Alter mysql tables on the fly, without locking them

If you need to perform real-time ALTER TABLE processes on MySQL (InnoDB, TokuDB) tables, a great tool for the job is the Percona Toolkit. The Percona Toolkit includes a utility (pt-online-schema-change) to perform such a process, without write-locking tables, or having to manually create a temporary table and triggers to synchronize the data during the … Continue reading Alter mysql tables on the fly, without locking them

MariaDB 10.0: How to migrate from InnoDB to TokuDB

This is only to remember what I did to migrate from InnoDB to TokuDB on a MariaDB cluster. TokuDB settings are specific to my environment, so please don’t ask me what/how/why. root@dbrfoo:~# mysql -u root -p MariaDB [(none)]> INSTALL SONAME ‘ha_tokudb’; Query OK, 0 rows affected (0.07 sec) MariaDB [(none)]> show engines; +——————–+———+—————————————————————————-+————–+——+————+ | Engine … Continue reading MariaDB 10.0: How to migrate from InnoDB to TokuDB

VMware modules, Arch Linux & kernel 4.8.13

After upgrading the kernel to 4.8.13-1-ARCH some of the vmware kernel modules failed to compile: /tmp/modconfig-6BT70S/vmmon-only/linux/hostif.c:1592:47: error: ‘NR_ANON_PAGES’ undeclared (first use in this function) /tmp/modconfig-BBuLH6/vmnet-only/netif.c:468:7: error: ‘struct net_device’ has no member named ‘trans_start’; did you mean ‘mem_start’? The fix:

Custom Elasticsearch template with custom field mapping

Disclaimer: I am writing this post mostly for me to remember how and what I did to solve wrong field mapping in elasticsearch. Quote from Elasticsearch Dynamic Mapping documentation page When Elasticsearch encounters a previously unknown field in a document, it uses dynamic mapping to determine the datatype for the field and automatically adds the … Continue reading Custom Elasticsearch template with custom field mapping

Full Disk Encryption on Arch Linux: NVMe, GRUB2, LVM and LUKS

Last week I had to install my new work computer. Although I am a Debian guy, I thought I should give a chance to Arch Linux as well. In theory full disk encryption and Linux is not a big deal (there’s a lot of documentation out there) and it should be pretty straight forward. In practice, … Continue reading Full Disk Encryption on Arch Linux: NVMe, GRUB2, LVM and LUKS

Mutt: delete duplicate e-mail messages

Disclaimer: at some point I found this page describing how to delete duplicate e-mail messages with mutt. Unfortunately the page is not up anymore (HTTP 404) and I took the liberty to post it on my blog. Anyway, credit goes to Marianne Promberger. The original page was here: http://promberger.info/linux/2008/03/31/mutt-delete-duplicate-e-mail-messages/ Here we go: Sometimes, if you consolidate different … Continue reading Mutt: delete duplicate e-mail messages

Be notified when critical battery level is reached

Ever happened to be focused on something and miss the fact that your laptop is running out of battery? And to lose your work? Yesterday happened twice! “Really? Hmm… I need to fix this as soon as possible.” I googled a bit and this stackexchange post  popped up. Nice, great! But being notified even when you’re … Continue reading Be notified when critical battery level is reached

I can't memorize much, so I take notes!