Create partial index for postgresql jsonb field - ruby-on-rails

Question

I am trying to add a partial index to postgresql jsonb column. The jsonb column is named: email_provider. I have tried adding a partial index on the column as shown below but it throws different error like this PG::UndefinedColumn: ERROR: column "email_povider" does not exist and at other times it raises the error: PG::AmbiguousFunction: ERROR: operator is not unique: unknown -> unknown
The partial index in the rails-5 migration looks like this:
add_index :accounts, :name, name: "index_accounts_on_email_provider_kind", using: :gin, where: "('email_provider' -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com') AND ('email_povider' -> 'amazon ses' ->> 'smtp_host' = 'www.awses.com')"
The json for the email_provider column looks like this:
{
"email_provider": {
"sparkpost": {
"smtp_host": "www.sparkpost.com",
"smtp_port": ""
},
"aws ses": {
"smtp_host": "www.amazon/ses.com ",
"smtp_port": " ",
"username": " ",
"password": " "
}
}
}
The table looks like this:
class CreateAccounts < ActiveRecord::Migration[5.0]
def change
create_table :accounts do |t|
t.string :name, null: false
t.jsonb :email_provider, null: false
t.jsonb :social_account, default: '[]', null: false
t.timestamps
end
add_index :accounts, :name, name: "index_accounts_on_email_provider_kind", using: :gin, where: "('email_provider' -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com') AND ('email_povider' -> 'amazon ses' ->> 'smtp_host' = 'www.awses.com')"
add_index :accounts, :name, name: "index_accounts_on_social_account_type", using: :gin, where: " 'social_account' #> [{'type': 'facebook'}] AND 'social_account' #> [{'type': 'twitter'}]"
end
end
Update
Based on slight adjustment to the accepted answer below, the code I am using to create btree not gin index in rails activerecord is shown below. It creates a btree index because we are using the name column which is of string datatype and not jsonb as described here :
add_index :accounts, :name, name: "index_accounts_on_name_email_provider", where: "email_provider -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com' AND email_provider -> 'amazon ses' ->> 'smtp_host' = 'www.awses.com' "
add_index :accounts, :name, name: "index_accounts_on_name_social_account", where: " social_account #> '[{\"type\": \"facebook\"}]'::jsonb AND social_account #> '[{\"type\": \"twitter\"}]'::jsonb"

Answer 1

I think you need something like that:
add_index :accounts, :email_provider, name: "index_accounts_on_email_provider_kind", using: :gin, where: "(email_provider -> 'email_provider' -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com') AND (email_provider -> 'email_povider' -> 'amazon ses' ->> 'smtp_host' = 'www.awses.com')"
I've changed the second argument of add_index to :email_provider because that's the column name. Also, for the the where clause, I changed
'email_provider' -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com'
to
email_provider -> 'email_provider' -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com'
because the -> operator expects it left argument to be a json(b) value, but you provided a string. So e.g. email_provider -> 'email_provider' extracts the value corresponding to email_provider from the column called email_provider. Note that this last line can be written more compactly as:
email_provider #>> '{email_provider,sparkpost,smtp_host}' = 'www.sparkpost.com'
by using the #>> which extracts a "path" from a josn(b) object. So the add_index statement can be written as:
add_index :accounts, :email_provider, name: "index_accounts_on_email_provider_kind", using: :gin, where: "(email_provider #>> '{email_provider,sparkpost,smtp_host}' = 'www.sparkpost.com') AND (email_provider -> '{email_povider,amazon ses,smtp_host}' = 'www.awses.com')"
For you second index, you should try something like:
where: " social_account -> 'social_account' #> '[{\"type\": \"facebook\"}]'::jsonb AND social_account -> 'social_account' #> '[{\"type\": \"twitter\"}]'::jsonb"
In this case, I did the same think with the column as in the first case. I also changed the right argument of #>, which has to be a jsonb value. So you must define it as a JSON string, which requires double quotes for strings (also notice that we have to escape them for ruby), and then I type cast that string to jsonb to get the desired type.