- 27 Oct, 2022 1 commit
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Moti Cohen authored
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.
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- 16 Oct, 2022 1 commit
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David CARLIER authored
* 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
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- 15 Oct, 2022 1 commit
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filipe oliveira authored
optimizing d2string() and addReplyDouble() with grisu2: double to string conversion based on Florian Loitsch's Grisu-algorithm (#10587) All commands / use cases that heavily rely on double to a string representation conversion, (e.g. meaning take a double-precision floating-point number like 1.5 and return a string like "1.5" ), could benefit from a performance boost by swapping snprintf(buf,len,"%.17g",value) by the equivalent [fpconv_dtoa](https://github.com/night-shift/fpconv) or any other algorithm that ensures 100% coverage of conversion. This is a well-studied topic and Projects like MongoDB. RedPanda, PyTorch leverage libraries ( fmtlib ) that use the optimized double to string conversion underneath. The positive impact can be substantial. This PR uses the grisu2 approach ( grisu explained on https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf section 5 ). test suite changes: Despite being compatible, in some cases it produces a different result from printf, and some tests had to be adjusted. one case is that `%.17g` (which means %e or %f which ever is shorter), chose to use `5000000000` instead of 5e+9, which sounds like a bug? In other cases, we changed TCL to compare numbers instead of strings to ignore minor rounding issues (`expr 0.8 == 0.79999999999999999`)
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- 22 Sep, 2022 1 commit
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Shaya Potter authored
Adds a number of user management/ACL validaiton/command execution functions to improve a Redis module's ability to enforce ACLs correctly and easily. * RM_SetContextUser - sets a RedisModuleUser on the context, which RM_Call will use to both validate ACLs (if requested and set) as well as assign to the client so that scripts executed via RM_Call will have proper ACL validation. * RM_SetModuleUserACLString - Enables one to pass an entire ACL string, not just a single OP and have it applied to the user * RM_GetModuleUserACLString - returns a stringified version of the user's ACL (same format as dump and list). Contains an optimization to cache the stringified version until the underlying ACL is modified. * Slightly re-purpose the "C" flag to RM_Call from just being about ACL check before calling the command, to actually running the command with the right user, so that it also affects commands inside EVAL scripts. see #11231
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- 15 Sep, 2022 1 commit
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Adi Pinsky authored
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- 26 Aug, 2022 1 commit
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Paul Menzel authored
networking: Spell verb *set up* with space in error message
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- 23 Aug, 2022 1 commit
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Ariel Shtul authored
The previous implementation calls `snprintf` twice, the second time used to 'memcpy' the output of the first, which could be a very large string. The new implementation reserves space for the protocol header ahead of the formatted double, and then prepends the string length ahead of it. Measured improvement of simple ZADD of some 25%.
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- 22 Aug, 2022 4 commits
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zhenwei pi authored
Unix socket uses different accept handler/create listener from TCP, to hide these difference to avoid hard code, use a new unix socket connection type. Also move 'acceptUnixHandler' into unix.c. Currently, the connection framework becomes like following: uplayer | connection layer / | \ TCP Unix TLS It's possible to build Unix socket support as a shared library, and load it dynamically. Because TCP and Unix socket don't require any heavy dependencies or overheads, we build them into Redis statically. Signed-off-by:
zhenwei pi <pizhenwei@bytedance.com>
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zhenwei pi authored
Abstract accept handler for socket&TLS, and add helper function 'connAcceptHandler' to get accept handler by specified type. Also move acceptTcpHandler into socket.c, and move acceptTLSHandler into tls.c. Signed-off-by:
zhenwei pi <pizhenwei@bytedance.com>
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zhenwei pi authored
