92b2c74ce1
When I proposed using serializable transactions I was hoping we would be able to refresh data of individual users concurrently. Unfortunately upon closer inspection it was revealed this was not the case. This could result in a lot of queries failing due to serialization errors, overloading the database in the process (given enough workers trying to update the target table). To work around this we're now using a Redis lease that is cancelled upon completion. This ensures we can update the data of different users concurrently without overloading the database. The code will try to obtain the lease until it succeeds, waiting at least 1 second between retries. This is necessary as we may otherwise end up _not_ updating the data which is not an option.
76 lines
1.6 KiB
Ruby
76 lines
1.6 KiB
Ruby
module Gitlab
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module Database
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# The max value of INTEGER type is the same between MySQL and PostgreSQL:
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# https://www.postgresql.org/docs/9.2/static/datatype-numeric.html
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# http://dev.mysql.com/doc/refman/5.7/en/integer-types.html
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MAX_INT_VALUE = 2147483647
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def self.adapter_name
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connection.adapter_name
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end
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def self.mysql?
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adapter_name.casecmp('mysql2').zero?
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end
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def self.postgresql?
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adapter_name.casecmp('postgresql').zero?
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end
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def self.version
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database_version.match(/\A(?:PostgreSQL |)([^\s]+).*\z/)[1]
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end
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def self.nulls_last_order(field, direction = 'ASC')
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order = "#{field} #{direction}"
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if Gitlab::Database.postgresql?
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order << ' NULLS LAST'
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else
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# `field IS NULL` will be `0` for non-NULL columns and `1` for NULL
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# columns. In the (default) ascending order, `0` comes first.
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order.prepend("#{field} IS NULL, ") if direction == 'ASC'
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end
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order
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end
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def self.random
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Gitlab::Database.postgresql? ? "RANDOM()" : "RAND()"
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end
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def true_value
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if Gitlab::Database.postgresql?
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"'t'"
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else
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1
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end
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end
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def false_value
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if Gitlab::Database.postgresql?
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"'f'"
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else
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0
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end
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end
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def self.connection
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ActiveRecord::Base.connection
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end
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private_class_method :connection
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def self.database_version
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row = connection.execute("SELECT VERSION()").first
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if postgresql?
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row['version']
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else
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row.first
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end
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end
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private_class_method :database_version
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end
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end
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