bin/kafka-topics.sh --zookeeper localhost:2181 --list
bin/kafka-topics.sh --zookeeper localhost:2181 --describe --topic mytopic
bin/kafka-topics.sh --zookeeper localhost:2181 --alter --topic mytopic --config retention.ms=1000
... wait a minute ...
Farid Uyar fuyar
ursuad
/ kafka-cheat-sheet.md
Last active
March 21, 2026 02:57
Quick command reference for Apache Kafka
bin/kafka-topics.sh --zookeeper localhost:2181 --list
bin/kafka-topics.sh --zookeeper localhost:2181 --alter --topic mytopic --config retention.ms=1000
... wait a minute ...
bin/kafka-topics.sh --zookeeper localhost:2181 --alter --topic mytopic --delete-config retention.ms
bastman
/ docker-cleanup-resources.md
Created
March 31, 2016 05:55
docker cleanup guide: containers, images, volumes, networks
Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...
// see: https://github.com/chadoe/docker-cleanup-volumes
$ docker volume rm $(docker volume ls -qf dangling=true)
$ docker volume ls -qf dangling=true | xargs -r docker volume rm
pkirkovsky
/ yubikey-reset.sh
Last active
February 28, 2025 10:02
Utility for resetting a Yubikey to factory defaults using gpg-connect-agent. This will wipe out any stored keys and reset PINs to default values.
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| # Adapted from https://developers.yubico.com/ykneo-openpgp/ResetApplet.html | |
| gpg-connect-agent <<EOF | |
| /hex | |
| scd serialno | |
| scd apdu 00 20 00 81 08 40 40 40 40 40 40 40 40 | |
| scd apdu 00 20 00 81 08 40 40 40 40 40 40 40 40 | |
| scd apdu 00 20 00 81 08 40 40 40 40 40 40 40 40 | |
| scd apdu 00 20 00 81 08 40 40 40 40 40 40 40 40 | |
| scd apdu 00 20 00 83 08 40 40 40 40 40 40 40 40 | |
| scd apdu 00 20 00 83 08 40 40 40 40 40 40 40 40 |
miguno
/ kafka-move-leadership.sh
Last active
July 6, 2023 19:53
A simple Ops helper script for Apache Kafka to generate a partition reassignment JSON snippet for moving partition leadership away from a given Kafka broker. Use cases include 1) safely restarting a broker while minimizing risk of data loss, 2) replacing a broker, 3) preparing a broker for maintenance.
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| #!/usr/bin/env bash | |
| # | |
| # File: kafka-move-leadership.sh | |
| # | |
| # Description | |
| # =========== | |
| # | |
| # Generates a Kafka partition reassignment JSON snippet to STDOUT to move the leadership | |
| # of any replicas away from the provided "source" broker to different, randomly selected | |
| # "target" brokers. Run this script with `-h` to show detailed usage instructions. |
Kartones
/ postgres-cheatsheet.md
Last active
March 19, 2026 09:33
PostgreSQL command line cheatsheet
Magic words:
psql -U postgresSome interesting flags (to see all, use -h or --help depending on your psql version):
-E: will describe the underlaying queries of the\commands (cool for learning!)-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)
rgreenjr
/ postgres_queries_and_commands.sql
Last active
March 14, 2026 17:03
Useful PostgreSQL Queries and Commands
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| -- show running queries (pre 9.2) | |
| SELECT procpid, age(clock_timestamp(), query_start), usename, current_query | |
| FROM pg_stat_activity | |
| WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' | |
| ORDER BY query_start desc; | |
| -- show running queries (9.2) | |
| SELECT pid, age(clock_timestamp(), query_start), usename, query | |
| FROM pg_stat_activity | |
| WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' |
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| Latency Comparison Numbers (~2012) | |
| ---------------------------------- | |
| L1 cache reference 0.5 ns | |
| Branch mispredict 5 ns | |
| L2 cache reference 7 ns 14x L1 cache | |
| Mutex lock/unlock 25 ns | |
| Main memory reference 100 ns 20x L2 cache, 200x L1 cache | |
| Compress 1K bytes with Zippy 3,000 ns 3 us | |
| Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
| Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |