There is a timing issue in the test, close may arrive late, or in
freeClientAsync we will free the client in async way, which will
lead to errors in watching_clients statistics, since we will only
unwatch all keys when we truly freeClient.
Add a wait here to avoid this problem. Also fixed some outdated
comments i saw. The test was introduced in #12966.
Redis has some special commands that mark the client's state, such as
`subscribe` and `blpop`, which mark the client as `CLIENT_PUBSUB` or
`CLIENT_BLOCKED`, and we have metrics for the special use cases.
However, there are also other special commands, like `WATCH`, which
although do not have a specific flags, and should also be considered
stateful client types. For stateful clients, in many scenarios, the
connections cannot be shared in "connection pool", meaning connection
pool cannot be used. For example, whenever the `WATCH` command is
executed, a new connection is required to put the client into the "watch
state" because the watched keys are stored in the client.
If different business logic requires watching different keys, separate
connections must be used; otherwise, there will be contamination. This
also means that if a user's business heavily relies on the `WATCH`
command, a large number of connections will be required.
Recently we have encountered this situation in our platform, where some
users consume a significant number of connections when using Redis
because of `WATCH`.
I hope we can have a way to observe these special use cases and special
client connections. Here I add a few monitoring metrics:
1. `watching_clients` in `INFO` reply: The number of clients currently
in the "watching" state.
2. `total_watched_keys` in `INFO` reply: The total number of keys being
watched.
3. `watch` in `CLIENT LIST` reply: The number of keys each client is
currently watching.
Adds an ability to kill clients older than a specified age.
Also, fixed the age calculation in `catClientInfoString` to use
`commandTimeSnapshot`
instead of the old `server.unixtime`, and added missing documentation
for
`CLIENT KILL ID` to output of `CLIENT help`.
---------
Co-authored-by: Oran Agra <oran@redislabs.com>
Fix#9926 , and introduce an alternative method to prevent abuse of
transactions:
1. revert #5454 (which was blocking read-only transactions in OOM
state), and break the tie of MULTI state memory usage and the server OOM
state. Meaning that we'll limit the total memory a single client can
queue, and do that unconditionally regardless of the server being OOM or
not.
2. to prevent abuse of transactions, we use the
`client-query-buffer-limit` to restrict the size of the transaction.
Because the commands cached in the MULTI/EXEC queue have not been
executed yet, so they are also considered a part of the "query buffer"
in a broader sense. In other words, the commands in the MULTI queue and
the `querybuf` of the client together constitute the "query buffer".
When they exceed the limit, the connection will be disconnected.
The reasoning is that it's sensible to sends a single command with a
huge (1GB) argument, and it's sensible to sends a transaction with many
small commands, but it's probably not common to sends a long transaction
with many huge arguments (will consume a lot of memory before even being
executed).
If anyone runs into that, they can simply increase the
`client-query-buffer-limit` config.
P.S. To prevent DDoS attacks, unauthenticated clients have a separate
hard limit. Their query buffer should not exceed a maximum of 1MB. In
other words, if the query buffer of an unauthenticated client exceeds
1MB or the `client-query-buffer-limit` (if it is set to a value smaller
than 1MB,), the connection will be disconnected.
Fix#12785 and other race condition issues.
See the following isolated comments.
The following report was obtained using SANITIZER thread.
```sh
make SANITIZER=thread
./runtest-moduleapi --config io-threads 4 --config io-threads-do-reads yes --accurate
```
1. Fixed thread-safe issue in RM_UnblockClient()
Related discussion:
https://github.com/redis/redis/pull/12817#issuecomment-1831181220
* When blocking a client in a module using `RM_BlockClientOnKeys()` or
`RM_BlockClientOnKeysWithFlags()`
with a timeout_callback, calling RM_UnblockClient() in module threads
can lead to race conditions
in `updateStatsOnUnblock()`.
- Introduced:
Version: 6.2
PR: #7491
- Touch:
`server.stat_numcommands`, `cmd->latency_histogram`, `server.slowlog`,
and `server.latency_events`
- Harm Level: High
Potentially corrupts the memory data of `cmd->latency_histogram`,
`server.slowlog`, and `server.latency_events`
- Solution:
Differentiate whether the call to moduleBlockedClientTimedOut() comes
from the module or the main thread.
Since we can't know if RM_UnblockClient() comes from module threads, we
always assume it does and
let `updateStatsOnUnblock()` asynchronously update the unblock status.
* When error reply is called in timeout_callback(), ctx is not
thread-safe, eventually lead to race conditions in `afterErrorReply`.
- Introduced:
Version: 6.2
PR: #8217
- Touch
`server.stat_total_error_replies`, `server.errors`,
- Harm Level: High
Potentially corrupts the memory data of `server.errors`
- Solution:
Make the ctx in `timeout_callback()` with `REDISMODULE_CTX_THREAD_SAFE`,
and asynchronously reply errors to the client.
2. Made RM_Reply*() family API thread-safe
Related discussion:
https://github.com/redis/redis/pull/12817#discussion_r1408707239
Call chain: `RM_Reply*()` -> `_addReplyToBufferOrList()` -> touch
server.current_client
- Introduced:
Version: 7.2.0
PR: #12326
- Harm Level: None
Since the module fake client won't have the `CLIENT_PUSHING` flag, even
if we touch server.current_client,
we can still exit after `c->flags & CLIENT_PUSHING`.
- Solution
Checking `c->flags & CLIENT_PUSHING` earlier.
3. Made freeClient() thread-safe
Fix#12785
- Introduced:
Version: 4.0
Commit:
3fcf959e60
- Harm Level: Moderate
* Trigger assertion
It happens when the module thread calls freeClient while the io-thread
is in progress,
which just triggers an assertion, and doesn't make any race condiaions.
* Touch `server.current_client`, `server.stat_clients_type_memory`, and
`clientMemUsageBucket->clients`.
It happens between the main thread and the module threads, may cause
data corruption.
1. Error reset `server.current_client` to NULL, but theoretically this
won't happen,
because the module has already reset `server.current_client` to old
value before entering freeClient.
2. corrupts `clientMemUsageBucket->clients` in
updateClientMemUsageAndBucket().
3. Causes server.stat_clients_type_memory memory statistics to be
inaccurate.
- Solution:
* No longer counts memory usage on fake clients, to avoid updating
`server.stat_clients_type_memory` in freeClient.
* No longer resetting `server.current_client` in unlinkClient, because
the fake client won't be evicted or disconnected in the mid of the
process.
* Judgment assertion `io_threads_op == IO_THREADS_OP_IDLE` only if c is
not a fake client.
4. Fixed free client args without GIL
Related discussion:
https://github.com/redis/redis/pull/12817#discussion_r1408706695
When freeing retained strings in the module thread (refcount decr), or
using them in some way (refcount incr), we should do so while holding
the GIL,
otherwise, they might be simultaneously freed while the main thread is
processing the unblock client state.
- Introduced:
Version: 6.2.0
PR: #8141
- Harm Level: Low
Trigger assertion or double free or memory leak.
- Solution:
Documenting that module API users need to ensure any access to these
retained strings is done with the GIL locked
5. Fix adding fake client to server.clients_pending_write
It will incorrectly log the memory usage for the fake client.
Related discussion:
https://github.com/redis/redis/pull/12817#issuecomment-1851899163
- Introduced:
Version: 4.0
Commit:
9b01b64430
- Harm Level: None
Only result in NOP
- Solution:
* Don't add fake client into server.clients_pending_write
* Add c->conn assertion for updateClientMemUsageAndBucket() and
updateClientMemoryUsage() to avoid same
issue in the future.
So now it will be the responsibility of the caller of both of them to
avoid passing in fake client.
