lhm | Online MySQL schema migrations | Application Framework library

by soundcloud Ruby Version: v2.2.0 License: BSD-3-Clause

X-Ray Key Features Code Snippets Community Discussions(9)Vulnerabilities Install Support

kandi X-RAY | lhm Summary

lhm is a Ruby library typically used in Server, Application Framework, Ruby On Rails applications. lhm has no bugs, it has no vulnerabilities, it has a Permissive License and it has medium support. You can download it from GitHub.

Rails style database migrations are a useful way to evolve your data schema in an agile manner. Most Rails projects start like this, and at first, making changes is fast and easy. That is until your tables grow to millions of records. At this point, the locking nature of ALTER TABLE may take your site down for an hour or more while critical tables are migrated. In order to avoid this, developers begin to design around the problem by introducing join tables or moving the data into another layer. Development gets less and less agile as tables grow and grow. To make the problem worse, adding or changing indices to optimize data access becomes just as difficult. Side effects may include black holes and universe implosion. There are few things that can be done at the server or engine level. It is possible to change default values in an ALTER TABLE without locking the table. The InnoDB Plugin provides facilities for online index creation, which is great if you are using this engine, but only solves half the problem. At SoundCloud we started having migration pains quite a while ago, and after looking around for third party solutions, we decided to create our own. We called it Large Hadron Migrator, and it is a gem for online ActiveRecord migrations.

Support

Quality

Security

License

Reuse

Support

lhm has a medium active ecosystem.

It has 1790 star(s) with 190 fork(s). There are 202 watchers for this library.

It had no major release in the last 6 months.

There are 26 open issues and 34 have been closed. On average issues are closed in 333 days. There are 10 open pull requests and 0 closed requests.

It has a neutral sentiment in the developer community.

The latest version of lhm is v2.2.0

Quality

lhm has 0 bugs and 0 code smells.

Security

lhm has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.

lhm code analysis shows 0 unresolved vulnerabilities.

There are 0 security hotspots that need review.

License

lhm is licensed under the BSD-3-Clause License. This license is Permissive.

Permissive licenses have the least restrictions, and you can use them in most projects.

Reuse

lhm releases are not available. You will need to build from source code and install.

Installation instructions, examples and code snippets are available.

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lhm Key Features

No Key Features are available at this moment for lhm.

lhm Examples and Code Snippets

No Code Snippets are available at this moment for lhm.

Community Discussions

Trending Discussions on lhm

Auto Layout - Make UITextView, not UIImageView, stretch the container view

First unique character in a string using LinkedHashMap

Ghost/copy table is many times bigger than original table

Not able to compile C source files using make. CMake error Cannot find source files but they are there

Java Linkedhashmap equals method custom implementation

Address offset in RISC-V load instructions hardcoded or not?

Sorting map by date(value) using stream Java

Prepend String Using CONCAT/CONCAT_WS with STRING_AGG results if STRING_AGG is NOT Empty or NULL?

In a linked hash map . how can I modify equals and hash code to display values?

QUESTION

Auto Layout - Make UITextView, not UIImageView, stretch the container view

Asked 2021-Sep-24 at 04:46

I have 3 views:

a UIImageView (blank, no image set)
a UITextView with isScrollEnabled set to false
a UIView container (gray background) that contains the UIImageView and UITextView

I'm trying to get the container to resize based on the UITextView's contents. It works well — but as soon as I set an image, the container seems to resize based on the UIImageView.

Shorter text Longer text After setting image

I do want the UIImageView to grow and fill the container view's height, though. I just don't want it to stretch the container view. That's the UITextView's job. Here's what my constraints look like:

And the storyboard code:

...

ANSWER

Answered 2021-Sep-24 at 04:34

You should set the vertical content compression resistance priority of the image view to be lower than the vertical content hugging priority of the text view. For example, I've set the former to "low" and the latter to "high", and it works.

Image view:

Text View:

Source https://stackoverflow.com/questions/69309447

QUESTION

First unique character in a string using LinkedHashMap

Asked 2021-Feb-27 at 16:58

Given a string, find the first non-repeating character in it and return its index. If it doesn't exist, return -1.

Examples:

...

ANSWER

Answered 2021-Feb-27 at 10:35

HashSet

The set is only used to avoid computing again a character that's already been seen. The set doesn't need to respect insertion order, as its goal is just check if an element exists. For that, HashSet is a proper option.

StringUtils has some good utils indeed, one of them is counting the occurrences of a single char/string within the source string.

As you want the first character which is unique, if the element didn't exist in the set and countMatches returns 1, you got your result.

If no uniques are found, return -1 (for example) as representation that no uniques were found in the string.

