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Fix#784
Prior to the change, `CLUSTER SHARDS` command processing might pick a
failed primary node which won't have the slot coverage information and
the slots `output` in turn would be empty. This change finds an
appropriate node which has the slot coverage information served by a
given shard and correctly displays it as part of `CLUSTER SHARDS`
output.
Before:
```
1) 1) "slots"
2) (empty array)
3) "nodes"
4) 1) 1) "id"
2) "2936f22a490095a0a851b7956b0a88f2b67a5d44"
...
9) "role"
10) "master"
...
13) "health"
14) "fail"
```
After:
```
1) 1) "slots"
2) 1) 0
2) 5461
3) "nodes"
4) 1) 1) "id"
2) "2936f22a490095a0a851b7956b0a88f2b67a5d44"
...
9) "role"
10) "master"
...
13) "health"
14) "fail"
```
---------
Signed-off-by: Harkrishn Patro <harkrisp@amazon.com>
### IO-Threads Work Offloading
This PR is the 2nd of 3 PRs intended to achieve the goal of 1M requests
per second.
(1st PR: https://github.com/valkey-io/valkey/pull/758)
This PR offloads additional work to the I/O threads, beyond the current
read-parse/write operations, to better utilize the I/O threads and
reduce the load on the main thread.
It contains the following 3 commits:
### Poll Offload
Currently, the main thread is responsible for executing the poll-wait
system call, while the IO threads wait for tasks from the main thread.
The poll-wait operation is expensive and can consume up to 30% of the
main thread's time. We could have let the IO threads do the poll-wait by
themselves, with each thread listening to some of the clients and
notifying the main thread when a client's command is ready to execute.
However, the current approach, where the main thread listens for events
from the network, has several benefits. The main thread remains in
charge, allowing it to know the state of each client
(idle/read/write/close) at any given time. Additionally, it makes the
threads flexible, enabling us to drain an IO thread's job queue and stop
a thread when the load is light without modifying the event loop and
moving its clients to a different IO thread. Furthermore, with this
approach, the IO threads don't need to wait for both messages from the
network and from the main thread instead, the threads wait only for
tasks from the main thread.
To enjoy the benefits of both the main thread remaining in charge and
the poll being offloaded, we propose offloading the poll-wait as a
single-time, non-blocking job to one of the IO threads. The IO thread
will perform a poll-wait non-blocking call while the main thread
processes the client commands. Later, in `aeProcessEvents`, instead of
sleeping on the poll, we check for the IO thread's poll-wait results.
The poll-wait will be offloaded in `beforeSleep` only when there are
ready events for the main thread to process. If no events are pending,
the main thread will revert to the current behavior and sleep on the
poll by itself.
**Implementation Details**
A new call back `custompoll` was added to the `aeEventLoop` when not set
to `NULL` the ae will call the `custompoll` callback instead of the
`aeApiPoll`.
When the poll is offloaded we will set the `custompoll` to
`getIOThreadPollResults` and send a poll-job to the thread. the thread
will take a mutex, call a non-blocking (with timeout 0) to `aePoll`
which will populate the fired events array. the IO thread will set the
`server.io_fired_events` to the number of the returning `numevents`,
later the main-thread in `custompoll` will return the
`server.io_fired_events` and will set the `customPoll` back to `NULL`.
To ensure thread safety when accessing server.el, all functions that
modify the eventloop events were wrapped with a mutex to ensure mutual
exclusion when modifying the events.
### Command Lookup Offload
As the IO thread parses the command from the client's Querybuf, it can
perform a command lookup in the commands dictionary, which can consume
up to ~5% of the main-thread runtime.
**Implementation details**
The IO thread will store the looked-up command in the client's new field
`io_parsed_cmd` field. We can't use `c->cmd` for that since we use
`c->cmd `to check if a command was reprocessed or not.
To ensure thread safety when accessing the command dictionary, we make
sure the main thread isn't changing the dictionary while IO threads are
accessing it. This is accomplished by introducing a new flag called
`no_incremental_rehash` for the `dictType` commands. When performing
`dictResize`, we will rehash the entire dictionary in place rather than
deferring the process.
### Free Offload
Since the command arguments are allocated by the I/O thread, it would be
beneficial if they were also freed by the same thread. If the main
thread frees objects allocated by the I/O thread, two issues arise:
1. During the freeing process, the main thread needs to access the SDS
pointed to by the object to get its length.
2. With Jemalloc, each thread manages thread local pool (`tcache`) of
buffers for quick reallocation without accessing the arena. If the main
thread constantly frees objects allocated by other threads, those
threads will have to frequently access the shared arena to obtain new
memory allocations
**Implementation Details**
When freeing the client's argv, we will send the argv array to the
thread that allocated it. The thread will be identified by the client
ID. When freeing an object during `dbOverwrite`, we will offload the
object free as well. We will extend this to offload the free during
`dbDelete` in a future PR, as its effects on defrag/memory evictions
need to be studied.
