Ben Chuanlong Du's Blog

It is never too late to learn.

Tips on Darglint

Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

Tips and Traps

  1. It is suggested that you avoid using darglint directly, but instead you can use flake8 which will automatically call darglint if it exists.

  2. Improperly escaped \n causes darglint …

Tips on sshuttle

Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

  1. sudo permission is required to run sshuttle.

  2. It's valid to run sshuttle more than once simultaneously on a single client machine, connecting to a different server every time, so you can …

Access Control in Spark SQL

Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

Grant Permission to Users

GRANT
    priv_type [, priv_type ] ...
    ON database_table_or_view_name
    TO principal_specification [, principal_specification] ...
    [WITH GRANT OPTION];

Examples:

GRANT SELECT ON table1 TO USER user1;
GRANT SELECT ON DATABASE db1 TO USER user1 …

Tips on the Linux Command ln

Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

It is suggest that you avoid using the trailing slash when you use ln to create symbolic link for a directory. This is different from the command rsync which a trailing …

Debugging Tools for Java

Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

arthas

arthas

JDK commands

Thread dump: jstack jvm_pid > (use -F if not responding)

Memory dump: jmap -dump:live,format=b,file=.hprof jvm_pid

Heap status: jmap -heap jvm_pid

GC status: jstat …

Check the CPU Limit of a Docker Container

Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

  1. Get the number in the file /sys/fs/cgroup/cpu,cpuacct/cpu.cfs_quota_us. Denote it as cfs_quota_us.

  2. Get the number in the file /sys/fs/cgroup/cpu,cpuacct/cpu.cfs_period_us. Denote …