Database Administrators Stack Exchange
Database Administrators Stack Exchange

Questions tagged [rails]

Rails is a cross-platform model-view-controller-centric application framework for Ruby. Use this tag for database-related Rails questions.

46 questions
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MySQL create index with LOCK=NONE still locks a table

I have the following MySQL RoR Migrations: class ReindexRpushNotification < ActiveRecord::Migration def up execute("DROP INDEX `index_rpush_notifications_multi` ON rpush_notifications;") execute("ALTER TABLE rpush_notifications ADD INDEX…
Rubycon
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1 answer

PostgreSQL 9.3 Amazon RDS gives error while using UUID-OSSP extension for generating uuid

I have created DB instance on RDS and used below function. It gave error while with the same PostgreSQL version on a local development machine it works fine. create or replace function uuid() returns uuid as 'uuid-ossp', 'uuid_generate_v1' volatile…
Rameshwar RV
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5
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1 answer

How to convert time without time zone to timestamp without time zone in PostgreSQL?

I received this error when trying to alter a column of type time to type timestamp: PG::CannotCoerce: ERROR: cannot cast type time without time zone to timestamp without time zone It's not important to me how the existing times are converted, but…
at.
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4
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What can I do to monitor "out of shared memory" issues?

I'm new to database administration and I would really like some advice on what tools I could use or what I could do to monitor "out of shared memory" issues. I've been seeing these "out of shared memory" messages when I've been running rspec which…
alexia
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4
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2 answers

MySQL: How to decrease sleep process's time out?

When I run 'show processlist;', then I get so many sleep processes. I set wait_timeout and interactive_timeout to 60 in my.cnf. But, sleep process is not died when time 60 on processlist. I found that sleep process is died when time is 7900. What…
WitchOfCloud
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4
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1 answer

Inventory management in Rails

I'm creating a inventory management app in rails. I have an User Table and a Recipe table, there is also some tables with types of material (pens, sharpies, paper, and so on). Because there is a lot of types of paper, pens and other things, and…
Victor Hugo Macias Quiroz
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2 answers

Efficient schema to handle time interval queries on a huge table?

We have huge table (+10 millions rows) where we aggregate the values by a using a time interval search on a Datetime column. And right now, to build single page on our app, we are querying this table several times, resulting in a high delay on our…
Peoplee
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1 answer

Copying database to different hard disk

Total noob at database administration here, excuse my ignorance. I have a server running a Rails application that's using PostgreSQL. The database is saved on drive /z/, which seems to have filled up. I want to put a higher capacity drive and shift…
Achint
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2 answers

Set search path for Postgres in a Rails app

I have a project in heroku. I have the URI that enables me to connect with the database in my external rails app. How do I change or set the search path in ruby code?
Dan Dunclace
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How to store short stories for access to individual sentences?

I am designing a database for the first time ever (using PostgreSQL), and am wondering about the most efficient/logical way of storing a body of text (aka, a story). The conflict stems from the fact that the user will access text bodies in two…
michaelsking1993
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1 answer

In Rails: How is existing data affected by data type change?

I'm working on a Rails app and would like to change the datatype for an existing column. It's currently a DateTime type, and I want to change it to a Date type. I found a way to do this here, but in this case, the person was not worried about…
tinezekis
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1 answer

PostgreSQL: restore a record from a backup

We have a Rails app backed by a PostgreSQL DB and hosted on Heroku. We recently had a bug that deleted some (very few before we caught it) records. Excuse my ignorance but is there a straightforward way to directly pull a record (or 3) off of a…
Meltemi
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On Heroku in production, how can I copy database A to database B on command?

From my local terminal, I can use the following commands to do what I need to do: heroku pgbackups:capture --expire heroku pgbackups:restore charcoal --confirm max-kiosk However, I want to do this from the controller of my rails app, when the…
user2168130
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1 answer

Can’t connect to local PostgresSQL server

I have the Postres app installed an running on my Mac. And it has worked beautifully. I don’t know what changed, but now I cannot connect to it from Rails, PG Commander, PG Admin or the command psql -h localhost. However, I can connect with just…
David Beck
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1 answer

Why add indexes to these columns in the Database?

I am trying to get my head around this code. It's from the Rails Tutorial Book and is part of the process of making a twitter like application. class CreateRelationships < ActiveRecord::Migration def change create_table :relationships do…
John
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