Abstract common interface of connection type, so Redis can hide the implementation and uplayer only calls connection API without macro. uplayer | connection layer / \ socket TLS Currently, for both socket and TLS, all the methods of connection type are declared as static functions. It's possible to build TLS(even socket) as a shared library, and Redis loads it dynamically in the next step. Also add helper function connTypeOfCluster() and connTypeOfReplication() to simplify the code: link->conn = server.tls_cluster ? connCreateTLS() : connCreateSocket(); -> link->conn = connCreate(connTypeOfCluster()); Signed-off-by:
zhenwei pi <pizhenwei@bytedance.com>
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zhenwei pi authored
Originally, connPeerToString is designed to get the address info from socket only(for both TCP & TLS), and the API 'connPeerToString' is oriented to operate a FD like: int connPeerToString(connection *conn, char *ip, size_t ip_len, int *port) { return anetFdToString(conn ? conn->fd : -1, ip, ip_len, port, FD_TO_PEER_NAME); } Introduce connAddr and implement .addr method for socket and TLS, thus the API 'connAddr' and 'connFormatAddr' become oriented to a connection like: static inline int connAddr(connection *conn, char *ip, size_t ip_len, int *port, int remote) { if (conn && conn->type->addr) { return conn->type->addr(conn, ip, ip_len, port, remote); } return -1; } Also remove 'FD_TO_PEER_NAME' & 'FD_TO_SOCK_NAME', use a boolean type 'remote' to get local/remote address of a connection. With these changes, it's possible to support the other connection types which does not use socket(Ex, RDMA). Thanks to Oran for suggestions! Signed-off-by:
zhenwei pi <pizhenwei@bytedance.com>
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- 04 Aug, 2022 1 commit
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filipe oliveira authored
Avoid the sdslen() on shared.crlf given we know its size beforehand. Improve ~3-4% of cpu cycles to lrange logic (#10987) * Avoid the sdslen() on shared.crlf given we know its size beforehand * Removed shared.crlf from sharedObjects
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- 18 Jul, 2022 1 commit
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ranshid authored
replace use of: sprintf --> snprintf strcpy/strncpy --> redis_strlcpy strcat/strncat --> redis_strlcat **why are we making this change?** Much of the code uses some unsafe variants or deprecated buffer handling functions. While most cases are probably not presenting any issue on the known path programming errors and unterminated strings might lead to potential buffer overflows which are not covered by tests. **As part of this PR we change** 1. added implementation for redis_strlcpy and redis_strlcat based on the strl implementation: https://linux.die.net/man/3/strl 2. change all occurrences of use of sprintf with use of snprintf 3. change occurrences of use of strcpy/strncpy with redis_strlcpy 4. change occurrences of use of strcat/strncat with redis_strlcat 5. change the behavior of ll2string/ull2string/ld2string so that it will always place null termination ('\0') on the output buffer in the first index. this was done in order to make the use of these functions more safe in cases were the user will not check the output returned by them (for example in rdbRemoveTempFile) 6. we added a compiler directive to issue a deprecation error in case a use of sprintf/strcpy/strcat is found during compilation which will result in error during compile time. However keep in mind that since the deprecation attribute is not supported on all compilers, this is expected to fail during push workflows. **NOTE:** while this is only an initial milestone. We might also consider using the *_s implementation provided by the C11 Extensions (however not yet widly supported). I would also suggest to start looking at static code analyzers to track unsafe use cases. For example LLVM clang checker supports security.insecureAPI.DeprecatedOrUnsafeBufferHandling which can help locate unsafe function usage. https://clang.llvm.org/docs/analyzer/checkers.html#security-insecureapi-deprecatedorunsafebufferhandling-c The main reason not to onboard it at this stage is that the alternative excepted by clang is to use the C11 extensions which are not always supported by stdlib.
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- 12 Jul, 2022 1 commit
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Wen Hui authored
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- 04 Jul, 2022 1 commit
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Harkrishn Patro authored
Account sharded pubsub channels memory consumption in client memory usage computation to accurately evict client based on the set threshold for `maxmemory-clients`.
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- 28 Jun, 2022 1 commit
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jonnyomerredis authored
When calling CLIENT INFO/LIST, and in various debug prints, Redis is printing the number of pubsub channels / patterns the client is subscribed to. With the addition of sharded pubsub, it would be useful to print the number of keychannels the client is subscribed to as well.
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- 26 Jun, 2022 2 commits
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Viktor Söderqvist authored
Adding Module APIs to let the module read and set the client name of an arbitrary connection.