6. Fix calling RM_BlockedClientMeasureTimeStart() and
RM_BlockedClientMeasureTimeEnd() without GIL
- Introduced:
Version: 6.2
PR: #7491
- Harm Level: Low
Causes inaccuracies in command latency histogram and slow logs, but does
not corrupt memory.
- Solution:
Module API users, if know that non-thread-safe APIs will be used in
multi-threading, need to take responsibility for protecting them with
their own locks instead of the GIL, as using the GIL is too expensive.
### Other issue
1. RM_Yield is not thread-safe, fixed via #12905.
### Summarize
1. Fix thread-safe issues for `RM_UnblockClient()`, `freeClient()` and
`RM_Yield`, potentially preventing memory corruption, data disorder, or
assertion.
2. Updated docs and module test to clarify module API users'
responsibility for locking non-thread-safe APIs in multi-threading, such
as RM_BlockedClientMeasureTimeStart/End(), RM_FreeString(),
RM_RetainString(), and RM_HoldString().
### About backpot to 7.2
1. The implement of (1) is not too satisfying, would like to get more
eyes.
2. (2), (3) can be safely for backport
3. (4), (6) just modifying the module tests and updating the
documentation, no need for a backpot.
4. (5) is harmless, no need for a backpot.
---------
Co-authored-by: Oran Agra <oran@redislabs.com>
The raxFind implementation uses a special pointer value (the address of
a static string) as the "not found" value. It works as long as actual
pointers were used. However we've seen usages where long long,
non-pointer values have been used. It creates a risk that one of the
long long value precisely is the address of the special "not found"
value. This commit changes raxFind to return 1 or 0 to indicate
elementhood, and take in a new void **value to optionally return the
associated value.
By extension, this also allow the RedisModule_DictSet/Replace operations
to also safely insert integers instead of just pointers.
In INFO CLIENTS section, we already have blocked_clients and
tracking_clients. We should add a new metric showing the number of
pubsub connections, which helps performance monitoring and trouble
shooting.
Move clusterNode into cluster_legacy.h.
In order to achieve this some accessor methods
were added and also a refactor of how debugCommand
handles cluster related subcommands.
Signed-off-by: Josh Hershberg <yehoshua@redis.com>
In #12476 server.stat_client_qbuf_limit_disconnections was added. It is written in readQueryFromClient, which may be called by multiple threads when io-threads and io-threads-do-reads are turned on. Somehow we missed to make it an atomic variable.
In a long printf call with many placeholders, it's hard to see which argument
belongs to which placeholder.
The long printf-like calls in the INFO and CLIENT commands are rewritten into
pairs of (format, argument). These pairs are then rewritten to a single call with
a long format string and a long list of arguments, using a macro called FMTARGS.
The file `fmtargs.h` is added to the repo.
Co-authored-by: Madelyn Olson <34459052+madolson@users.noreply.github.com>
Add these INFO metrics:
* client_query_buffer_limit_disconnections
* client_output_buffer_limit_disconnections
Sometimes it is useful to monitor whether clients reaches size limit of
query buffer and output buffer, to decide whether we need to adjust the
buffer size limit or reduce client query payload.
A bug introduced in #11657 (7.2 RC1), causes client-eviction (#8687)
and INFO to have inaccurate memory usage metrics of MONITOR clients.
Because the type in `c->type` and the type in `getClientType()` are confusing
(in the later, `CLIENT_TYPE_NORMAL` not `CLIENT_TYPE_SLAVE`), the comment
we wrote in `updateClientMemUsageAndBucket` was wrong, and in fact that function
didn't skip monitor clients.
And since it doesn't skip monitor clients, it was wrong to delete the call for it from
`replicationFeedMonitors` (it wasn't a NOP).
That deletion could mean that the monitor client memory usage is not always up to
date (updated less frequently, but still a candidate for client eviction).
When a connection that's subscribe to a channel emits PUBLISH inside MULTI-EXEC,
the push notification messes up the EXEC response.
e.g. MULTI, PING, PUSH foo bar, PING, EXEC
the EXEC's response will contain: PONG, {message foo bar}, 1. and the second PONG
will be delivered outside the EXEC's response.
Additionally, this PR changes the order of responses in case of a plain PUBLISH (when
the current client also subscribed to it), by delivering the push after the command's
response instead of before it.
This also affects modules calling RM_PublishMessage in a similar way, so that we don't
run the risk of getting that push mixed together with the module command's response.
In the original implementation, the time complexity of the commands
is actually O(N*M), where N is the number of patterns the client is
already subscribed and M is the number of patterns to subscribe to.
The docs are all wrong about this.
Specifically, because the original client->pubsub_patterns is a list,
so we need to do listSearchKey which is O(N). In this PR, we change it
to a dict, so the search becomes O(1).
At the same time, both pubsub_channels and pubsubshard_channels are dicts.
Changing pubsub_patterns to a dictionary improves the readability and
maintainability of the code.
This will increase the size of an already large COB (one already passed
the threshold for disconnection)
This could also mean that we'll attempt to write that data to the socket
and the replica will manage to read it, which will result in an
undesired partial sync (undesired for the test)
Rather than a fixed iovcnt for connWritev, support maxiov per connection type instead.
A minor change to reduce memory for struct connection.
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Technically declaring a prototype with an empty declaration has been deprecated since the early days of C, but we never got a warning for it. C2x will apparently be introducing a breaking change if you are using this type of declarator, so Clang 15 has started issuing a warning with -pedantic. Although not apparently a problem for any of the compiler we build on, if feels like the right thing is to properly adhere to the C standard and use (void).
This PR is to fix the compilation warnings and errors generated by the latest
complier toolchain, and to add a new runner of the latest toolchain for daily CI.
## Fix various compilation warnings and errors
1) jemalloc.c
COMPILER: clang-14 with FORTIFY_SOURCE
WARNING:
```
src/jemalloc.c:1028:7: warning: suspicious concatenation of string literals in an array initialization; did you mean to separate the elements with a comma? [-Wstring-concatenation]
"/etc/malloc.conf",
^
src/jemalloc.c:1027:3: note: place parentheses around the string literal to silence warning
"\"name\" of the file referenced by the symbolic link named "
^
```
REASON: the compiler to alert developers to potential issues with string concatenation
that may miss a comma,
just like #9534 which misses a comma.
SOLUTION: use `()` to tell the compiler that these two line strings are continuous.
2) config.h
COMPILER: clang-14 with FORTIFY_SOURCE
WARNING:
```
In file included from quicklist.c:36:
./config.h:319:76: warning: attribute declaration must precede definition [-Wignored-attributes]
char *strcat(char *restrict dest, const char *restrict src) __attribute__((deprecated("please avoid use of unsafe C functions. prefer use of redis_strlcat instead")));
```
REASON: Enabling _FORTIFY_SOURCE will cause the compiler to use `strcpy()` with check,
it results in a deprecated attribute declaration after including <features.h>.
SOLUTION: move the deprecated attribute declaration from config.h to fmacro.h before "#include <features.h>".
3) networking.c
COMPILER: GCC-12
WARNING:
```
networking.c: In function ‘addReplyDouble.part.0’:
networking.c:876:21: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
876 | dbuf[start] = '$';
| ^
networking.c:868:14: note: at offset -5 into destination object ‘dbuf’ of size 5152
868 | char dbuf[MAX_LONG_DOUBLE_CHARS+32];
| ^
networking.c:876:21: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
876 | dbuf[start] = '$';
| ^
networking.c:868:14: note: at offset -6 into destination object ‘dbuf’ of size 5152
868 | char dbuf[MAX_LONG_DOUBLE_CHARS+32];
```
REASON: GCC-12 predicts that digits10() may return 9 or 10 through `return 9 + (v >= 1000000000UL)`.
