Fix wrong dbnum showed in redis-cli after client reconnected #13411

vitahlin · 2024-07-12T15:35:52Z

When the server restarts while the CLI is connecting, the reconnection does not automatically select the previous db.
This may lead users to believe they are still in the previous db, in fact, they are in db0.

This PR will automatically reset the current dbnum and cliSelect() again when reconnecting.

Steps for reproducing bug

start server and client:

./src/redis-server
./src/redis-cli

set value in db0 and db5:

127.0.0.1:6379> set a 0
OK
127.0.0.1:6379> get a
"0"
127.0.0.1:6379> select 5
OK
127.0.0.1:6379[5]> set a 5
OK
127.0.0.1:6379[5]> get a
"5"
127.0.0.1:6379[5]>

Ctrl+C to stop server:

127.0.0.1:6379[5]> get a
Error: Server closed the connection
not connected>

restart server then in redis-cli:

not connected> get a
"0"
127.0.0.1:6379[5]> client list
id=3 addr=127.0.0.1:50856 laddr=127.0.0.1:6379 fd=10 name= age=45 idle=0 flags=N db=0 sub=0 psub=0 ssub=0 multi=-1 watch=0 qbuf=26 qbuf-free=16864 argv-mem=10 multi-mem=0 rbs=1024 rbp=0 obl=0 oll=0 omem=0 tot-mem=18730 events=r cmd=client|list user=default redir=-1 resp=2 lib-name= lib-ver=
127.0.0.1:6379[5]>

The redis-cli run command at db0 but showed db5.

Solution

redis-cli will re-select db5 after reconnected:

127.0.0.1:6379> get a
"0"
127.0.0.1:6379> select 5
OK
127.0.0.1:6379[5]> get a
"5"
127.0.0.1:6379[5]> get a
Error: Server closed the connection
not connected> get a
"5"
127.0.0.1:6379[5]>

src/redis-cli.c

Co-authored-by: debing.sun <[email protected]>

tests/integration/redis-cli.tcl

Co-authored-by: debing.sun <[email protected]>

tests/integration/redis-cli.tcl

Co-authored-by: debing.sun <[email protected]>

tests/integration/redis-cli.tcl

Co-authored-by: debing.sun <[email protected]>

tests/integration/redis-cli.tcl

Co-authored-by: debing.sun <[email protected]>

tests/integration/redis-cli.tcl

Co-authored-by: debing.sun <[email protected]>

sundb · 2024-08-01T23:44:39Z

@vitahlin please have a look the failure: https://github.com/sundb/redis/actions/runs/10207316287/job/28241980209

vitahlin · 2024-08-02T06:46:14Z

@vitahlin please have a look the failure: https://github.com/sundb/redis/actions/runs/10207316287/job/28241980209

Got it and I will check it.

tests/integration/redis-cli.tcl

…3411) When the server restarts while the CLI is connecting, the reconnection does not automatically select the previous db. This may lead users to believe they are still in the previous db, in fact, they are in db0. This PR will automatically reset the current dbnum and `cliSelect()` again when reconnecting. --------- Co-authored-by: debing.sun <[email protected]>

### New Features in binary distributions - 7 new data structures: JSON, Time series, Bloom filter, Cuckoo filter, Count-min sketch, Top-k, t-digest - Redis scalable query engine (including vector search) ### Potentially breaking changes - #12272 `GETRANGE` returns an empty bulk when the negative end index is out of range - #12395 Optimize `SCAN` command when matching data type ### Bug fixes - #13510 Fix `RM_RdbLoad` to enable AOF after RDB loading is completed - #13489 `ACL CAT` - return module commands - #13476 Fix a race condition in the `cache_memory` of `functionsLibCtx` - #13473 Fix incorrect lag due to trimming stream via `XTRIM` command - #13338 Fix incorrect lag field in `XINFO` when tombstone is after the `last_id` of the consume group - #13470 On `HDEL` of last field - update the global hash field expiration data structure - #13465 Cluster: Pass extensions to node if extension processing is handled by it - #13443 Cluster: Ensure validity of myself when loading cluster config - #13422 Cluster: Fix `CLUSTER SHARDS` command returns empty array ### Modules API - #13509 New API calls: `RM_DefragAllocRaw`, `RM_DefragFreeRaw`, and `RM_RegisterDefragCallbacks` - defrag API to allocate and free raw memory ### Performance and resource utilization improvements - #13503 Avoid overhead of comparison function pointer calls in listpack `lpFind` - #13505 Optimize `STRING` datatype write commands - #13499 Optimize `SMEMBERS` command - #13494 Optimize `GEO*` commands reply - #13490 Optimize `HELLO` command - #13488 Optimize client query buffer - #12395 Optimize `SCAN` command when matching data type - #13529 Optimize `LREM`, `LPOS`, `LINSERT`, and `LINDEX` commands - #13516 Optimize `LRANGE` and other commands that perform several writes to client buffers per call - #13431 Avoid `used_memory` contention when updating from multiple threads ### Other general improvements - #13495 Reply `-LOADING` on replica while flushing the db ### CLI tools - #13411 redis-cli: Fix wrong `dbnum` showed after the client reconnected ### Notes - No backward compatibility for replication or persistence. - Additional distributions, upgrade paths, features, and improvements will be introduced in upcoming pre-releases. - With the GA release of 8.0 we will deprecate Redis Stack.

vitahlin added 4 commits July 12, 2024 01:52

Test add test for redis-cli db_num

41e733d

Fix wrong db_num in redis-cli after reconnected

8c9e180

Test add external:skip for test

b597098

Merge branch 'unstable' into fix-dbnum-error-after-cli-reconnect

93f0ea6

sundb reviewed Jul 13, 2024

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src/redis-cli.c Show resolved Hide resolved

Doc add comment for redis-cli reconnect

1462788

sundb reviewed Jul 18, 2024

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src/redis-cli.c Outdated Show resolved Hide resolved

Update src/redis-cli.c

06b5784

Co-authored-by: debing.sun <[email protected]>

sundb reviewed Jul 18, 2024

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