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Elvina Yakubova authored
There are a lot of false sharing cache misses in line 4013 inside getIOPendingCount function. The reason is that elements of io_threads_pending array access the same cache line from different threads, so it is better to represent it as an array of structures with fields aligned to cache line size. This change should improve performance (in particular, it affects the latency metric, we saw up to 3% improvement).
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- 01 Jun, 2022 1 commit
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Oran Agra authored
Fix broken protocol in MISCONF error, RM_Yield bugs, RM_Call(EVAL) OOM check bug, and new RM_Call checks. (#10786) * Fix broken protocol when redis can't persist to RDB (general commands, not modules), excessive newline. regression of #10372 (7.0 RC3) * Fix broken protocol when Redis can't persist to AOF (modules and scripts), missing newline. * Fix bug in OOM check of EVAL scripts called from RM_Call. set the cached OOM state for scripts before executing module commands too, so that it can serve scripts that are executed by modules. i.e. in the past EVAL executed by RM_Call could have either falsely fail or falsely succeeded because of a wrong cached OOM state flag. * Fix bugs with RM_Yield: 1. SHUTDOWN should only accept the NOSAVE mode 2. Avoid eviction during yield command processing. 3. Avoid processing master client commands while yielding from another client * Add new two more checks to RM_Call script mode. 1. READONLY You can't write against a read only replica 2. MASTERDOWN Link with MASTER is down and `replica-serve-stale-data` is set to `no` * Add new RM_Call flag to let redis automatically refuse `deny-oom` commands while over the memory limit. * Add tests to cover various errors from Scripts, Modules, Modules calling scripts, and Modules calling commands in script mode. Add tests: * Looks like the MISCONF error was completely uncovered by the tests, add tests for it, including from scripts, and modules * Add tests for NOREPLICAS from scripts * Add tests for the various errors in module RM_Call, including RM_Call that calls EVAL, and RM_call in "eval mode". that includes: NOREPLICAS, READONLY, MASTERDOWN, MISCONF
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- 31 May, 2022 1 commit
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DarrenJiang13 authored
The amount of `server.stat_net_output_bytes/server.stat_net_input_bytes` is actually the sum of replication flow and users' data flow. It may cause confusions like this: "Why does my server get such a large output_bytes while I am doing nothing? ". After discussions and revisions, now here is the change about what this PR brings (final version before merge): - 2 server variables to count the network bytes during replication, including fullsync and propagate bytes. - `server.stat_net_repl_output_bytes`/`server.stat_net_repl_input_bytes` - 3 info fields to print the input and output of repl bytes and instantaneous value of total repl bytes. - `total_net_repl_input_bytes` / `total_net_repl_output_bytes` - `instantaneous_repl_total_kbps` - 1 new API `rioCheckType()` to check the type of rio. So we can use this to distinguish between diskless and diskbased replication - 2 new counting items to keep network statistics consistent between master and slave - rdb portion during diskless replica. in `rdbLoadProgressCallback()` - first line of the full sync payload. in `readSyncBulkPayload()` Co-authored-by:
Oran Agra <oran@redislabs.com>
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- 15 May, 2022 1 commit
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Tian authored
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- 26 Apr, 2022 2 commits
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Madelyn Olson authored
* Till now, replicas that were unable to persist, would still execute the commands they got from the master, now they'll panic by default, and we add a new `replica-ignore-disk-errors` config to change that. * Till now, when a command failed on a replica or AOF-loading, it only logged a warning and a stat, we add a new `propagation-error-behavior` config to allow panicking in that state (may become the default one day) Note that commands that fail on the replica can either indicate a bug that could cause data inconsistency between the replica and the master, or they could be in some cases (specifically in previous versions), a result of a command (e.g. EVAL) that failed on the master, but still had to be propagated to fail on the replica as well.