SOLUTION: add an assert to let the compiler know the possible length;
4) redis-cli.c & redis-benchmark.c
COMPILER: clang-14 with FORTIFY_SOURCE
WARNING:
```
redis-benchmark.c:1621:2: warning: embedding a directive within macro arguments has undefined behavior [-Wembedded-directive] #ifdef USE_OPENSSL
redis-cli.c:3015:2: warning: embedding a directive within macro arguments has undefined behavior [-Wembedded-directive] #ifdef USE_OPENSSL
```
REASON: when _FORTIFY_SOURCE is enabled, the compiler will use the print() with
check, which is a macro. this may result in the use of directives within the macro, which
is undefined behavior.
SOLUTION: move the directives-related code out of `print()`.
5) server.c
COMPILER: gcc-13 with FORTIFY_SOURCE
WARNING:
```
In function 'lookupCommandLogic',
inlined from 'lookupCommandBySdsLogic' at server.c:3139:32:
server.c:3102:66: error: '*(robj **)argv' may be used uninitialized [-Werror=maybe-uninitialized]
3102 | struct redisCommand *base_cmd = dictFetchValue(commands, argv[0]->ptr);
| ~~~~^~~
```
REASON: The compiler thinks that the `argc` returned by `sdssplitlen()` could be 0,
resulting in an empty array of size 0 being passed to lookupCommandLogic.
this should be a false positive, `argc` can't be 0 when strings are not NULL.
SOLUTION: add an assert to let the compiler know that `argc` is positive.
6) sha1.c
COMPILER: gcc-12
WARNING:
```
In function ‘SHA1Update’,
inlined from ‘SHA1Final’ at sha1.c:195:5:
sha1.c:152:13: warning: ‘SHA1Transform’ reading 64 bytes from a region of size 0 [-Wstringop-overread]
152 | SHA1Transform(context->state, &data[i]);
| ^
sha1.c:152:13: note: referencing argument 2 of type ‘const unsigned char[64]’
sha1.c: In function ‘SHA1Final’:
sha1.c:56:6: note: in a call to function ‘SHA1Transform’
56 | void SHA1Transform(uint32_t state[5], const unsigned char buffer[64])
| ^
In function ‘SHA1Update’,
inlined from ‘SHA1Final’ at sha1.c:198:9:
sha1.c:152:13: warning: ‘SHA1Transform’ reading 64 bytes from a region of size 0 [-Wstringop-overread]
152 | SHA1Transform(context->state, &data[i]);
| ^
sha1.c:152:13: note: referencing argument 2 of type ‘const unsigned char[64]’
sha1.c: In function ‘SHA1Final’:
sha1.c:56:6: note: in a call to function ‘SHA1Transform’
56 | void SHA1Transform(uint32_t state[5], const unsigned char buffer[64])
```
REASON: due to the bug[https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80922], when
enable LTO, gcc-12 will not see `diagnostic ignored "-Wstringop-overread"`, resulting in a warning.
SOLUTION: temporarily set SHA1Update to noinline to avoid compiler warnings due
to LTO being enabled until the above gcc bug is fixed.
7) zmalloc.h
COMPILER: GCC-12
WARNING:
```
In function ‘memset’,
inlined from ‘moduleCreateContext’ at module.c:877:5,
inlined from ‘RM_GetDetachedThreadSafeContext’ at module.c:8410:5:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:59:10: warning: ‘__builtin_memset’ writing 104 bytes into a region of size 0 overflows the destination [-Wstringop-overflow=]
59 | return __builtin___memset_chk (__dest, __ch, __len,
```
REASON: due to the GCC-12 bug [https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96503],
GCC-12 cannot see alloc_size, which causes GCC to think that the actual size of memory
is 0 when checking with __glibc_objsize0().
SOLUTION: temporarily set malloc-related interfaces to `noinline` to avoid compiler warnings
due to LTO being enabled until the above gcc bug is fixed.
## Other changes
1) Fixed `ps -p [pid]` doesn't output `<defunct>` when using procps 4.x causing `replication
child dies when parent is killed - diskless` test to fail.
2) Add a new fortify CI with GCC-13 and ubuntu-lunar docker image.
this pr fix two wrongs：
1. When client’s querybuf is pre-allocated for a fat argv, we need to update the
querybuf_peak of the client immediately to completely avoid the unexpected
shrinking of querybuf in the next clientCron (before data arrives to set the peak).
2. the protocol's bulklen does not include `\r\n`, but the allocation and the data we
read does. so in `clientsCronResizeQueryBuffer`, the `resize` or `querybuf_peak`
should add these 2 bytes.
the first bug is likely to hit us on large payloads over slow connections, in which case
transferring the payload can take longer and a cron event will be triggered (specifically
if there are not a lot of clients)
* Add RM_ReplyWithErrorFormat that can support format
Reply with the error create from a printf format and arguments.
If the error code is already passed in the string 'fmt', the error
code provided is used, otherwise the string "-ERR " for the generic
error code is automatically added.
The usage is, for example:
RedisModule_ReplyWithErrorFormat(ctx, "An error: %s", "foo");
RedisModule_ReplyWithErrorFormat(ctx, "-WRONGTYPE Wrong Type: %s", "foo");
The function always returns REDISMODULE_OK.
## Issue
When we use GCC-12 later or clang 9.0 later to build with `-D_FORTIFY_SOURCE=3`,
we can see the following buffer overflow:
```
=== REDIS BUG REPORT START: Cut & paste starting from here ===
6263:M 06 Apr 2023 08:59:12.915 # Redis 255.255.255 crashed by signal: 6, si_code: -6
6263:M 06 Apr 2023 08:59:12.915 # Crashed running the instruction at: 0x7f03d59efa7c
------ STACK TRACE ------
EIP:
/lib/x86_64-linux-gnu/libc.so.6(pthread_kill+0x12c)[0x7f03d59efa7c]
Backtrace:
/lib/x86_64-linux-gnu/libc.so.6(+0x42520)[0x7f03d599b520]
/lib/x86_64-linux-gnu/libc.so.6(pthread_kill+0x12c)[0x7f03d59efa7c]
/lib/x86_64-linux-gnu/libc.so.6(raise+0x16)[0x7f03d599b476]
/lib/x86_64-linux-gnu/libc.so.6(abort+0xd3)[0x7f03d59817f3]
/lib/x86_64-linux-gnu/libc.so.6(+0x896f6)[0x7f03d59e26f6]
/lib/x86_64-linux-gnu/libc.so.6(__fortify_fail+0x2a)[0x7f03d5a8f76a]
/lib/x86_64-linux-gnu/libc.so.6(+0x1350c6)[0x7f03d5a8e0c6]
src/redis-server 127.0.0.1:25111(+0xd5e80)[0x557cddd3be80]
src/redis-server 127.0.0.1:25111(feedReplicationBufferWithObject+0x78)[0x557cddd3c768]
src/redis-server 127.0.0.1:25111(replicationFeedSlaves+0x1a4)[0x557cddd3cbc4]
src/redis-server 127.0.0.1:25111(+0x8721a)[0x557cddced21a]
src/redis-server 127.0.0.1:25111(call+0x47a)[0x557cddcf38ea]
src/redis-server 127.0.0.1:25111(processCommand+0xbf4)[0x557cddcf4aa4]
src/redis-server 127.0.0.1:25111(processInputBuffer+0xe6)[0x557cddd22216]
src/redis-server 127.0.0.1:25111(readQueryFromClient+0x3a8)[0x557cddd22898]
src/redis-server 127.0.0.1:25111(+0x1b9134)[0x557cdde1f134]
src/redis-server 127.0.0.1:25111(aeMain+0x119)[0x557cddce5349]
src/redis-server 127.0.0.1:25111(main+0x466)[0x557cddcd6716]
/lib/x86_64-linux-gnu/libc.so.6(+0x29d90)[0x7f03d5982d90]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80)[0x7f03d5982e40]
src/redis-server 127.0.0.1:25111(_start+0x25)[0x557cddcd7025]
```
The main reason is that when FORTIFY_SOURCE is enabled, GCC or clang will enhance some
common functions, such as `strcpy`, `memcpy`, `fgets`, etc, so that they can detect buffer
overflow errors and stop program execution, thus improving the safety of the program.
