redis – Page 6 – Türker Yıldırım

Client-side caching, and the invalidation Redis pushes

NoteApril 28, 20201 min read

A local in-process cache in front of Redis removes the round trip and has no way to know when the value changed — which is why almost nobody…

TLS for Redis, and the latency it costs

NoteApril 28, 20202 min read

Redis had no TLS, so the usual arrangements were a private network, an SSH tunnel or stunnel. 6.0 builds it in, and the honest question is whether it…

Command categories beat command lists in an ACL

NoteApril 24, 20202 min read

Enumerating permitted commands produces a list that is wrong the moment Redis adds one, and the additions are exactly the commands nobody has considered. -@dangerous is the single…

A stampede lock, and what the losers should do

NoteApril 21, 20202 min read

An expensive cached value expires under load and every concurrent request misses simultaneously, so forty workers run the same four-second query at once. What the losers do is…

Create a Redis ACL user for one service

SnippetApril 14, 20201 min read

RESP3, and the client library that has to agree

NoteApril 11, 20201 min read

6.0 introduced a new protocol with typed replies, and the client opts in with HELLO 3 — so the server supporting it changes nothing until the library does.…

Redis 6 and the shared password that was everywhere

Deep diveApril 9, 202010 min read

One password, six services, and FLUSHALL available to all of them. 6.0 landed in April with users — and the keyspace pattern is where the isolation actually is.

Redis 6 ACLs, and the user per service

NoteApril 7, 20202 min read

Redis had one password and no users, so every service that could read the cache could also flush it — and the credential was the same string in…

XPENDING with IDLE is how you find a dead consumer’s work

NoteOctober 22, 20192 min read

An entry delivered to a consumer and never acknowledged stays in the pending entries list indefinitely, which is the mechanism that makes recovery possible and the one that…

Consumer groups distribute; a plain read does not

NoteSeptember 8, 20191 min read

Reading a Redis stream directly gives every consumer every entry, which is right for fanout and wrong for a work queue. The > means entries never delivered to…