---------
Signed-off-by: Uri Yagelnik <uriy@amazon.com>
Primary side: Remove read handler upon RDB connection close.
At this stage we do not expect any writed form that connection
so it should be safe to remove the read handler. Otherwise the
read handler will keep printing the `Client closed connection`
logs, see handleReadResult.
Signed-off-by: naglera <anagler123@gmail.com>
server.rdb_child_exit_pipe is init in !dual_channel block,
so the call here would be close(-1) in !dual_channel way.
It will also generate a warning in valgrind:
Warning: invalid file descriptor -1 in syscall close()
Introduced in #60.
Signed-off-by: Binbin <binloveplay1314@qq.com>
After #60, the CI report this warning:
```
rdb.c: In function 'rdbSaveToReplicasSockets':
rdb.c:3661:28: error: 'safe_to_exit_pipe' may be used uninitialized [-Werror=maybe-uninitialized]
3661 | if (!dual_channel) close(safe_to_exit_pipe);
| ^~~~~~~~~~~~~~~~~~~~~~~~
rdb.c:3512:37: note: 'safe_to_exit_pipe' was declared here
3512 | int pipefds[2], rdb_pipe_write, safe_to_exit_pipe;
| ^~~~~~~~~~~~~~~~~
rdb.c:3654:17: error: 'rdb_pipe_write' may be used uninitialized [-Werror=maybe-uninitialized]
3654 | close(rdb_pipe_write); /* close write in parent so that it can detect the close on the child. */
| ^~~~~~~~~~~~~~~~~~~~~
rdb.c:3512:21: note: 'rdb_pipe_write' was declared here
3512 | int pipefds[2], rdb_pipe_write, safe_to_exit_pipe;
| ^~~~~~~~~~~~~~
cc1: all warnings being treated as errors
```
Signed-off-by: Binbin <binloveplay1314@qq.com>
In this PR we introduce the main benefit of dual channel replication by
continuously steaming the COB (client output buffers) in parallel to the
RDB and thus keeping the primary's side COB small AND accelerating the
overall sync process. By streaming the replication data to the replica
during the full sync, we reduce
1. Memory load from the primary's node.
2. CPU load from the primary's main process. [Latest performance
tests](#data)
## Motivation
* Reduce primary memory load. We do that by moving the COB tracking to
the replica side. This also decrease the chance for COB overruns. Note
that primary's input buffer limits at the replica side are less
restricted then primary's COB as the replica plays less critical part in
the replication group. While increasing the primary’s COB may end up
with primary reaching swap and clients suffering, at replica side we’re
more at ease with it. Larger COB means better chance to sync
successfully.
* Reduce primary main process CPU load. By opening a new, dedicated
connection for the RDB transfer, child processes can have direct access
to the new connection. Due to TLS connection restrictions, this was not
possible using one main connection. We eliminate the need for the child
process to use the primary's child-proc -> main-proc pipeline, thus
freeing up the main process to process clients queries.
## Dual Channel Replication high level interface design
- Dual channel replication begins when the replica sends a `REPLCONF
CAPA DUALCHANNEL` to the primary during initial
handshake. This is used to state that the replica is capable of dual
channel sync and that this is the replica's main channel, which is not
used for snapshot transfer.
- When replica lacks sufficient data for PSYNC, the primary will send
`-FULLSYNCNEEDED` response instead
of RDB data. As a next step, the replica creates a new connection
(rdb-channel) and configures it against
the primary with the appropriate capabilities and requirements. The
replica then requests a sync
using the RDB channel.
- Prior to forking, the primary sends the replica the snapshot's end
repl-offset, and attaches the replica
to the replication backlog to keep repl data until the replica requests
psync. The replica uses the main
channel to request a PSYNC starting at the snapshot end offset.
- The primary main threads sends incremental changes via the main
channel, while the bgsave process
sends the RDB directly to the replica via the rdb-channel. As for the
replica, the incremental
changes are stored on a local buffer, while the RDB is loaded into
memory.
- Once the replica completes loading the rdb, it drops the
rdb-connection and streams the accumulated incremental
changes into memory. Repl steady state continues normally.
## New replica state machine
## Data <a name="data"></a>
## Explanation
These graphs demonstrate performance improvements during full sync
sessions using rdb-channel + streaming rdb directly from the background
process to the replica.
First graph- with at most 50 clients and light weight commands, we saw
5%-7.5% improvement in write latency during sync session.
