's config,
should result in a fatal error now.
Instead of replicating a subset of libsystemd's sd_notify(3) internally,
use the dynamic library provided by systemd to communicate with the
service manager.
When systemd supervision was auto-detected or configured, communicate
the actual server status (i.e. "Loading dataset", "Waiting for
master<->replica sync") to systemd, instead of declaring readiness right
after initializing the server process.
Reduce default minimum effort, so that when fragmentation is just detected,
the impact on the latency will be minor.
Reduce the default maximum effort, mainly to prevent a case were a sudden
massive deletions, won't trigger an aggressive defrag that will cause latency.
When activedefrag is disabled mid-run, reset the 'running' info field, and
clear the scan cursor, so that when it'll be re-enabled, a new fresh scan will
start.
Clearing the 'running' variable is important since lowering the defragger
tunables mid-scan won't help, the defragger only considers new threshold when
a new scan starts, and during a scan it can only become more aggressive,
(when more severe fragmentation is detected), it'll never go less aggressive.
So by temporarily disabling activedefrag, one can lower th the tunables.
Removing the experimantal warning.
- the API name was odd, separated to two apis one for LRU and one for LFU
- the LRU idle time was in 1 second resolution, which might be ok for RDB
and RESTORE, but i think modules may need higher resolution
- adding tests for LFU and for handling maxmemory policy mismatch
One problem with the solution proposed so far in #6537 is that key
lookups outside a command execution via call(), still used a cached
time. The cached time needed to be refreshed in multiple places,
especially because of modules callbacks from timers, cluster bus, and
thread safe contexts, that may use RM_Open().
In order to avoid this problem, this commit introduces the ability to
detect if we are inside call(): this way we can use the reference fixed
time only when we are in the context of a command execution or Lua
script, but for the asynchronous lookups, we can still use mstime() to
get a fresh time reference.
After the thread in #6537 and thanks to the suggestions received, this
commit updates the original patch in order to:
1. Solve the problem of updating the time in multiple places by updating
it in call().
2. Avoid introducing a new field but use our cached time.
This required some minor refactoring to the function updating the time,
and the introduction of a new cached time in microseconds in order to
use less gettimeofday() calls.
Calling lookupKey*() many times to search a key in one command
may get different result.
That's because lookupKey*() calls expireIfNeeded(), and delete
the key when reach the expire time. So we can get an robj before
the expire time, but a NULL after the expire time.
The worst is that may lead to Redis crash, for example
`RPOPLPUSH foo foo` the first time we get a list form `foo` and
hold the pointer, but when we get `foo` again it's expired and
deleted. Now we hold a freed memory, when execute rpoplpushHandlePush()
redis crash.
To fix it, we can refactor the judgment about whether a key is expired,
using the same basetime `server.cmd_start_mstime` instead of calling
mstime() everytime.
- Add RM_GetServerInfo and friends
- Add auto memory for new opaque struct
- Add tests for new APIs
other minor fixes:
- add const in various char pointers
- requested_section in modulesCollectInfo was actually not sds but char*
- extract new string2d out of getDoubleFromObject for code reuse
Add module API for
Using the is_key_ready() callback plus the reply callback later, creates
different issues AFAIK:
1. More complex API.
2. We need to call the reply callback() ASAP if the is_key_ready()
interface returned success, however the internals do not work in that
way, so when the reply callback is called the setup could be different.
To fix that, there is to break the current design that handles the
unblocked clients asyncrhonously, and run the list ASAP.
* replication hooks: role change, master link status, replica online/offline
* persistence hooks: saving, loading, loading progress
* misc hooks: cron loop, shutdown, module loaded/unloaded
* change the way hooks test work, and add tests for all of the above
startLoading() now gets flag indicating what is loaded.
stopLoading() now gets an indication of success or failure.
adding startSaving() and stopSaving() with similar args and role.
Some commands would want to open a key without touching it's LRU/LFU
similarly to the OBJECT or DEBUG command do.
Other commands may want to implement logic similar to what RESTORE
does (and in the future MIGRATE) and get/set the LRU or LFU.
Note: This change moves our assembly code to use the GNU Assembler because NASM seems to be incapable of emitting the necessary debug information for callstack unwinding to work.
Former-commit-id: 600fc241cfe79b9b32ac6010c6ea0c66747f0f15
