- 07 Jun, 2022 1 commit
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Bjorn Svensson authored
Correcting the introduction version of the command `BITFIELD_RO` Command added by commit: b3e4abf0 Add history info of the `FULL` modifier in `XINFO STREAM` Modifier was added by commit: 1e2aee39 (Includes output from `./utils/generate-command-code.py`)
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- 23 Feb, 2022 1 commit
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Itamar Haber authored
Adds the ability to track the lag of a consumer group (CG), that is, the number of entries yet-to-be-delivered from the stream. The proposed constant-time solution is in the spirit of "best-effort." Partially addresses #8737. ## Description of approach We add a new "entries_added" property to the stream. This starts at 0 for a new stream and is incremented by 1 with every `XADD`. It is essentially an all-time counter of the entries added to the stream. Given the stream's length and this counter value, we can trivially find the logical "entries_added" counter of the first ID if and only if the stream is contiguous. A fragmented stream contains one or more tombstones generated by `XDEL`s. The new "xdel_max_id" stream property tracks the latest tombstone. The CG also tracks its last delivered ID's as an "entries_read" counter and increments it independently when delivering new messages, unless the this read counter is invalid (-1 means invalid offset). When the CG's counter is available, the reported lag is the difference between added and read counters. Lastly, this also adds a "first_id" field to the stream structure in order to make looking it up cheaper in most cases. ## Limitations There are two cases in which the mechanism isn't able to track the lag. In these cases, `XINFO` replies with `null` in the "lag" field. The first case is when a CG is created with an arbitrary last delivered ID, that isn't "0-0", nor the first or the last entries of the stream. In this case, it is impossible to obtain a valid read counter (short of an O(N) operation). The second case is when there are one or more tombstones fragmenting the stream's entries range. In both cases, given enough time and assuming that the consumers are active (reading and lacking) and advancing, the CG should be able to catch up with the tip of the stream and report zero lag. Once that's achieved, lag tracking would resume as normal (until the next tombstone is set). ## API changes * `XGROUP CREATE` added with the optional named argument `[ENTRIESREAD entries-read]` for explicitly specifying the new CG's counter. * `XGROUP SETID` added with an optional positional argument `[ENTRIESREAD entries-read]` for specifying the CG's counter. * `XINFO` reports the maximal tombstone ID, the recorded first entry ID, and total number of entries added to the stream. * `XINFO` reports the current lag and logical read counter of CGs. * `XSETID` is an internal command that's used in replication/aof. It has been added with the optional positional arguments `[ENTRIESADDED entries-added] [MAXDELETEDID max-deleted-entry-id]` for propagating the CG's offset and maximal tombstone ID of the stream. ## The generic unsolved problem The current stream implementation doesn't provide an efficient way to obtain the approximate/exact size of a range of entries. While it could've been nice to have that ability (#5813) in general, let alone specifically in the context of CGs, the risk and complexities involved in such implementation are in all likelihood prohibitive. ## A refactoring note The `streamGetEdgeID` has been refactored to accommodate both the existing seek of any entry as well as seeking non-deleted entries (the addition of the `skip_tombstones` argument). Furthermore, this refactoring also migrated the seek logic to use the `streamIterator` (rather than `raxIterator`) that was, in turn, extended with the `skip_tombstones` Boolean struct field to control the emission of these. Co-authored-by:
Guy Benoish <guy.benoish@redislabs.com> Co-authored-by:
Oran Agra <oran@redislabs.com>
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- 18 Jan, 2022 1 commit
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Oran Agra authored