Two graphs below- full sync was tested during heavy read commands from
the primary (such as sdiff, sunion on large sets). In that case, the
child process writes to the replica without sharing CPU with the loaded
main process. As a result, this not only improves client response time,
but may also shorten sync time by about 50%. The shorter sync time
results in less memory being used to store replication diffs (>60% in
some of the tested cases).
## Test setup
Both primary and replica in the performance tests ran on the same
machine. RDB size in all tests is 3.7gb. I generated write load using
valkey-benchmark ` ./valkey-benchmark -r 100000 -n 6000000 lpush my_list
__rand_int__`.
---------
Signed-off-by: naglera <anagler123@gmail.com>
Signed-off-by: naglera <58042354+naglera@users.noreply.github.com>
Co-authored-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
Co-authored-by: Ping Xie <pingxie@outlook.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
Fixes a regression introduced in PR #445, which allowed a message from a
replica
to update the slot ownership of its primary. The regression results in a
`replicaof` cycle, causing server crashes due to the cycle detection
assert. The
fix restores the previous behavior where only primary senders can
trigger
`clusterUpdateSlotsConfigWith`.
Additional changes:
* Handling of primaries without slots is obsoleted by new handling of
when a
sender that was a replica announces that it is now a primary.
* Replication loop detection code is unchanged but shifted downwards.
* Some variables are renamed for better readability and some are
introduced to
avoid repeated memcmp() calls.
Fixes#753.
---------
Signed-off-by: Ping Xie <pingxie@google.com>
Update sentinel.conf config parameter,
From:
SENTINEL master-reboot-down-after-period mymaster 0
To:
SENTINEL primary-reboot-down-after-period myprimary 0
But we still keep the backward compatibility, clients could use SENTINEL
master-reboot-down-after-period mymaster 0 OR
SENTINEL primary-reboot-down-after-period myprimary 0
---------
Signed-off-by: hwware <wen.hui.ware@gmail.com>
Adds an option to build RDMA support as a module:
make BUILD_RDMA=module
To start valkey-server with RDMA, use a command line like the following:
./src/valkey-server --loadmodule src/valkey-rdma.so \
port=6379 bind=xx.xx.xx.xx
* Implement server side of connection module only, this means we can
*NOT*
compile RDMA support as built-in.
* Add necessary information in README.md
* Support 'CONFIG SET/GET', for example, 'CONFIG Set rdma.port 6380',
then
check this by 'rdma res show cm_id' and valkey-cli (with RDMA support,
but not implemented in this patch).
* The full listeners show like:
listener0:name=tcp,bind=*,bind=-::*,port=6379
listener1:name=unix,bind=/var/run/valkey.sock
listener2:name=rdma,bind=xx.xx.xx.xx,bind=yy.yy.yy.yy,port=6379
listener3:name=tls,bind=*,bind=-::*,port=16379
Because the lack of RDMA support from TCL, use a simple C program to
test
Valkey Over RDMA (under tests/rdma/). This is a quite raw version with
basic
library dependence: libpthread, libibverbs, librdmacm. Run using the
script:
./runtest-rdma [ OPTIONS ]
To run RDMA in GitHub actions, a kernel module RXE for emulated soft
RDMA, needs
to be installed. The kernel module source code is fetched a repo
containing only
the RXE kernel driver from the Linux kernel, but stored in an separate
repo to
avoid cloning the whole Linux kernel repo.
----
Since 2021/06, I created a
[PR](https://github.com/redis/redis/pull/9161) for *Redis Over RDMA*
proposal. Then I did some work to [fully abstract connection and make
TLS dynamically loadable](https://github.com/redis/redis/pull/9320), a
new connection type could be built into Redis statically, or a separated
shared library(loaded by Redis on startup) since Redis 7.2.0.
Base on the new connection framework, I created a new
[PR](https://github.com/redis/redis/pull/11182), some
guys(@xiezhq-hermann @zhangyiming1201 @JSpewock @uvletter @FujiZ)
noticed, played and tested this PR. However, because of the lack of time
and knowledge from the maintainers, this PR has been pending about 2
years.
Related doc: [Introduce *Valkey Over RDMA*
specification](https://github.com/valkey-io/valkey-doc/pull/123). (same
as Redis, and this should be same)
Changes in this PR:
- implement *Valkey Over RDMA*. (compact the Valkey style)
Finally, if this feature is considered to merge, I volunteer to maintain
it.
---------
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Implementing the change proposed here:
https://github.com/valkey-io/valkey/issues/487
In this PR, we prevent tracking new custom error messages (e.g. LUA) if
the number of error messages (in the errors RAX) is greater than 128.
Instead, we will track any additional custom error prefix in a new
counter: `errorstat_ERRORSTATS_OVERFLOW ` and if any non-custom flagged
errors (e.g. MOVED / CLUSTERDOWN) occur, they will continue to be
tracked as usual.