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Madelyn Olson authored
Adds the `allow-cross-slot-keys` flag to Eval scripts and Functions to allow scripts to access keys from multiple slots. The default behavior is now that they are not allowed to do that (unlike before). This is a breaking change for 7.0 release candidates (to be part of 7.0.0), but not for previous redis releases since EVAL without shebang isn't doing this check. Note that the check is done on both the keys declared by the EVAL / FCALL command arguments, and also the ones used by the script when making a `redis.call`. A note about the implementation, there seems to have been some confusion about allowing access to non local keys. I thought I missed something in our wider conversation, but Redis scripts do block access to non-local keys. So the issue was just about cross slots being accessed.
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- 25 Apr, 2022 2 commits
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Binbin authored
minor cleanup for recent changes.
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guybe7 authored
1. Disk error and slave count checks didn't flag the transactions or counted correctly in command stats (regression from #10372 , 7.0 RC3) 2. RM_Call will reply the same way Redis does, in case of non-exisitng command or arity error 3. RM_WrongArtiy will consider the full command name 4. Use lowercase 'u' in "unknonw subcommand" (to align with "unknown command") Followup work of #10127
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- 11 Apr, 2022 1 commit
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zhaozhao.zz authored
Durability of database is a big and old topic, in this regard Redis use AOF to support it, and `appendfsync=alwasys` policy is the most strict level, guarantee all data is both written and synced on disk before reply success to client. But there are some cases have been overlooked, and could lead to durability broken. 1. The most clear one is about threaded-io mode we should also set client's write handler with `ae_barrier` in `handleClientsWithPendingWritesUsingThreads`, or the write handler would be called after read handler in the next event loop, it means the write command result could be replied to client before flush to AOF. 2. About blocked client (mostly by module) in `beforeSleep()`, `handleClientsBlockedOnKeys()` should be called before `flushAppendOnlyFile()`, in case the unblocked clients modify data without persistence but send reply. 3. When handling `ProcessingEventsWhileBlocked` normally it takes place when lua/function/module timeout, and we give a chance to users to kill the slow operation, but we should call `flushAppendOnlyFile()` before `handleClientsWithPendingWrites()`, in case the other clients in the last event loop get acknowledge before data persistence. for a instance: ``` in the same event loop client A executes set foo bar client B executes eval "for var=1,10000000,1 do end" 0 ``` after the script timeout, client A will get `OK` but lose data after restart (kill redis when timeout) if we don't flush the write command to AOF. 4. A more complex case about `ProcessingEventsWhileBlocked` it is lua timeout in transaction, for example `MULTI; set foo bar; eval "for var=1,10000000,1 do end" 0; EXEC`, then client will get set command's result before the whole transaction done, that breaks atomicity too. fortunately, it's already fixed by #5428 (although it's not the original purpose just a side effect : )), but module timeout should be fixed too. case 1, 2, 3 are fixed in this commit, the module issue in case 4 needs a followup PR.
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- 10 Apr, 2022 1 commit
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cyhone authored
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- 25 Mar, 2022 1 commit
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zhaozhao.zz authored
To remove `pending_querybuf`, the key point is reusing `querybuf`, it means master client's `querybuf` is not only used to parse command, but also proxy to sub-replicas. 1. add a new variable `repl_applied` for master client to record how many data applied (propagated via `replicationFeedStreamFromMasterStream()`) but not trimmed in `querybuf`. 2. don't sdsrange `querybuf` in `commandProcessed()`, we trim it to `repl_applied` after the whole replication pipeline processed to avoid fragmented `sdsrange`. And here are some scenarios we cannot trim to `qb_pos`: * we don't receive complete command from master * master client blocked because of client pause * IO threads operate read, master client flagged with CLIENT_PENDING_COMMAND In these scenarios, `qb_pos` points to the part of the current command or the beginning of next command, and the current command is not applied yet, so the `repl_applied` is not equal to `qb_pos`. Some other notes: * Do not do big arg optimization on master client, since we can only sdsrange `querybuf` after data sent to replicas. * Set `qb_pos` and `repl_applied` to 0 when `freeClient` in `replicationCacheMaster`. * Rewrite `processPendingCommandsAndResetClient` to `processPendingCommandAndInputBuffer`, let `processInputBuffer` to be called successively after `processCommandAndResetClient`.