We use `zmalloc_usable_size()` everywhere to use memory blocks, but that is an abuse since the
malloc_usable_size() isn't meant for this kind of use, it is for diagnostics only. That is also why the
behavior is flaky when built with _FORTIFY_SOURCE, the compiler can sense that we reach outside
the allocated block and SIGABRT.
### Solution
If we need to use the additional memory we got, we need to use a dummy realloc with `alloc_size` attribute
and no inlining, (see `extend_to_usable`) to let the compiler see the large of memory we need to use.
This can either be an implicit call inside `z*usable` that returns the size, so that the caller doesn't have any
other worry, or it can be a normal zmalloc call which means that if the caller wants to use
zmalloc_usable_size it must also use extend_to_usable.
### Changes
This PR does the following:
1) rename the current z[try]malloc_usable family to z[try]malloc_internal and don't expose them to users outside zmalloc.c,
2) expose a new set of `z[*]_usable` family that use z[*]_internal and `extend_to_usable()` implicitly, the caller gets the
size of the allocation and it is safe to use.
3) go over all the users of `zmalloc_usable_size` and convert them to use the `z[*]_usable` family if possible.
4) in the places where the caller can't use `z[*]_usable` and store the real size, and must still rely on zmalloc_usable_size,
we still make sure that the allocation used `z[*]_usable` (which has a call to `extend_to_usable()`) and ignores the
returning size, this way a later call to `zmalloc_usable_size` is still safe.
[4] was done for module.c and listpack.c, all the others places (sds, reply proto list, replication backlog, client->buf)
are using [3].
Co-authored-by: Oran Agra <oran@redislabs.com>
In #11012, we changed the way command durations were computed to handle the same command being executed multiple times. This commit fixes some misses from that commit.
* Wait commands were not correctly reporting their duration if the timeout was reached.
* Multi/scripts/and modules with RM_Call were not properly resetting the duration between inner calls, leading to them reporting cumulative duration.
* When a blocked client is freed, the call and duration are always discarded.
This commit also adds an assert if the duration is not properly reset, potentially indicating that a report to call statistics was missed. The assert potentially be removed in the future, as it's mainly intended to detect misses in tests.
The reply schema validator is failing since the recent changes to introspection.tcl that use the RESET command, this happens because this test forces RESP3, but RESET command didn't respect that and set back RESP2.
This PR allows clients to send information about the client library to redis
to be displayed in CLIENT LIST and CLIENT INFO.
Currently supports:
`CLIENT [lib-name | lib-ver] <value>`
Client libraries are expected to pipeline these right after AUTH, and ignore
the failure in case they're talking to an older version of redis.
These will be shown in CLIENT LIST and CLIENT INFO as:
* `lib-name` - meant to hold the client library name.
* `lib-ver` - meant to hold the client library version.
The values cannot contain spaces, newlines and any wild ASCII characters,
but all other normal chars are accepted, e.g `.`, `=` etc (same as CLIENT NAME).
The RESET command does NOT clear these, but they can be cleared to the
default by sending a command with a blank string.
Co-authored-by: Oran Agra <oran@redislabs.com>
Allow running blocking commands from within a module using `RM_Call`.
Today, when `RM_Call` is used, the fake client that is used to run command
is marked with `CLIENT_DENY_BLOCKING` flag. This flag tells the command
that it is not allowed to block the client and in case it needs to block, it must
fallback to some alternative (either return error or perform some default behavior).
For example, `BLPOP` fallback to simple `LPOP` if it is not allowed to block.
All the commands must respect the `CLIENT_DENY_BLOCKING` flag (including
module commands). When the command invocation finished, Redis asserts that
the client was not blocked.
This PR introduces the ability to call blocking command using `RM_Call` by
passing a callback that will be called when the client will get unblocked.
In order to do that, the user must explicitly say that he allow to perform blocking
command by passing a new format specifier argument, `K`, to the `RM_Call`
function. This new flag will tell Redis that it is allow to run blocking command
and block the client. In case the command got blocked, Redis will return a new
type of call reply (`REDISMODULE_REPLY_PROMISE`). This call reply indicates
that the command got blocked and the user can set the on_unblocked handler using
`RM_CallReplyPromiseSetUnblockHandler`.
When clients gets unblocked, it eventually reaches `processUnblockedClients` function.
This is where we check if the client is a fake module client and if it is, we call the unblock
callback instead of performing the usual unblock operations.
**Notice**: `RM_CallReplyPromiseSetUnblockHandler` must be called atomically
along side the command invocation (without releasing the Redis lock in between).
In addition, unlike other CallReply types, the promise call reply must be released
by the module when the Redis GIL is acquired.
The module can abort the execution on the blocking command (if it was not yet
executed) using `RM_CallReplyPromiseAbort`. the API will return `REDISMODULE_OK`
on success and `REDISMODULE_ERR` if the operation is already executed.
**Notice** that in case of misbehave module, Abort might finished successfully but the
operation will not really be aborted. This can only happened if the module do not respect
the disconnect callback of the blocked client.
For pure Redis commands this can not happened.
### Atomicity Guarantees
The API promise that the unblock handler will run atomically as an execution unit.
This means that all the operation performed on the unblock handler will be wrapped
with a multi exec transaction when replicated to the replica and AOF.
The API **do not** grantee any other atomicity properties such as when the unblock
handler will be called. This gives us the flexibility to strengthen the grantees (or not)
in the future if we will decide that we need a better guarantees.
That said, the implementation **does** provide a better guarantees when performing
pure Redis blocking command like `BLPOP`. In this case the unblock handler will run
atomically with the operation that got unblocked (for example, in case of `BLPOP`, the
unblock handler will run atomically with the `LPOP` operation that run when the command
got unblocked). This is an implementation detail that might be change in the future and the
module writer should not count on that.
### Calling blocking commands while running on script mode (`S`)
`RM_Call` script mode (`S`) was introduced on #0372. It is used for usecases where the
command that was invoked on `RM_Call` comes from a user input and we want to make
sure the user will not run dangerous commands like `shutdown`. Some command, such
as `BLPOP`, are marked with `NO_SCRIPT` flag, which means they will not be allowed on
script mode. Those commands are marked with `NO_SCRIPT` just because they are
blocking commands and not because they are dangerous. Now that we can run blocking
commands on RM_Call, there is no real reason not to allow such commands on script mode.
The underline problem is that the `NO_SCRIPT` flag is abused to also mark some of the
blocking commands (notice that those commands know not to block the client if it is not
allowed to do so, and have a fallback logic to such cases. So even if those commands
were not marked with `NO_SCRIPT` flag, it would not harm Redis, and today we can
already run those commands within multi exec).
In addition, not all blocking commands are marked with `NO_SCRIPT` flag, for example
`blmpop` are not marked and can run from within a script.
Those facts shows that there are some ambiguity about the meaning of the `NO_SCRIPT`
flag, and its not fully clear where it should be use.
