## A Multithreaded, Transaction-Based Locking Strategy for Containers Bob Steagall CppCon 2020 KEWB COMPUTING ## Overview • Sharing a container among multiple threads • A motivating problem • Some than ever ## Sharing a Container – Avoiding Race Conditions • If all threads are readers... • No locking is required • If the number of reads is much larger than the number of writes... • We might be writes? • A per-element mutex strategy might work... • ... if a given write operation requires locking exactly one element ## Sharing a Container – Avoiding Race Conditions • What about the case where

from repodata.jlap; implies 'lock'. lock: use locking when reading, updating index (repodata.json) cache. Now enabled. --no-lock Disable locking when reading, updating index (repodata.json) cache from repodata.jlap; implies 'lock'. lock: use locking when reading, updating index (repodata.json) cache. Now enabled. --no-lock Disable locking when reading, updating index (repodata.json) cache from repodata.jlap; implies 'lock'. lock: use locking when reading, updating index (repodata.json) cache. Now enabled. --no-lock Disable locking when reading, updating index (repodata.json) cache

Copied Value ■ Thread-Specific Storage ■ Future ## Dealing with Mutation ■ Scoped Locking ■ Strategized Locking ■ Thread-Safe Interface ■ Guarded Suspension Active Object Monitor Object Reactor Thread-Specific Storage ■ Future Active Object ## Dealing with Mutation ■ Scoped Locking ■ Strategized Locking ■ Thread-Safe Interface Monitor Object ■ Guarded Suspension Reactor ## Copied Value Mutation ■ Scoped Locking ■ Strategized Locking Monitor Object ■ Thread-Safe Interface ■ Guarded Suspension Reactor ## Scoped Locking ## Scoped Locking is RAI applied to locking ## I dea: - Bind

generating mo files in repository. • Translation process • Suggestion voting • Translation locking • Checks and fixups • Custom automatic fixups • Customizing checks • Fine contain example.com as domain? ## Enable indexing offloading Enable OFFLOAD INDEXING to prevent locking issues and improve performance. Don’t forget to schedule indexing in background job to keep the index translation for translating [Users, Managers] Can lock translation while translating (see Translation locking). Can add suggestion [Users, Managers, Guests] Can add new suggestions. Can use machine translation

contain example.com as domain? ## Enable indexing offloading Enable OFFLOAD_INDEXING to prevent locking issues and improve performance. Don’t forget to schedule indexing in background job to keep the index for translating [Users, Managers, Owners] Can lock translation while translating (see Translation locking). Can add suggestion [Users, Managers, Owners, Guests] Can add new suggestions. Can use machine OFFLOAD INDEXING. The first approach (immediate updates) allows more up to date index, but suffers locking issues in some setup (e.g., Apache's mod_wski) and produces more fragmented index. Offloaded

already translated strings or not. |Recent changes|Search|Files|Automatic translation|Git maintenance|Locking|Share|Activity| |---|---|---|---|---|---|---|---| ## Download You can download file for offline contain example.com as domain? ## Enable indexing offloading Enable OFFLOAD_INDEXING to prevent locking issues and improve performance. Don’t forget to schedule indexing in background job to keep the index translation for translating [Users, Managers] Can lock translation while translating (see Translation locking). Can add suggestion [Users, Managers, Guests] Can add new suggestions. Can use machine translation

use PostgreSQL - MySQL or MariaDB - Unicode issues in MySQL - Transaction locking - Creating database in MySQL - Configuring Weblate to use MySQL - Other configurations generating mo files in repository • Translation process • Suggestion voting • Translation locking • Additional information on source strings • Strings_prioritization • Quality_check utf8mb4 by: ALTER DATABASE weblate CHARACTER SET utf8mb4; ## Transaction locking MySQL by default uses has different transaction locking scheme than other databases and in case you see errors like Deadlock

use PostgreSQL - MySQL or MariaDB - Unicode issues in MySQL - Transaction locking - Creating database in MySQL - Configuring Weblate to use MySQL - Other configurations generating mo files in repository • Translation process • Suggestion voting • Translation locking • Additional information on source strings • Strings_prioritization • Quality utf8mb4 by: ALTER DATABASE weblate CHARACTER SET utf8mb4; ## Transaction locking MySQL by default uses has different transaction locking scheme than other databases and in case you see errors like Deadlock

use PostgreSQL - MySQL or MariaDB - Unicode issues in MySQL - Transaction locking - Creating database in MySQL - Configuring Weblate to use MySQL - Other configurations generating mo files in repository • Translation process • Suggestion voting • Translation locking • Additional information on source strings • Strings prioritization • Quality utf8mb4 by: ALTER DATABASE weblate CHARACTER SET utf8mb4; ## Transaction locking MySQL by default uses has different transaction locking scheme than other databases and in case you see errors like Deadlock

use PostgreSQL - MySQL or MariaDB - Unicode issues in MySQL - Transaction locking - Creating database in MySQL - Configuring Weblate to use MySQL - Other configurations files in repository. - Translation process - Suggestion voting - Translation locking - Additional information on source strings - Strings prioritization - Quality com/blog/2014/07/29/using-innodb-large-prefix-to-avoid-error-1071/] ## Transaction locking MySQL by default uses has different transaction locking scheme than other databases and in case you see errors like Deadlock