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- 16 Mar, 2022 1 commit
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Madelyn Olson authored
Add module API for redacting client commands
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- 15 Mar, 2022 1 commit
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yoav-steinberg authored
In a benchmark we noticed we spend a relatively long time updating the client memory usage leading to performance degradation. Before #8687 this was performed in the client's cron and didn't affect performance. But since introducing client eviction we need to perform this after filling the input buffers and after processing commands. This also lead me to write this code to be thread safe and perform it in the i/o threads. It turns out that the main performance issue here is related to atomic operations being performed while updating the total clients memory usage stats used for client eviction (`server.stat_clients_type_memory[]`). This update needed to be atomic because `updateClientMemUsage()` was called from the IO threads. In this commit I make sure to call `updateClientMemUsage()` only from the main thread. In case of threaded IO I call it for each client during the "fan-in" phase of the read/write operation. This also means I could chuck the `updateClientMemUsageBucket()` function which was called during this phase and embed it into `updateClientMemUsage()`. Profiling shows this makes `updateClientMemUsage()` (on my x86_64 linux) roughly x4 faster.
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- 13 Mar, 2022 1 commit
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Wen Hui authored
probably a copy paste error.
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- 09 Mar, 2022 1 commit
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a2tt authored
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- 08 Mar, 2022 1 commit
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guybe7 authored
Deleting a stream while a client is blocked XREADGROUP should unblock the client. The idea is that if a client is blocked via XREADGROUP is different from any other blocking type in the sense that it depends on the existence of both the key and the group. Even if the key is deleted and then revived with XADD it won't help any clients blocked on XREADGROUP because the group no longer exist, so they would fail with -NOGROUP anyway. The conclusion is that it's better to unblock these clients (with error) upon the deletion of the key, rather than waiting for the first XADD. Other changes: 1. Slightly optimize all `serveClientsBlockedOn*` functions by checking `server.blocked_clients_by_type` 2. All `serveClientsBlockedOn*` functions now use a list iterator rather than looking at `listFirst`, relying on `unblockClient` to delete the head of the list. Before this commit, only `serveClientsBlockedOnStreams` used to work like that. 3. bugfix: CLIENT UNBLOCK ERROR should work even if the command doesn't have a timeout_callback (only relevant to module commands)
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- 27 Feb, 2022 1 commit
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Meir Shpilraien (Spielrein) authored
This PR fix 2 issues on Lua scripting: * Server error reply statistics (some errors were counted twice). * Error code and error strings returning from scripts (error code was missing / misplaced). ## Statistics a Lua script user is considered part of the user application, a sophisticated transaction, so we want to count an error even if handled silently by the script, but when it is propagated outwards from the script we don't wanna count it twice. on the other hand, if the script decides to throw an error on its own (using `redis.error_reply`), we wanna count that too. Besides, we do count the `calls` in command statistics for the commands the script calls, we we should certainly also count `failed_calls`. So when a simple `eval "return redis.call('set','x','y')" 0` fails, it should count the failed call to both SET and EVAL, but the `errorstats` and `total_error_replies` should be counted only once. The PR changes the error object that is raised on errors. Instead of raising a simple Lua string, Redis will raise a Lua table in the following format: ``` { err='<error message (including error code)>', source='<User source file name>', line='<line where the error happned>', ignore_error_stats_update=true/false, } ``` The `luaPushError` function was modified to construct the new error table as describe above. The `luaRaiseError` was renamed to `luaError` and is now simply called `lua_error` to raise the table on the top of the Lua stack as the error object. The reason is that since its functionality is changed, in case some Redis branch / fork uses it, it's better to have a compilation error than a bug. The `source` and `line` fields are enriched by the error handler (if possible) and the `ignore_error_stats_update` is optional and if its not present then