The PR suggest that blocking commands should not be marked with `NO_SCRIPT` flag,
those commands should handle `CLIENT_DENY_BLOCKING` flag and only block when
it's safe (like they already does today). To achieve that, the PR removes the `NO_SCRIPT`
flag from the following commands:
* `blmove`
* `blpop`
* `brpop`
* `brpoplpush`
* `bzpopmax`
* `bzpopmin`
* `wait`
This might be considered a breaking change as now, on scripts, instead of getting
`command is not allowed from script` error, the user will get some fallback behavior
base on the command implementation. That said, the change matches the behavior
of scripts and multi exec with respect to those commands and allow running them on
`RM_Call` even when script mode is used.
### Additional RedisModule API and changes
* `RM_BlockClientSetPrivateData` - Set private data on the blocked client without the
need to unblock the client. This allows up to set the promise CallReply as the private
data of the blocked client and abort it if the client gets disconnected.
* `RM_BlockClientGetPrivateData` - Return the current private data set on a blocked client.
We need it so we will have access to this private data on the disconnect callback.
* On RM_Call, the returned reply will be added to the auto memory context only if auto
memory is enabled, this allows us to keep the call reply for longer time then the context
lifetime and does not force an unneeded borrow relationship between the CallReply and
the RedisModuleContext.
This change adds new module callbacks that can override the default password based authentication associated with ACLs. With this, Modules can register auth callbacks through which they can implement their own Authentication logic. When `AUTH` and `HELLO AUTH ...` commands are used, Module based authentication is attempted and then normal password based authentication is attempted if needed.
The new Module APIs added in this PR are - `RM_RegisterCustomAuthCallback` and `RM_BlockClientOnAuth` and `RedisModule_ACLAddLogEntryByUserName `.
Module based authentication will be attempted for all Redis users (created through the ACL SETUSER cmd or through Module APIs) even if the Redis user does not exist at the time of the command. This gives a chance for the Module to create the RedisModule user and then authenticate via the RedisModule API - from the custom auth callback.
For the AUTH command, we will support both variations - `AUTH <username> <password>` and `AUTH <password>`. In case of the `AUTH <password>` variation, the custom auth callbacks are triggered with “default” as the username and password as what is provided.
### RedisModule_RegisterCustomAuthCallback
```
void RM_RegisterCustomAuthCallback(RedisModuleCtx *ctx, RedisModuleCustomAuthCallback cb) {
```
This API registers a callback to execute to prior to normal password based authentication. Multiple callbacks can be registered across different modules. These callbacks are responsible for either handling the authentication, each authenticating the user or explicitly denying, or deferring it to other authentication mechanisms. Callbacks are triggered in the order they were registered. When a Module is unloaded, all the auth callbacks registered by it are unregistered. The callbacks are attempted, in the order of most recently registered callbacks, when the AUTH/HELLO (with AUTH field is provided) commands are called. The callbacks will be called with a module context along with a username and a password, and are expected to take one of the following actions:
(1) Authenticate - Use the RM_Authenticate* API successfully and return `REDISMODULE_AUTH_HANDLED`. This will immediately end the auth chain as successful and add the OK reply.
(2) Block a client on authentication - Use the `RM_BlockClientOnAuth` API and return `REDISMODULE_AUTH_HANDLED`. Here, the client will be blocked until the `RM_UnblockClient `API is used which will trigger the auth reply callback (provided earlier through the `RM_BlockClientOnAuth`). In this reply callback, the Module should authenticate, deny or skip handling authentication.
(3) Deny Authentication - Return `REDISMODULE_AUTH_HANDLED` without authenticating or blocking the client. Optionally, `err` can be set to a custom error message. This will immediately end the auth chain as unsuccessful and add the ERR reply.
(4) Skip handling Authentication - Return `REDISMODULE_AUTH_NOT_HANDLED` without blocking the client. This will allow the engine to attempt the next custom auth callback.
If none of the callbacks authenticate or deny auth, then password based auth is attempted and will authenticate or add failure logs and reply to the clients accordingly.
### RedisModule_BlockClientOnAuth
```
RedisModuleBlockedClient *RM_BlockClientOnAuth(RedisModuleCtx *ctx, RedisModuleCustomAuthCallback reply_callback,
void (*free_privdata)(RedisModuleCtx*,void*))
```
This API can only be used from a Module from the custom auth callback. If a client is not in the middle of custom module based authentication, ERROR is returned. Otherwise, the client is blocked and the `RedisModule_BlockedClient` is returned similar to the `RedisModule_BlockClient` API.
### RedisModule_ACLAddLogEntryByUserName
```
int RM_ACLAddLogEntryByUserName(RedisModuleCtx *ctx, RedisModuleString *username, RedisModuleString *object, RedisModuleACLLogEntryReason reason)
```
Adds a new entry in the ACL log with the `username` RedisModuleString provided. This simplifies the Module usage because now, developers do not need to create a Module User just to add an error ACL Log entry. Aside from accepting username (RedisModuleString) instead of a RedisModuleUser, it is the same as the existing `RedisModule_ACLAddLogEntry` API.
### Breaking changes
- HELLO command - Clients can now only set the client name and RESP protocol from the `HELLO` command if they are authenticated. Also, we now finish command arg validation first and return early with a ERR reply if any arg is invalid. This is to avoid mutating the client name / RESP from a command that would have failed on invalid arguments.
### Notable behaviors
- Module unblocking - Now, we will not allow Modules to block the client from inside the context of a reply callback (triggered from the Module unblock flow `moduleHandleBlockedClients`).
---------
Co-authored-by: Madelyn Olson <34459052+madolson@users.noreply.github.com>
Replace NBSP character (0xC2 0xA0) with space (0x20).
Looks like that was originally added due to misconfigured editor which seems to have been fixed by now.
Implementing the WAITAOF functionality which would allow the user to
block until a specified number of Redises have fsynced all previous write
commands to the AOF.
Syntax: `WAITAOF <num_local> <num_replicas> <timeout>`
Response: Array containing two elements: num_local, num_replicas
num_local is always either 0 or 1 representing the local AOF on the master.
num_replicas is the number of replicas that acknowledged the a replication
offset of the last write being fsynced to the AOF.
Returns an error when called on replicas, or when called with non-zero
num_local on a master with AOF disabled, in all other cases the response
just contains number of fsync copies.
Main changes:
* Added code to keep track of replication offsets that are confirmed to have
been fsynced to disk.
* Keep advancing master_repl_offset even when replication is disabled (and
there's no replication backlog, only if there's an AOF enabled).
This way we can use this command and it's mechanisms even when replication
is disabled.
* Extend REPLCONF ACK to `REPLCONF ACK <ofs> FACK <ofs>`, the FACK
will be appended only if there's an AOF on the replica, and already ignored on
old masters (thus backwards compatible)
* WAIT now no longer wait for the replication offset after your last command, but
rather the replication offset after your last write (or read command that caused
propagation, e.g. lazy expiry).
Unrelated changes:
* WAIT command respects CLIENT_DENY_BLOCKING (not just CLIENT_MULTI)
Implementation details:
* Add an atomic var named `fsynced_reploff_pending` that's updated
(usually by the bio thread) and later copied to the main `fsynced_reploff`
variable (only if the AOF base file exists).
I.e. during the initial AOF rewrite it will not be used as the fsynced offset
since the AOF base is still missing.
* Replace close+fsync bio job with new BIO_CLOSE_AOF (AOF specific)
job that will also update fsync offset the field.
* Handle all AOF jobs (BIO_CLOSE_AOF, BIO_AOF_FSYNC) in the same bio
worker thread, to impose ordering on their execution. This solves a
race condition where a job could set `fsynced_reploff_pending` to a higher
value than another pending fsync job, resulting in indicating an offset
for which parts of the data have not yet actually been fsynced.
Imposing an ordering on the jobs guarantees that fsync jobs are executed
in increasing order of replication offset.
* Drain bio jobs when switching `appendfsync` to "always"
This should prevent a write race between updates to `fsynced_reploff_pending`
in the main thread (`flushAppendOnlyFile` when set to ALWAYS fsync), and
those done in the bio thread.