This will address the issue of spammed error messages / memory usage of
the errors RAX. Additionally, we will not have to execute `CONFIG
RESETSTAT` to restore error stats functionality because normal error
messages continue to be tracked.
Example:
```
# Errorstats
.
.
.
errorstat_127:count=2
errorstat_128:count=2
errorstat_ERR:count=1
errorstat_ERRORSTATS_OVERFLOW:count=2
```
---------
Signed-off-by: Karthik Subbarao <karthikrs2021@gmail.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Allows cluster admins to configure the blacklist TTL as needed to allow
sufficient time for `CLUSTER FORGET` to be executed on every node in the
cluster.
Config name `cluster-blacklist-ttl`; unit seconds; deault 60.
---------
Signed-off-by: Brennan Cathcart <brennancathcart@gmail.com>
Normally we can create a test cluster directly in the directory
using `./utils/create-cluster/create-cluster`, which would keep
the test files under `./` and messed up the git.
Signed-off-by: Binbin <binloveplay1314@qq.com>
Inputing a negative number equivalent to --loop, and inputing a
number greater than or equal to 0 will cause the tests to be run
one more time.
Signed-off-by: Binbin <binloveplay1314@qq.com>
The test fails because, in external, another test may have
enabled appendonly, causing acklocal to return 1.
We can add a CONFIG SET to disable the appendonly, but this
is not safe too unless we use multi. The test does not actually
rely on appendonly, so we can just * it.
Fixes#770.
Signed-off-by: Binbin <binloveplay1314@qq.com>
New configs:
* `cluster-announce-client-ipv4`
* `cluster-announce-client-ipv6`
New module API function:
* `ValkeyModule_GetClusterNodeInfoForClient`, takes a client id and is
otherwise just like its non-ForClient cousin.
If configured, one of these IP addresses are reported to each client in
CLUSTER SLOTS, CLUSTER SHARDS, CLUSTER NODES and redirects, replacing
the IP (`custer-announce-ip` or the auto-detected IP) of each node.
Which one is reported to the client depends on whether the client is
connected over IPv4 or IPv6.
Benefits:
* This allows clients using IPv4 to get the IPv4 addresses of all
cluster nodes and IPv6 clients to get the IPv6 clients.
* This allows the IPs visible to clients to be different to the IPs used
between the cluster nodes due to NAT'ing.
The information is propagated in the cluster bus using new Ping
extensions. (Old nodes without this feature ignore unknown Ping
extensions.)
This adds another dimension to CLUSTER SLOTS reply. It now depends on
the client's use of TLS, the IP address family and RESP version.
Refactoring: The cached connection type definition is moved from
connection.h (it actually has nothing to do with the connection
abstraction) to server.h and is changed to a bitmap, with one bit for
each of TLS, IPv6 and RESP3.
Fixes#337
---------
Signed-off-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
I noticed in #738 that we don't properly check ULong config boundaries
and made the change there. I'm pulling out that particular commit into
this PR since we don't know if we want to merge the configurable cluster
blacklist TTL yet.
---------
Signed-off-by: Brennan Cathcart <brennancathcart@gmail.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
Test case "EVAL - Scripts do not block on waitaof" observed to fail in
e.g.
https://github.com/valkey-io/valkey/actions/runs/9860131487/job/27233756421?pr=688
It can happen that the local AOF has been written and 1 is returned here
where 0 is expected. Writing a key inside the EVAL script makes sure
there's no time to write the AOF.
Signed-off-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
for kqueue:
EV_DELETE fails if the specified fd is not associated with the kqfd. If
EVFILT_WRITE is associated but EVFILT_READ is not, then calling
aeApiDelEvent with mask = -1 or `(AE_READABLE|AE_WRITABLE)` will
cause the kevent() to fail with errno = 2(No such file or directory) and
EVFILT_WRITE not dissociated. So we need to calculate the actual mask
to be removed, instead of passing in whatever user provides.
for evport:
The comment clearly states that aeApiDelEvent "rely on the fact that our
caller has already updated the mask in the eventLoop".
for epoll:
There's no need to calculate the "actual mask" twice, once in
`aeDeleteFileEvent` and another in `aeApiDelEvent`, let's just use the
mask recorded in the eventLoop.
Fixes#715
Signed-off-by: wkgcass <wkgcass@hotmail.com>
Co-authored-by: Andy Pan <i@andypan.me>
Co-authored-by: Binbin <binloveplay1314@qq.com>
This PR is 1 of 3 PRs intended to achieve the goal of 1 million requests
per second, as detailed by [dan touitou](https://github.com/touitou-dan)
in https://github.com/valkey-io/valkey/issues/22. This PR modifies the
IO threads to be fully asynchronous, which is a first and necessary step
to allow more work offloading and better utilization of the IO threads.