the default value is `false`. If `ignore_error_stats_update` is true, the error will not be counted on the error stats. When parsing Redis call reply, each error is translated to a Lua table on the format describe above and the `ignore_error_stats_update` field is set to `true` so we will not count errors twice (we counted this error when we invoke the command). The changes in this PR might have been considered as a breaking change for users that used Lua `pcall` function. Before, the error was a string and now its a table. To keep backward comparability the PR override the `pcall` implementation and extract the error message from the error table and return it. Example of the error stats update: ``` 127.0.0.1:6379> lpush l 1 (integer) 2 127.0.0.1:6379> eval "return redis.call('get', 'l')" 0 (error) WRONGTYPE Operation against a key holding the wrong kind of value. script: e471b73f1ef44774987ab00bdf51f21fd9f7974a, on @user_script:1. 127.0.0.1:6379> info Errorstats # Errorstats errorstat_WRONGTYPE:count=1 127.0.0.1:6379> info commandstats # Commandstats cmdstat_eval:calls=1,usec=341,usec_per_call=341.00,rejected_calls=0,failed_calls=1 cmdstat_info:calls=1,usec=35,usec_per_call=35.00,rejected_calls=0,failed_calls=0 cmdstat_lpush:calls=1,usec=14,usec_per_call=14.00,rejected_calls=0,failed_calls=0 cmdstat_get:calls=1,usec=10,usec_per_call=10.00,rejected_calls=0,failed_calls=1 ``` ## error message We can now construct the error message (sent as a reply to the user) from the error table, so this solves issues where the error message was malformed and the error code appeared in the middle of the error message: ```diff 127.0.0.1:6379> eval "return redis.call('set','x','y')" 0 -(error) ERR Error running script (call to 71e6319f97b0fe8bdfa1c5df3ce4489946dda479): @user_script:1: OOM command not allowed when used memory > 'maxmemory'. +(error) OOM command not allowed when used memory > 'maxmemory' @user_script:1. Error running script (call to 71e6319f97b0fe8bdfa1c5df3ce4489946dda479) ``` ```diff 127.0.0.1:6379> eval "redis.call('get', 'l')" 0 -(error) ERR Error running script (call to f_8a705cfb9fb09515bfe57ca2bd84a5caee2cbbd1): @user_script:1: WRONGTYPE Operation against a key holding the wrong kind of value +(error) WRONGTYPE Operation against a key holding the wrong kind of value script: 8a705cfb9fb09515bfe57ca2bd84a5caee2cbbd1, on @user_script:1. ``` Notica that `redis.pcall` was not change: ``` 127.0.0.1:6379> eval "return redis.pcall('get', 'l')" 0 (error) WRONGTYPE Operation against a key holding the wrong kind of value ``` ## other notes Notice that Some commands (like GEOADD) changes the cmd variable on the client stats so we can not count on it to update the command stats. In order to be able to update those stats correctly we needed to promote `realcmd` variable to be located on the client struct. Tests was added and modified to verify the changes. Related PR's: #10279, #10218, #10278, #10309 Co-authored-by:
Oran Agra <oran@redislabs.com>
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- 24 Feb, 2022 1 commit
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filipe oliveira authored
Avoid deferred array reply on genericZrangebyrankCommand() when consumer type is client. I.e. any ZRANGE / ZREVRNGE (when tank is used). This was a performance regression introduced in #7844 (v 6.2) mainly affecting pipelined workloads. Co-authored-by:
Oran Agra <oran@redislabs.com>
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- 23 Feb, 2022 1 commit
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filipe oliveira authored
Avoid sprintf/ll2string on setDeferredAggregateLen()/addReplyLongLongWithPrefix() when we can used shared objects. In some pipelined workloads this achieves about 10% improvement. Co-authored-by:
Oran Agra <oran@redislabs.com>
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- 22 Feb, 2022 2 commits
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Andy Pan authored
There are scenarios where it results in many small objects in the reply list, such as commands heavily using deferred array replies (`addReplyDeferredLen`). E.g. what COMMAND command and CLUSTER SLOTS used to do (see #10056, #7123), but also in case of a transaction or a pipeline of commands that use just one differed array reply. We used to have to run multiple loops along with multiple calls to `write()` to send data back to peer based on the current code, but by means of `writev()`, we can gather those scattered objects in reply list and include the static reply buffer as well, then send it by one system call, that ought to achieve higher performance. In the case of TLS, we simply check and concatenate buffers into one big buffer and send it away by one call to `connTLSWrite()`, if the amount of all buffers exceeds `NET_MAX_WRITES_PER_EVENT`, then invoke `connTLSWrite()` multiple times to avoid a huge massive of memory copies. Note that aside of reducing system calls, this change will also reduce the amount of small TCP packets sent.