* Drain the pending fsync when starting over a new AOF to avoid race conditions
with the previous AOF offsets overriding the new one (e.g. after switching to
replicate from a new master).
* Make sure to update the fsynced offset at the end of the initial AOF rewrite.
a must in case there are no additional writes that trigger a periodic fsync,
specifically for a replica that does a full sync.
Limitations:
It is possible to write a module and a Lua script that propagate to the AOF and doesn't
propagate to the replication stream. see REDISMODULE_ARGV_NO_REPLICAS and luaRedisSetReplCommand.
These features are incompatible with the WAITAOF command, and can result
in two bad cases. The scenario is that the user executes command that only
propagates to AOF, and then immediately
issues a WAITAOF, and there's no further writes on the replication stream after that.
1. if the the last thing that happened on the replication stream is a PING
(which increased the replication offset but won't trigger an fsync on the replica),
then the client would hang forever (will wait for an fack that the replica will never
send sine it doesn't trigger any fsyncs).
2. if the last thing that happened is a write command that got propagated properly,
then WAITAOF will be released immediately, without waiting for an fsync (since
the offset didn't change)
Refactoring:
* Plumbing to allow bio worker to handle multiple job types
This introduces infrastructure necessary to allow BIO workers to
not have a 1-1 mapping of worker to job-type. This allows in the
future to assign multiple job types to a single worker, either as
a performance/resource optimization, or as a way of enforcing
ordering between specific classes of jobs.
Co-authored-by: Oran Agra <oran@redislabs.com>
This bug seems to be there forever, CLIENT REPLY OFF|SKIP will
mark the client with CLIENT_REPLY_OFF or CLIENT_REPLY_SKIP flags.
With these flags, prepareClientToWrite called by addReply* will
return C_ERR directly. So the client can't receive the Pub/Sub
messages and any other push notifications, e.g client side tracking.
In this PR, we adding a CLIENT_PUSHING flag, disables the reply
silencing flags. When adding push replies, set the flag, after the reply,
clear the flag. Then add the flag check in prepareClientToWrite.
Fixes#11874
Note, the SUBSCRIBE command response is a bit awkward,
see https://github.com/redis/redis-doc/pull/2327
Co-authored-by: Oran Agra <oran@redislabs.com>
Work in progress towards implementing a reply schema as part of COMMAND DOCS, see #9845
Since ironing the details of the reply schema of each and every command can take a long time, we
would like to merge this PR when the infrastructure is ready, and let this mature in the unstable branch.
Meanwhile the changes of this PR are internal, they are part of the repo, but do not affect the produced build.
### Background
In #9656 we add a lot of information about Redis commands, but we are missing information about the replies
### Motivation
1. Documentation. This is the primary goal.
2. It should be possible, based on the output of COMMAND, to be able to generate client code in typed
languages. In order to do that, we need Redis to tell us, in detail, what each reply looks like.
3. We would like to build a fuzzer that verifies the reply structure (for now we use the existing
testsuite, see the "Testing" section)
### Schema
The idea is to supply some sort of schema for the various replies of each command.
The schema will describe the conceptual structure of the reply (for generated clients), as defined in RESP3.
Note that the reply structure itself may change, depending on the arguments (e.g. `XINFO STREAM`, with
and without the `FULL` modifier)
We decided to use the standard json-schema (see https://json-schema.org/) as the reply-schema.
Example for `BZPOPMIN`:
```
"reply_schema": {
"oneOf": [
{
"description": "Timeout reached and no elements were popped.",
"type": "null"
},
{
"description": "The keyname, popped member, and its score.",
"type": "array",
"minItems": 3,
"maxItems": 3,
"items": [
{
"description": "Keyname",
"type": "string"
},
{
"description": "Member",
"type": "string"
},
{
"description": "Score",
"type": "number"
}
]
}
]
}
```
#### Notes
1. It is ok that some commands' reply structure depends on the arguments and it's the caller's responsibility
to know which is the relevant one. this comes after looking at other request-reply systems like OpenAPI,
where the reply schema can also be oneOf and the caller is responsible to know which schema is the relevant one.
2. The reply schemas will describe RESP3 replies only. even though RESP3 is structured, we want to use reply
schema for documentation (and possibly to create a fuzzer that validates the replies)
3. For documentation, the description field will include an explanation of the scenario in which the reply is sent,
including any relation to arguments. for example, for `ZRANGE`'s two schemas we will need to state that one
is with `WITHSCORES` and the other is without.
4. For documentation, there will be another optional field "notes" in which we will add a short description of
the representation in RESP2, in case it's not trivial (RESP3's `ZRANGE`'s nested array vs. RESP2's flat
array, for example)
Given the above:
1. We can generate the "return" section of all commands in [redis-doc](https://redis.io/commands/)
(given that "description" and "notes" are comprehensive enough)
2. We can generate a client in a strongly typed language (but the return type could be a conceptual
`union` and the caller needs to know which schema is relevant). see the section below for RESP2 support.
3. We can create a fuzzer for RESP3.
### Limitations (because we are using the standard json-schema)
The problem is that Redis' replies are more diverse than what the json format allows. This means that,
when we convert the reply to a json (in order to validate the schema against it), we lose information (see
the "Testing" section below).
The other option would have been to extend the standard json-schema (and json format) to include stuff
like sets, bulk-strings, error-string, etc. but that would mean also extending the schema-validator - and that
seemed like too much work, so we decided to compromise.
Examples:
1. We cannot tell the difference between an "array" and a "set"
2. We cannot tell the difference between simple-string and bulk-string
3. we cannot verify true uniqueness of items in commands like ZRANGE: json-schema doesn't cover the
case of two identical members with different scores (e.g. `[["m1",6],["m1",7]]`) because `uniqueItems`
compares (member,score) tuples and not just the member name.
### Testing
This commit includes some changes inside Redis in order to verify the schemas (existing and future ones)
are indeed correct (i.e. describe the actual response of Redis).
To do that, we added a debugging feature to Redis that causes it to produce a log of all the commands
it executed and their replies.
For that, Redis needs to be compiled with `-DLOG_REQ_RES` and run with
`--reg-res-logfile <file> --client-default-resp 3` (the testsuite already does that if you run it with
`--log-req-res --force-resp3`)
You should run the testsuite with the above args (and `--dont-clean`) in order to make Redis generate
`.reqres` files (same dir as the `stdout` files) which contain request-response pairs.
These files are later on processed by `./utils/req-res-log-validator.py` which does:
1. Goes over req-res files, generated by redis-servers, spawned by the testsuite (see logreqres.c)
2. For each request-response pair, it validates the response against the request's reply_schema
(obtained from the extended COMMAND DOCS)
5. In order to get good coverage of the Redis commands, and all their different replies, we chose to use
the existing redis test suite, rather than attempt to write a fuzzer.
#### Notes about RESP2
1. We will not be able to use the testing tool to verify RESP2 replies (we are ok with that, it's time to
accept RESP3 as the future RESP)
2. Since the majority of the test suite is using RESP2, and we want the server to reply with RESP3
so that we can validate it, we will need to know how to convert the actual reply to the one expected.