The new ACL key based permissions in #9974 require the key-specs (#8324) to have more explicit flags rather than just READ and WRITE. See discussion in #10040 This PR defines two groups of flags: One about how redis internally handles the key (mutually-exclusive). The other is about the logical operation done from the user's point of view (3 mutually exclusive write flags, and one read flag, all optional). In both groups, if we can't explicitly flag something as explicit read-only, delete-only, or insert-only, we flag it as `RW` or `UPDATE`. here's the definition from the code: ``` /* Key-spec flags * * -------------- */ /* The following refer what the command actually does with the value or metadata * of the key, and not necessarily the user data or how it affects it. * Each key-spec may must have exaclty one of these. Any operation that's not * distinctly deletion, overwrite or read-only would be marked as RW. */ #define CMD_KEY_RO (1ULL<<0) /* Read-Only - Reads the value of the key, but * doesn't necessarily returns it. */ #define CMD_KEY_RW (1ULL<<1) /* Read-Write - Modifies the data stored in the * value of the key or its metadata. */ #define CMD_KEY_OW (1ULL<<2) /* Overwrite - Overwrites the data stored in * the value of the key. */ #define CMD_KEY_RM (1ULL<<3) /* Deletes the key. */ /* The follwing refer to user data inside the value of the key, not the metadata * like LRU, type, cardinality. It refers to the logical operation on the user's * data (actual input strings / TTL), being used / returned / copied / changed, * It doesn't refer to modification or returning of metadata (like type, count, * presence of data). Any write that's not INSERT or DELETE, would be an UPADTE. * Each key-spec may have one of the writes with or without access, or none: */ #define CMD_KEY_ACCESS (1ULL<<4) /* Returns, copies or uses the user data from * the value of the key. */ #define CMD_KEY_UPDATE (1ULL<<5) /* Updates data to the value, new value may * depend on the old value. */ #define CMD_KEY_INSERT (1ULL<<6) /* Adds data to the value with no chance of, * modification or deletion of existing data. */ #define CMD_KEY_DELETE (1ULL<<7) /* Explicitly deletes some content * from the value of the key. */ ``` Unrelated changes: - generate-command-code.py is only compatible with python3 (modified the shabang) - generate-command-code.py print file on json parsing error - rename `shard_channel` key-spec flag to just `channel`. - add INCOMPLETE flag in input spec of SORT and SORT_RO
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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, which will be generated from COMMAND's reply) * the byproduct of this is: * module commands will be able to provide that info and possibly be more of a first-class citizens * in theory, one may be able to generate a redis client library for a strictly typed language, by using this info. ### Interface changes #### COMMAND INFO's reply change (and arg-less COMMAND) Before this commit the reply at index 7 contained the key-specs list and reply at index 8 contained the sub-commands list (Both unreleased). Now, reply at index 7 is a map of: - summary - short command description - since - debut version - group - command group - complexity - complexity string - doc-flags - flags used for documentation (e.g. "deprecated") - deprecated-since - if deprecated, from which version? - replaced-by - if deprecated, which command replaced it? - history - a list of (version, what-changed) tuples - hints - a list of strings, meant to provide hints for clients/proxies. see https://github.com/redis/redis/issues/9876 - arguments - an array of arguments. each element is a map, with the possibility of nesting (sub-arguments) - key-specs - an array of keys specs (already in unstable, just changed location) - subcommands - a list of sub-commands (already in unstable, just changed location) - reply-schema - will be added in the future (see https://github.com/redis/redis/issues/9845) more details on these can be found in https://github.com/redis/redis-doc/pull/1697 only the first three fields are mandatory #### API changes (unreleased API obviously) now they take RedisModuleCommand opaque pointer instead of looking up the command by name - RM_CreateSubcommand - RM_AddCommandKeySpec - RM_SetCommandKeySpecBeginSearchIndex - RM_SetCommandKeySpecBeginSearchKeyword - RM_SetCommandKeySpecFindKeysRange - RM_SetCommandKeySpecFindKeysKeynum Currently, we did not add module API to provide additional information about their commands because we couldn't agree on how the API should look like, see https://github.com/redis/redis/issues/9944 . ### Somehow related changes 1. Literals should be in uppercase while placeholder in lowercase. Now all the GEO* command will be documented with M|KM|FT|MI and can take both lowercase and uppercase ### Unrelated changes 1. Bugfix: no_madaory_keys was absent in COMMAND's reply 2. expose CMD_MODULE as "module" via COMMAND 3. have a dedicated uint64 for ACL categories (instead of having them in the same uint64 as command flags) Co-authored-by:
Itamar Haber <itamar@garantiadata.com>
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