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ranshid authored
Current implementation simple idle client which serves no traffic still use ~17Kb of memory. this is mainly due to a fixed size reply buffer currently set to 16kb. We have encountered some cases in which the server operates in a low memory environments. In such cases a user who wishes to create large connection pools to support potential burst period, will exhaust a large amount of memory to maintain connected Idle clients. Some users may choose to "sacrifice" performance in order to save memory. This commit introduce a dynamic mechanism to shrink and expend the client reply buffer based on periodic observed peak. the algorithm works as follows: 1. each time a client reply buffer has been fully written, the last recorded peak is updated: new peak = MAX( last peak, current written size) 2. during clients cron we check for each client if the last observed peak was: a. matching the current buffer size - in which case we expend (resize) the buffer size by 100% b. less than half the buffer size - in which case we shrink the buffer size by 50% 3. In any case we will **not** resize the buffer in case: a. the current buffer peak is less then the current buffer usable size and higher than 1/2 the current buffer usable size b. the value of (current buffer usable size/2) is less than 1Kib c. the value of (current buffer usable size*2) is larger than 16Kib 4. the peak value is reset to the current buffer position once every **5** seconds. we maintain a new field in the client structure (buf_peak_last_reset_time) which is used to keep track of how long it passed since the last buffer peak reset. ### **Interface changes:** **CIENT LIST** - now contains 2 new extra fields: rbs= < the current size in bytes of the client reply buffer > rbp=< the current value in bytes of the last observed buffer peak position > **INFO STATS** - now contains 2 new statistics: reply_buffer_shrinks = < total number of buffer shrinks performed > reply_buffer_expends = < total number of buffer expends performed > Co-authored-by:
Oran Agra <oran@redislabs.com> Co-authored-by:
Yoav Steinberg <yoav@redislabs.com>
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- 21 Feb, 2022 1 commit
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Oran Agra authored
This is a followup work for #10278, and a discussion about #10279 The changes: - fix failed_calls in command stats for blocked clients that got error. including CLIENT UNBLOCK, and module replying an error from a thread. - fix latency stats for XREADGROUP that filed with -NOGROUP Theory behind which errors should be counted: - error stats represents errors returned to the user, so an error handled by a module should not be counted. - total error counter should be the same. - command stats represents execution of commands (even with RM_Call, and if they fail or get rejected it counts these calls in commandstats, so it should also count failed_calls) Some thoughts about Scripts: for scripts it could be different since they're part of user code, not the infra (not an extension to redis) we certainly want commandstats to contain all calls and errors a simple script is like mult-exec transaction so an error inside it should be counted in error stats a script that replies with an error to the user (using redis.error_reply) should also be counted in error stats but then the problem is that a plain `return redis.call("SET")` should not be counted twice (once for the SET and once for EVAL) so that's something left to be resolved in #10279
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- 13 Feb, 2022 1 commit
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Oran Agra authored
This PR handles several aspects 1. Calls to RM_ReplyWithError from thread safe contexts don't violate thread safety. 2. Errors returning from RM_Call to the module aren't counted in the statistics (they might be handled silently by the module) 3. When a module propagates a reply it got from RM_Call to it's client, then the error statistics are counted. This is done by: 1. When appending an error reply to the output buffer, we avoid updating the global error statistics, instead we cache that error in a deferred list in the client struct. 2. When creating a RedisModuleCallReply object, the deferred error list is moved from the client into that object. 3. when a module calls RM_ReplyWithCallReply we copy the deferred replies to the dest client (if that's a real client, then that's when the error statistics are updated to the server) Note about RM_ReplyWithCallReply: if the original reply had an array with errors, and the module replied with just a portion of the original reply, and not the entire reply, the errors are currently not propagated and the errors stats will not get propagated. Fix #10180
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