### Current IO threads state:
Valkey IO threads were introduced in Redis 6.0 to allow better
utilization of multi-core machines. Before this, Redis was
single-threaded and could only use one CPU core for network and command
processing. The introduction of IO threads helps in offloading the IO
operations to multiple threads.
**Current IO Threads flow:**
1. Initialization: When Redis starts, it initializes a specified number
of IO threads. These threads are in addition to the main thread, each
thread starts with an empty list, the main thread will populate that
list in each event-loop with pending-read-clients or
pending-write-clients.
2. Read Phase: The main thread accepts incoming connections and reads
requests from clients. The reading of requests are offloaded to IO
threads. The main thread puts the clients ready-to-read in a list and
set the global io_threads_op to IO_THREADS_OP_READ, the IO threads pick
the clients up, perform the read operation and parse the first incoming
command.
3. Command Processing: After reading the requests, command processing is
still single-threaded and handled by the main thread.
4. Write Phase: Similar to the read phase, the write phase is also be
offloaded to IO threads. The main thread prepares the response in the
clients’ output buffer then the main thread puts the client in the list,
and sets the global io_threads_op to the IO_THREADS_OP_WRITE. The IO
threads then pick the clients up and perform the write operation to send
the responses back to clients.
5. Synchronization: The main-thread communicate with the threads on how
many jobs left per each thread with atomic counter. The main-thread
doesn’t access the clients while being handled by the IO threads.
**Issues with current implementation:**
* Underutilized Cores: The current implementation of IO-threads leads to
the underutilization of CPU cores.
* The main thread remains responsible for a significant portion of
IO-related tasks that could be offloaded to IO-threads.
* When the main-thread is processing client’s commands, the IO threads
are idle for a considerable amount of time.
* Notably, the main thread's performance during the IO-related tasks is
constrained by the speed of the slowest IO-thread.
* Limited Offloading: Currently, Since the Main-threads waits
synchronously for the IO threads, the Threads perform only read-parse,
and write operations, with parsing done only for the first command. If
the threads can do work asynchronously we may offload more work to the
threads reducing the load from the main-thread.
* TLS: Currently, we don't support IO threads with TLS (where offloading
IO would be more beneficial) since TLS read/write operations are not
thread-safe with the current implementation.
### Suggested change
Non-blocking main thread - The main thread and IO threads will operate
in parallel to maximize efficiency. The main thread will not be blocked
by IO operations. It will continue to process commands independently of
the IO thread's activities.
**Implementation details**
**Inter-thread communication.**
* We use a static, lock-free ring buffer of fixed size (2048 jobs) for
the main thread to send jobs and for the IO to receive them. If the ring
buffer fills up, the main thread will handle the task itself, acting as
back pressure (in case IO operations are more expensive than command
processing). A static ring buffer is a better candidate than a dynamic
job queue as it eliminates the need for allocation/freeing per job.
* An IO job will be in the format: ` [void* function-call-back | void
*data] `where data is either a client to read/write from and the
function-ptr is the function to be called with the data for example
readQueryFromClient using this format we can use it later to offload
other types of works to the IO threads.
* The Ring buffer is one way from the main-thread to the IO thread, Upon
read/write event the main thread will send a read/write job then in
before sleep it will iterate over the pending read/write clients to
checking for each client if the IO threads has already finished handling
it. The IO thread signals it has finished handling a client read/write
by toggling an atomic flag read_state / write_state on the client
struct.
**Thread Safety**
As suggested in this solution, the IO threads are reading from and
writing to the clients' buffers while the main thread may access those
clients.
We must ensure no race conditions or unsafe access occurs while keeping
the Valkey code simple and lock free.
Minimal Action in the IO Threads
The main change is to limit the IO thread operations to the bare
minimum. The IO thread will access only the client's struct and only the
necessary fields in this struct.
The IO threads will be responsible for the following:
* Read Operation: The IO thread will only read and parse a single
command. It will not update the server stats, handle read errors, or
parsing errors. These tasks will be taken care of by the main thread.
* Write Operation: The IO thread will only write the available data. It
will not free the client's replies, handle write errors, or update the
server statistics.
To achieve this without code duplication, the read/write code has been
refactored into smaller, independent components:
* Functions that perform only the read/parse/write calls.
* Functions that handle the read/parse/write results.
This refactor accounts for the majority of the modifications in this PR.
**Client Struct Safe Access**
As we ensure that the IO threads access memory only within the client
struct, we need to ensure thread safety only for the client's struct's
shared fields.
* Query Buffer
* Command parsing - The main thread will not try to parse a command from
the query buffer when a client is offloaded to the IO thread.