- number and boolean are always strings in RESP2 so the conversion is easy
- objects (maps) are always a flat array in RESP2
- others (nested array in RESP3's `ZRANGE` and others) will need some special per-command
handling (so the client will not be totally auto-generated)
Example for ZRANGE:
```
"reply_schema": {
"anyOf": [
{
"description": "A list of member elements",
"type": "array",
"uniqueItems": true,
"items": {
"type": "string"
}
},
{
"description": "Members and their scores. Returned in case `WITHSCORES` was used.",
"notes": "In RESP2 this is returned as a flat array",
"type": "array",
"uniqueItems": true,
"items": {
"type": "array",
"minItems": 2,
"maxItems": 2,
"items": [
{
"description": "Member",
"type": "string"
},
{
"description": "Score",
"type": "number"
}
]
}
}
]
}
```
### Other changes
1. Some tests that behave differently depending on the RESP are now being tested for both RESP,
regardless of the special log-req-res mode ("Pub/Sub PING" for example)
2. Update the history field of CLIENT LIST
3. Added basic tests for commands that were not covered at all by the testsuite
### TODO
- [x] (maybe a different PR) add a "condition" field to anyOf/oneOf schemas that refers to args. e.g.
when `SET` return NULL, the condition is `arguments.get||arguments.condition`, for `OK` the condition
is `!arguments.get`, and for `string` the condition is `arguments.get` - https://github.com/redis/redis/issues/11896
- [x] (maybe a different PR) also run `runtest-cluster` in the req-res logging mode
- [x] add the new tests to GH actions (i.e. compile with `-DLOG_REQ_RES`, run the tests, and run the validator)
- [x] (maybe a different PR) figure out a way to warn about (sub)schemas that are uncovered by the output
of the tests - https://github.com/redis/redis/issues/11897
- [x] (probably a separate PR) add all missing schemas
- [x] check why "SDOWN is triggered by misconfigured instance replying with errors" fails with --log-req-res
- [x] move the response transformers to their own file (run both regular, cluster, and sentinel tests - need to
fight with the tcl including mechanism a bit)
- [x] issue: module API - https://github.com/redis/redis/issues/11898
- [x] (probably a separate PR): improve schemas: add `required` to `object`s - https://github.com/redis/redis/issues/11899
Co-authored-by: Ozan Tezcan <ozantezcan@gmail.com>
Co-authored-by: Hanna Fadida <hanna.fadida@redislabs.com>
Co-authored-by: Oran Agra <oran@redislabs.com>
Co-authored-by: Shaya Potter <shaya@redislabs.com>
When no-touch mode is enabled, the client will not touch LRU/LFU of the
keys it accesses, except when executing command `TOUCH`.
This allows inspecting or modifying the key-space without affecting their eviction.
Changes:
- A command `CLIENT NO-TOUCH ON|OFF` to switch on and off this mode.
- A client flag `#define CLIENT_NOTOUCH (1ULL<<45)`, which can be shown
with `CLIENT INFO`, by the letter "T" in the "flags" field.
- Clear `NO-TOUCH` flag in `clearClientConnectionState`, which is used by `RESET`
command and resetting temp clients used by modules.
- Also clear `NO-EVICT` flag in `clearClientConnectionState`, this might have been an
oversight, spotted by @madolson.
- A test using `DEBUG OBJECT` command to verify that LRU stat is not touched when
no-touch mode is on.
Co-authored-by: chentianjie <chentianjie@alibaba-inc.com>
Co-authored-by: Madelyn Olson <34459052+madolson@users.noreply.github.com>
Co-authored-by: sundb <sundbcn@gmail.com>
A simple HELLO command to a password protected Redis server replies
with an error with another command suggestion. This omits protocol version
from HELLO command arguments which causes another error.
This PR adds the protocol version in the command suggestion.
We have cases where we print information (might be important but by
no means an error indicator) with the LL_WARNING level.
Demoting these to LL_NOTICE:
- oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
- User requested shutdown...
This is also true for cases that we encounter a rare but normal situation.
Demoting to LL_NOTICE. Examples:
- AOF was enabled but there is already another background operation. An AOF background was scheduled to start when possible.
- Connection with master lost.
base on yoav-steinberg's https://github.com/redis/redis/pull/10650#issuecomment-1112280554
and yossigo's https://github.com/redis/redis/pull/10650#pullrequestreview-967677676
* Make it clear that current_client is the root client that was called by
external connection
* add executing_client which is the client that runs the current command
(can be a module or a script)
* Remove script_caller that was used for commands that have CLIENT_SCRIPT
to get the client that called the script. in most cases, that's the current_client,
and in others (when being called from a module), it could be an intermediate
client when we actually want the original one used by the external connection.
bugfixes:
* RM_Call with C flag should log ACL errors with the requested user rather than
the one used by the original client, this also solves a crash when RM_Call is used
with C flag from a detached thread safe context.
* addACLLogEntry would have logged info about the script_caller, but in case the
script was issued by a module command we actually want the current_client. the
exception is when RM_Call is called from a timer event, in which case we don't
have a current_client.
behavior changes:
* client side tracking for scripts now tracks the keys that are read by the script
instead of the keys that are declared by the caller for EVAL
other changes:
* Log both current_client and executing_client in the crash log.
* remove prepareLuaClient and resetLuaClient, being dead code that was forgotten.
* remove scriptTimeSnapshot and snapshot_time and instead add cmd_time_snapshot
that serves all commands and is reset only when execution nesting starts.
* remove code to propagate CLIENT_FORCE_REPL from the executed command
to the script caller since scripts aren't propagated anyway these days and anyway
this flag wouldn't have had an effect since CLIENT_PREVENT_PROP is added by scriptResetRun.
* fix a module GIL violation issue in afterSleep that was introduced in #10300 (unreleased)
If we have integer scores on the sorted set we're not using the fastest way
to reply by calling `d2string` which uses `double2ll` and `ll2string` when it can,
instead of `fpconv_dtoa`.
This results by some 50% performance improvement in certain cases of integer
scores for both RESP2 and RESP3, and no apparent impact on double scores.
Co-authored-by: Oran Agra <oran@redislabs.com>
Introduce .is_local method to connection, and implement for TCP/TLS/
Unix socket, also drop 'int islocalClient(client *c)'. Then we can
hide the detail into the specific connection types.
Uplayer tests a connection is local or not by abstract method only.
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
*TL;DR*
---------------------------------------
Following the discussion over the issue [#7551](https://github.com/redis/redis/issues/7551)
We decided to refactor the client blocking code to eliminate some of the code duplications
and to rebuild the infrastructure better for future key blocking cases.
*In this PR*
---------------------------------------
1. reprocess the command once a client becomes unblocked on key (instead of running
custom code for the unblocked path that's different than the one that would have run if
blocking wasn't needed)
2. eliminate some (now) irrelevant code for handling unblocking lists/zsets/streams etc...
3. modify some tests to intercept the error in cases of error on reprocess after unblock (see
details in the notes section below)
4. replace '$' on the client argv with current stream id. Since once we reprocess the stream
XREAD we need to read from the last msg and not wait for new msg in order to prevent
endless block loop.
5. Added statistics to the info "Clients" section to report the:
* `total_blocking_keys` - number of blocking keys
* `total_blocking_keys_on_nokey` - number of blocking keys which have at least 1 client
which would like
to be unblocked on when the key is deleted.
6. Avoid expiring unblocked key during unblock. Previously we used to lookup the unblocked key
which might have been expired during the lookup. Now we lookup the key using NOTOUCH and
NOEXPIRE to avoid deleting it at this point, so propagating commands in blocked.c is no longer needed.
7. deprecated command flags. We decided to remove the CMD_CALL_STATS and CMD_CALL_SLOWLOG
and make an explicit verification in the call() function in order to decide if stats update should take place.
This should simplify the logic and also mitigate existing issues: for example module calls which are
triggered as part of AOF loading might still report stats even though they are called during AOF loading.
*Behavior changes*
---------------------------------------------------
1. As this implementation prevents writing dedicated code handling unblocked streams/lists/zsets,
since we now re-process the command once the client is unblocked some errors will be reported differently.