Source https://stackoverflow.com/questions/66360523

QUESTION

Ghost/copy table is many times bigger than original table

Asked 2020-Dec-02 at 06:50

Info: I am using AWS RDS Mysql 5.6.34 (500GB) instance (Without replica, just the master)

Note: Binlog is enabled & set to Row

Target: Modify a column field_1 from enum to tinyint

Extra info: I am using Rails application. So everytime I wanted to add a value to the enum, I need to write a migration. So converting the enum field to tinyint so I can add or delete a enum value without writing a migration using Active Enum

Other info: I also tried LHM but the RDS instance went out of memory at 93%

Database info before running gh-ost:

...

ANSWER

Answered 2020-Dec-02 at 06:50

I created the mysql DB from a backup of production db.

Production had innodb_file_format parameter as Barracuda

The new environment had innodb_file_format parameter as Antelope

The ROW_FORMAT for the table in production was COMPRESSED

Unfortunately Antelope db doesn't support ROW_FORMAT as COMPRESSED

If I had looked more into the details of information_schema, I could have resolved it eatlier!

Source https://stackoverflow.com/questions/64630426

QUESTION

Not able to compile C source files using make. CMake error Cannot find source files but they are there

Asked 2020-Jul-22 at 16:11

Im trying to compile the posest C++ library posest : A C/C++ Library for Robust 6DoF Pose Estimation from 3D-2D Correspondences with make. But when run the make I got the following error

...

ANSWER

Answered 2020-Jul-22 at 16:11

I had to download the tar file from the website. It is malformed and won't work.

Source https://stackoverflow.com/questions/63035981

QUESTION

Java Linkedhashmap equals method custom implementation

Asked 2020-Jun-17 at 13:50

I am trying to implement my own LinkedHashMap using chaining strategy for deal with collisions. Below code snippet shows what I have tried so far.

CustomLinkedHashMap

...

ANSWER

Answered 2020-Jun-17 at 13:50

Your equals for CustomLinkedHashMap is way too complicated. All you really need is to check the entries (and their ordering):

Source https://stackoverflow.com/questions/62420357

QUESTION

Address offset in RISC-V load instructions hardcoded or not?

Asked 2020-May-28 at 15:27

For educational purposes I used https://godbolt.org/z/7F-Lhm to translate

...

ANSWER

Answered 2020-May-28 at 15:27

and not just with lbu a0, a0(a1)?

RISC V (and MIPS) do not have a base register + base register addressing mode — they both have only one and that is base register + immediate.

So the register + register operation required for A+i has to be done with a separate add instruction.

instead of just lbu a0, 0(i)?

There is not enough room in the 32-bit instruction to hold the address of a global, so multiple instructions are used.

You have declared the variables as globals, therefore some of this code is about accessing the globals.

Source https://stackoverflow.com/questions/62060724

QUESTION

Sorting map by date(value) using stream Java

Asked 2020-May-22 at 22:45

I have Map with abbreviation as a key and time(duration) as a value

...

ANSWER

Answered 2020-May-21 at 20:15

To sort a map, try the following. Be very sure to use a LinkedHashMap because it doesn't remain sorted otherwise. You can replace Map.Entry.comparingByValue() with a Comparator of your choice.

Source https://stackoverflow.com/questions/61942671

QUESTION

Prepend String Using CONCAT/CONCAT_WS with STRING_AGG results if STRING_AGG is NOT Empty or NULL?

Asked 2020-Apr-09 at 09:58

I have JSONB data that is stored in the data column like so:

...

ANSWER

Answered 2020-Apr-09 at 09:58

Click: step-by-step demo:db<>fiddle

Source https://stackoverflow.com/questions/61072717

QUESTION

In a linked hash map . how can I modify equals and hash code to display values?

Asked 2020-Feb-13 at 01:11

public class Event extends Framework  {


    Event e;
    public LinkedHashMap Lhm;

    void addVertex(int arrival_time,int mappers_req,int mappers_location,int reducers_req,int reducers_location,int link_capacity,float demand_capacity,int deadline) {

        Lhm.put(Framework.id, new Event_para(arrival_time,mappers_req,mappers_location,reducers_req,reducers_location,link_capacity,demand_capacity,deadline));

    }
    public  Event() {
        Lhm=new LinkedHashMap();   
        System.out.println("");   
        }

...

ANSWER

Answered 2020-Feb-12 at 20:48

equals(), hashCode() and dont forget compareTo() are used by many container classes to compare objects. The LinkedHashMap uses them to sort them properly into the map. Java does automatically generate them. You only need to overwrite them if the default does not work properly.

They are not meant to produce any output!

You may override the toString() method of the object to produce output, but you also must call it somehow. E.g.

Source https://stackoverflow.com/questions/60194909

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