* Client's memory checks in client-cron - The main thread will not
access the client query buffer if it is offloaded and will handle the
querybuf grow/shrink when the client is back.
* CLIENT LIST command - The main thread will busy-wait for the IO thread
to finish handling the client, falling back to the current behavior
where the main thread waits for the IO thread to finish their
processing.
* Output Buffer
* The IO thread will not change the client's bufpos and won't free the
client's reply lists. These actions will be done by the main thread on
the client's return from the IO thread.
* bufpos / block→used: As the main thread may change the bufpos, the
reply-block→used, or add/delete blocks to the reply list while the IO
thread writes, we add two fields to the client struct: io_last_bufpos
and io_last_reply_block. The IO thread will write until the
io_last_bufpos, which was set by the main-thread before sending the
client to the IO thread. If more data has been added to the cob in
between, it will be written in the next write-job. In addition, the main
thread will not trim or merge reply blocks while the client is
offloaded.
* Parsing Fields
* Client's cmd, argc, argv, reqtype, etc., are set during parsing.
* The main thread will indicate to the IO thread not to parse a cmd if
the client is not reset. In this case, the IO thread will only read from
the network and won't attempt to parse a new command.
* The main thread won't access the c→cmd/c→argv in the CLIENT LIST
command as stated before it will busy wait for the IO threads.
* Client Flags
* c→flags, which may be changed by the main thread in multiple places,
won't be accessed by the IO thread. Instead, the main thread will set
the c→io_flags with the information necessary for the IO thread to know
the client's state.
* Client Close
* On freeClient, the main thread will busy wait for the IO thread to
finish processing the client's read/write before proceeding to free the
client.
* Client's Memory Limits
* The IO thread won't handle the qb/cob limits. In case a client crosses
the qb limit, the IO thread will stop reading for it, letting the main
thread know that the client crossed the limit.
**TLS**
TLS is currently not supported with IO threads for the following
reasons:
1. Pending reads - If SSL has pending data that has already been read
from the socket, there is a risk of not calling the read handler again.
To handle this, a list is used to hold the pending clients. With IO
threads, multiple threads can access the list concurrently.
2. Event loop modification - Currently, the TLS code
registers/unregisters the file descriptor from the event loop depending
on the read/write results. With IO threads, multiple threads can modify
the event loop struct simultaneously.
3. The same client can be sent to 2 different threads concurrently
(https://github.com/redis/redis/issues/12540).
Those issues were handled in the current PR:
1. The IO thread only performs the read operation. The main thread will
check for pending reads after the client returns from the IO thread and
will be the only one to access the pending list.
2. The registering/unregistering of events will be similarly postponed
and handled by the main thread only.
3. Each client is being sent to the same dedicated thread (c→id %
num_of_threads).
**Sending Replies Immediately with IO threads.**
Currently, after processing a command, we add the client to the
pending_writes_list. Only after processing all the clients do we send
all the replies. Since the IO threads are now working asynchronously, we
can send the reply immediately after processing the client’s requests,
reducing the command latency. However, if we are using AOF=always, we
must wait for the AOF buffer to be written, in which case we revert to
the current behavior.
**IO threads dynamic adjustment**
Currently, we use an all-or-nothing approach when activating the IO
threads. The current logic is as follows: if the number of pending write
clients is greater than twice the number of threads (including the main
thread), we enable all threads; otherwise, we enable none. For example,
if 8 IO threads are defined, we enable all 8 threads if there are 16
pending clients; else, we enable none.
It makes more sense to enable partial activation of the IO threads. If
we have 10 pending clients, we will enable 5 threads, and so on. This
approach allows for a more granular and efficient allocation of
resources based on the current workload.
In addition, the user will now be able to change the number of I/O
threads at runtime. For example, when decreasing the number of threads
from 4 to 2, threads 3 and 4 will be closed after flushing their job
queues.
**Tests**
Currently, we run the io-threads tests with 4 IO threads
(443d80f168/.github/workflows/daily.yml (L353)).
This means that we will not activate the IO threads unless there are 8
(threads * 2) pending write clients per single loop, which is unlikely
to happened in most of tests, meaning the IO threads are not currently
being tested.
To enforce the main thread to always offload work to the IO threads,
regardless of the number of pending events, we add an
events-per-io-thread configuration with a default value of 2. When set
to 0, this configuration will force the main thread to always offload
work to the IO threads.
When we offload every single read/write operation to the IO threads, the
IO-threads are running with 100% CPU when running multiple tests
concurrently some tests fail as a result of larger than expected command
latencies. To address this issue, we have to add some after or wait_for
calls to some of the tests to ensure they pass with IO threads as well.
Signed-off-by: Uri Yagelnik <uriy@amazon.com>
We forgot to call sdsfreesplitres in the error path during a
nodes.conf corruption check, this function exits on the error
paths so this is just a cleanup.