The old implementation used to issue
``UNBLOCKED the stream key no longer exists``
in the following cases:
- The stream key has been deleted (ie. calling DEL)
- The stream and group existed but the key type was changed by overriding it (ie. with set command)
- The key not longer exists after we swapdb with a db which does not contains this key
- After swapdb when the new db has this key but with different type.
In the new implementation the reported errors will be the same as if the command was processed after effect:
**NOGROUP** - in case key no longer exists, or **WRONGTYPE** in case the key was overridden with a different type.
2. Reprocessing the command means that some checks will be reevaluated once the
client is unblocked.
For example, ACL rules might change since the command originally was executed and
will fail once the client is unblocked.
Another example is OOM condition checks which might enable the command to run and
block but fail the command reprocess once the client is unblocked.
3. One of the changes in this PR is that no command stats are being updated once the
command is blocked (all stats will be updated once the client is unblocked). This implies
that when we have many clients blocked, users will no longer be able to get that information
from the command stats. However the information can still be gathered from the client list.
**Client blocking**
---------------------------------------------------
the blocking on key will still be triggered the same way as it is done today.
in order to block the current client on list of keys, the call to
blockForKeys will still need to be made which will perform the same as it is today:
* add the client to the list of blocked clients on each key
* keep the key with a matching list node (position in the global blocking clients list for that key)
in the client private blocking key dict.
* flag the client with CLIENT_BLOCKED
* update blocking statistics
* register the client on the timeout table
**Key Unblock**
---------------------------------------------------
Unblocking a specific key will be triggered (same as today) by calling signalKeyAsReady.
the implementation in that part will stay the same as today - adding the key to the global readyList.
The reason to maintain the readyList (as apposed to iterating over all clients blocked on the specific key)
is in order to keep the signal operation as short as possible, since it is called during the command processing.
The main change is that instead of going through a dedicated code path that operates the blocked command
we will just call processPendingCommandsAndResetClient.
**ClientUnblock (keys)**
---------------------------------------------------
1. Unblocking clients on keys will be triggered after command is
processed and during the beforeSleep
8. the general schema is:
9. For each key *k* in the readyList:
```
For each client *c* which is blocked on *k*:
in case either:
1. *k* exists AND the *k* type matches the current client blocking type
OR
2. *k* exists and *c* is blocked on module command
OR
3. *k* does not exists and *c* was blocked with the flag
unblock_on_deleted_key
do:
1. remove the client from the list of clients blocked on this key
2. remove the blocking list node from the client blocking key dict
3. remove the client from the timeout list
10. queue the client on the unblocked_clients list
11. *NEW*: call processCommandAndResetClient(c);
```
*NOTE:* for module blocked clients we will still call the moduleUnblockClientByHandle
which will queue the client for processing in moduleUnblockedClients list.
**Process Unblocked clients**
---------------------------------------------------
The process of all unblocked clients is done in the beforeSleep and no change is planned
in that part.
The general schema will be:
For each client *c* in server.unblocked_clients:
* remove client from the server.unblocked_clients
* set back the client readHandler
* continue processing the pending command and input buffer.
*Some notes regarding the new implementation*
---------------------------------------------------
1. Although it was proposed, it is currently difficult to remove the
read handler from the client while it is blocked.
The reason is that a blocked client should be unblocked when it is
disconnected, or we might consume data into void.
2. While this PR mainly keep the current blocking logic as-is, there
might be some future additions to the infrastructure that we would
like to have:
- allow non-preemptive blocking of client - sometimes we can think
that a new kind of blocking can be expected to not be preempt. for
example lets imagine we hold some keys on disk and when a command
needs to process them it will block until the keys are uploaded.
in this case we will want the client to not disconnect or be
unblocked until the process is completed (remove the client read
handler, prevent client timeout, disable unblock via debug command etc...).
- allow generic blocking based on command declared keys - we might
want to add a hook before command processing to check if any of the
declared keys require the command to block. this way it would be
easier to add new kinds of key-based blocking mechanisms.
Co-authored-by: Oran Agra <oran@redislabs.com>
Signed-off-by: Ran Shidlansik <ranshid@amazon.com>
From https://en.wikipedia.org/wiki/NaN#Display, it says
that apart from nan and -nan, we can also get NAN and even
nan(char-sequence) from libc.
In #11482, our conclusion was that we wanna normalize it in
Redis to a single nan type, like we already normalized inf.
For this, we also reverted the assert_match part of the test
added in #11506, using assert_equal to validate the changes.
## Issue
During the client input/output buffer processing, the memory usage is
incrementally updated to keep track of clients going beyond a certain
threshold `maxmemory-clients` to be evicted. However, this additional
tracking activity leads to unnecessary CPU cycles wasted when no
client-eviction is required. It is applicable in two cases.
* `maxmemory-clients` is set to `0` which equates to no client eviction
(applicable to all clients)
* `CLIENT NO-EVICT` flag is set to `ON` which equates to a particular
client not applicable for eviction.
## Solution
* Disable client memory usage tracking during the read/write flow when
`maxmemory-clients` is set to `0` or `client no-evict` is `on`.
The memory usage is tracked only during the `clientCron` i.e. it gets
periodically updated.
* Cleanup the clients from the memory usage bucket when client eviction
is disabled.
* When the maxmemory-clients config is enabled or disabled at runtime,
we immediately update the memory usage buckets for all clients (tested
scanning 80000 took some 20ms)
Benchmark shown that this can improve performance by about 5% in
certain situations.
Co-authored-by: Oran Agra <oran@redislabs.com>
As being discussed in #10981 we see a degradation in performance
between v6.2 and v7.0 of Redis on the EVAL command.
After profiling the current unstable branch we can see that we call the
expensive function evalCalcFunctionName twice.
The current "fix" is to basically avoid calling evalCalcFunctionName and
even dictFind(lua_scripts) twice for the same command.
Instead we cache the current script's dictEntry (for both Eval and Functions)
in the current client so we don't have to repeat these calls.
The exception would be when doing an EVAL on a new script that's not yet
in the script cache. in that case we will call evalCalcFunctionName (and even
evalExtractShebangFlags) twice.
Co-authored-by: Oran Agra <oran@redislabs.com>
Introduce socket `shutdown()` into connection type, and use it
on normal socket if a fork is active. This allows us to close
client connections when there are child processes sharing the
file descriptors.
Fixes#10077. The reason is that since the `fork()` child is holding
the file descriptors, the `close` in `unlinkClient -> connClose`
isn't sufficient. The client will not realize that the connection is
disconnected until the child process ends.
Let's try to be conservative and only use shutdown when the fork is active.
Renamed from "Pause Clients" to "Pause Actions" since the mechanism can pause
several actions in redis, not just clients (e.g. eviction, expiration).
Previously each pause purpose (which has a timeout that's tracked separately from others purposes),
also implicitly dictated what it pauses (reads, writes, eviction, etc). Now it is explicit, and
the actions that are paused (bit flags) are defined separately from the purpose.
- Previously, when using feature pause-client it also implicitly means to make the server static:
- Pause replica traffic
- Pauses eviction processing
- Pauses expire processing
Making the server static is used also for failover and shutdown. This PR internally rebrand
pause-client API to become pause-action API. It also Simplifies pauseClients structure
by replacing pointers array with static array.
The context of this PR is to add another trigger to pause-client which will activated in case
of OOM as throttling mechanism ([see here](https://github.com/redis/redis/issues/10907)).
In this case we want only to pause client, and eviction actions.
* Fixes build warning when CACHE_LINE_SIZE is already defined
* Fixes wrong CACHE_LINE_SIZE on some FreeBSD systems where it could be set to 128 (e.g. on MIPS)
* Fixes wrong CACHE_LINE_SIZE on Apple M1 (use 128 instead of 64)
Wrong cache line size in that case can some false sharing of array elements between threads, see #10892
Pieter Cailliau