- 29 Mar, 2023 1 commit
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Itamar Haber authored
This is an attempt to normalize/formalize command summaries. Main actions performed: * Starts with the continuation of the phrase "The XXXX command, when called, ..." for user commands. * Starts with "An internal command...", "A container command...", etc... when applicable. * Always uses periods. * Refrains from referring to other commands. If this is needed, backquotes should be used for command names. * Tries to be very clear about the data type when applicable. * Tries to mention additional effects, e.g. "The key is created if it doesn't exist" and "The set is deleted if the last member is removed." * Prefers being terse over verbose. * Tries to be consistent.
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- 11 Mar, 2023 1 commit
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guybe7 authored
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...
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- 09 Mar, 2022 1 commit
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Oran Agra authored
* stats and latency commands have non-deterministic output. * the ones about latency should be sent to ALL_NODES (considering reads from replicas) * the ones about running scripts and memory usage only to masters. * stats aggregation is SPECIAL (like in INFO)
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- 05 Jan, 2022 1 commit
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filipe oliveira authored
Added INFO LATENCYSTATS section: latency by percentile distribution/latency by cumulative distribution of latencies (#9462) # Short description The Redis extended latency stats track per command latencies and enables: - exporting the per-command percentile distribution via the `INFO LATENCYSTATS` command. **( percentile distribution is not mergeable between cluster nodes ).** - exporting the per-command cumulative latency distributions via the `LATENCY HISTOGRAM` command. Using the cumulative distribution of latencies we can merge several stats from different cluster nodes to calculate aggregate metrics . By default, the extended latency monitoring is enabled since the overhead of keeping track of the command latency is very small. If you don't want to track extended latency metrics, you can easily disable it at runtime using the command: - `CONFIG SET latency-tracking no` By default, the exported latency percentiles are the p50, p99, and p999. You can alter them at runtime using the command: - `CONFIG SET latency-tracking-info-percentiles "0.0 50.0 100.0"` ## Some details: - The total size per histogram should sit around 40 KiB. We only allocate those 40KiB when a command was called for the first time. - With regards to the WRITE overhead As seen below, there is no measurable overhead on the achievable ops/sec or full latency spectrum on the client. Including also the measured redis-benchmark for unstable vs this branch. - We track from 1 nanosecond to 1 second ( everything above 1 second is considered +Inf ) ## `INFO LATENCYSTATS` exposition format - Format: `latency_percentiles_usec_<CMDNAME>:p0=XX,p50....` ## `LATENCY HISTOGRAM [command ...]` exposition format Return a cumulative distribution of latencies in the format of a histogram for the specified command names. The histogram is composed of a map of time buckets: - Each representing a latency range, between 1 nanosecond and roughly 1 second. - Each bucket covers twice the previous bucket's range. - Empty buckets are not printed. - Everything above 1 sec is considered +Inf. - At max there will be log2(1000000000)=30 buckets We reply a map for each command in the format: `<command name> : { `calls`: <total command calls> , `histogram` : { <bucket 1> : latency , < bucket 2> : latency, ... } }` Co-authored-by:
Oran Agra <oran@redislabs.com>
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- 15 Dec, 2021 1 commit
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guybe7 authored
Delete the hardcoded command table and replace it with an auto-generated table, based on a JSON file that describes the commands (each command must have a JSON file). These JSON files are the SSOT of everything there is to know about Redis commands, and it is reflected fully in COMMAND INFO. These JSON files are used to generate commands.c (using a python script), which is then committed to the repo and compiled. The purpose is: * Clients and proxies will be able to get much more info from redis, instead of relying on hard coded logic. * drop the dependency between Redis-user and the commands.json in redis-doc. * delete help.h and have redis-cli learn everything it needs to know just by issuing COMMAND (will be done in a separate PR) * redis.io should stop using commands.json and learn everything from Redis (ultimately one of the release artifacts should be a large JSON, containing all the information about all of the commands, ...
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