Signed-off-by: bentotten <59932872+bentotten@users.noreply.github.com>
This PR updates all Redis/redis keywords to Valkey/valkey, including
variable names, comments, function names.
All sentinel test cases passed.
---------
Signed-off-by: hwware <wen.hui.ware@gmail.com>
Currently, for nested MULTI or executing WATCH in MULTI, we will return
an error but we will not abort the transaction.
```
127.0.0.1:6379> multi
OK
127.0.0.1:6379(TX)> multi
(error) ERR MULTI calls can not be nested
127.0.0.1:6379(TX)> set key value
QUEUED
127.0.0.1:6379(TX)> exec
1) OK
127.0.0.1:6379> multi
OK
127.0.0.1:6379(TX)> watch key
(error) ERR WATCH inside MULTI is not allowed
127.0.0.1:6379(TX)> set key value
QUEUED
127.0.0.1:6379(TX)> exec
1) OK
```
This is an unexpected behavior that should abort the transaction.
The number of elements returned by EXEC also doesn't match the number
of commands in MULTI.
Add the NO_MULTI flag to them so that they will
be rejected in processCommand and rejectCommand will abort the
transaction.
So there are two visible changes:
- Different words in the error messages. (Command not allowed inside a
transaction)
- Exec returns error.
Signed-off-by: Binbin <binloveplay1314@qq.com>
This PR incorporates changes related to key embedding described in the
https://github.com/redis/redis/issues/12216
With this change there will be no `key` pointer and embedded the key
within the `dictEntry`. 1 byte is used for additional bookkeeping.
Overall the saving would be 7 bytes on average.
Key changes:
New dict entry type introduced, which is now used as an entry for the
main dictionary:
```c
typedef struct {
union {
void *val;
uint64_t u64;
int64_t s64;
double d;
} v;
struct dictEntry *next; /* Next entry in the same hash bucket. */
uint8_t key_header_size; /* offset into key_buf where the key is located at. */
unsigned char key_buf[]; /* buffer with embedded key. */
} embeddedDictEntry;
```
One new function has been added to the dictType:
```c
size_t (*embedKey)(unsigned char *buf, size_t buf_len, const void *key, unsigned char *header_size);
```
Change is opt-in per dict type, hence sets, hashes and other types that
are using dictionary are not impacted.
With this change main dictionary now owns the data, so copy on insert in
dbAdd is no longer needed.
### Benchmarking results
TLDR; Around 9-10% memory usage reduction in overall memory usage for
scenario with key of 16 bytes and value of 8 bytes and 16 bytes. The
throughput per second varies but is similar or greater in most of the
run(s) with the changes against unstable (ae2d421).
---------
Signed-off-by: Harkrishn Patro <harkrisp@amazon.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
#### Description
This patch try to introduce a thread-local storage variable for each
thread to update its own `used_memory`, and then sum them together when
reading in `zmalloc_used_memory`. Then we can reduce unnecessary `lock
add` contention from atomic variable. We also add a protection if too
many threads created and the total threads number greater than 132, then
fall back to atomic operation for the threads index >= 132.
#### Problem Statement
`zmalloc` and `zfree` related functions will update the `used_memory`
atomicity for each operation, and they are called very frequency. From
the benchmark of
[memtier_benchmark-1Mkeys-load-stream-5-fields-with-100B-values-pipeline-10.yml](https://github.com/redis/redis-benchmarks-specification/blob/main/redis_benchmarks_specification/test-suites/memtier_benchmark-1Mkeys-load-stream-5-fields-with-100B-values-pipeline-10.yml)
, the cycles ratio of `zmalloc` and `zfree` are high, they are wrappers
for the lower allocator library, it should not take too much cycles. And
most of the cycles are contributed by `lock add` and `lock sub` , they
are expensive instructions. From the profiling, the metrics' update
mainly come from the main thread, use a TLS will reduce a lot of
contention.
#### Performance Boost
**Note:** This optimization should benefit common benchmark widely. I
choose below 2 scenarios to validate the performance boost in my local
environment.
| Test Suites | Performance Boost |
|-|-|
|[memtier_benchmark-1Mkeys-load-stream-5-fields-with-100B-values-pipeline-10](https://github.com/redis/redis-benchmarks-specification/blob/main/redis_benchmarks_specification/test-suites/memtier_benchmark-1Mkeys-load-stream-5-fields-with-100B-values-pipeline-10.yml)|8%|
|[memtier_benchmark-1Mkeys-load-string-with-100B-values-pipeline-10](https://github.com/redis/redis-benchmarks-specification/blob/main/redis_benchmarks_specification/test-suites/memtier_benchmark-1Mkeys-load-string-with-100B-values-pipeline-10.yml)|4%|
##### Test Env
- OS: Ubuntu 22.04.4 LTS
- Platform: Intel Xeon Platinum 8380
- Server and Client in same socket
##### Start Server
```sh
taskset -c 0-3 ~/valkey/src/valkey-server /tmp/valkey_1.conf
port 9001
bind * -::*
daemonize yes
protected-mode no
save ""
```
---------
Signed-off-by: Lipeng Zhu <lipeng.zhu@intel.com>
Co-authored-by: Wangyang Guo <wangyang.guo@intel.com>
Module Authentication using a blocking implementation currently gets
rejected when the "cluster is down" from the client timeout cron job
(`clientsCronHandleTimeout`).
This PR exempts clients blocked on Module Authentication from being
rejected here.
---------
Signed-off-by: KarthikSubbarao <karthikrs2021@gmail.com>
cluster-slots test is tesing a very fragmented slots range of a
relatively large cluster. For this reason, when run under valgrind, some
of the nodes are timing out when cluster is attempting to converge and
propagate.
This pr sets the test's cluster-node-timeout to 90000 and
cluster-ping-interval to 1000.
Signed-off-by: ranshid <ranshid@amazon.com>
Test failed in my local:
```
*** [err]: CLUSTER SLOT-STATS ORDERBY LIMIT correct response pagination, where limit is less than number of assigned slots in tests/unit/cluster/slot-stats.tcl
Expected [dict exists 0 0 1 0 2 0 3 0 4 0 16383] (context: type source line 64 file /xxx/tests/unit/cluster/slot-stats.tcl cmd {assert {[dict exists $expected_slots $slot]}} proc ::assert_slot_visibility level 1)
```
It seems that when the stat is equal, that is, when the key-count is
equal,
the qsort performance will be different. When the stat is equal, we
compare
by slot (in ascending order).
Signed-off-by: Binbin <binloveplay1314@qq.com>
We did not set a default value for limit, but it will be used
in addReplyOrderBy later, the undefined behavior may crash the
server since the value could be negative and crash will happen
in addReplyArrayLen.
An interesting reproducible example (limit reuses the value of -1):
```
> cluster slot-stats orderby key-count desc limit -1
(error) ERR Limit has to lie in between 1 and 16384 (maximum number of slots).
> cluster slot-stats orderby key-count desc
Error: Server closed the connection
```
Set the default value of limit to 16384.
---------
Signed-off-by: Binbin <binloveplay1314@qq.com>
The command provides detailed slot usage statistics upon invocation,
with initial support for key-count metric. cpu-usec (approved) and
memory-bytes (pending-approval) metrics will soon follow after the
merger of this PR.
---------
Signed-off-by: Kyle Kim <kimkyle@amazon.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
When Redis/Valkey/KeyDB is run in a cloud environment across multiple
AZ's it is preferable to keep traffic local to an AZ both for cost
reasons and for latency. This is typically done when you are enabling
reads on replicas with the READONLY command.
For this change we are creating a setting that is echo'd back in the
info command. We do not want to add the cloud SDKs as dependencies and
this is the easiest way around that. It is fairly trivial to grab the AZ
from the cloud and push that into your setting file.
Currently at Snapchat we have a custom client that after connecting
reads this from the server and will preferentially use that server if
the AZ string matches its internally configured AZ.
In the future it would be ideal if we used this information when
performing failover or even exposed it in cluster nodes.
Signed-off-by: John Sully <john@csquare.ca>
The create-cluster in utils mainly used to create a test cluster,
turning on these options is useful for testing purposes.
Signed-off-by: Binbin <binloveplay1314@qq.com>
To implement #319
1. replica is able to redirect read and write commands to it's primary
in standalone mode
* reply with "-REDIRECT primary-ip:port"
2. add a subcommand `CLIENT CAPA redirect`, a client can announce the
capability to handle redirection
* if a client can handle redirection, the data access commands (read and
write) will be redirected
3. allow `readonly` and `readwrite` command in standalone mode, may be a
breaking change
* a client with redirect capability cannot process read commands on a
replica by default
* use READONLY command can allow read commands on a replica
---------
Signed-off-by: zhaozhao.zz <zhaozhao.zz@alibaba-inc.com>
As discussed, we want to remove the old `REDIS_STATIC` flag which is no
longer relevant.
When moving from Redis to Valkey we renamed all REDIS flags in Makefile.
The REDIS_STATIC flag was renamed to SERVER_STATIC, but this change was
not updated in some of the files.
After discussing it with @madolson and @ranshid, we decided that since
this was introduced 10 years ago, and in many places in the code base we
simply use `static`, we should simplify and remove the flag entirely.
---------
Signed-off-by: Ouri Half <ourih@amazon.com>
