Class: PgSync::TableSync

Inherits:
Object
  • Object
show all
Includes:
Utils
Defined in:
lib/pgsync/table_sync.rb

Constant Summary

Constants included from Utils

Utils::COLOR_CODES

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Utils

#colorize, #confirm_tables_exist, #db_config_file, #deprecated, #escape, #first_schema, #friendly_name, #log, #monotonic_time, #output, #quote_ident, #quote_ident_full, #quote_string, #task_name, #warning

Constructor Details

#initialize(source:, destination:, tasks:, opts:, resolver:) ⇒ TableSync

Returns a new instance of TableSync.



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# File 'lib/pgsync/table_sync.rb', line 7

def initialize(source:, destination:, tasks:, opts:, resolver:)
  @source = source
  @destination = destination
  @tasks = tasks
  @opts = opts
  @resolver = resolver
end

Instance Attribute Details

#destination ⇒ Object (readonly)

Returns the value of attribute destination.



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# File 'lib/pgsync/table_sync.rb', line 5

def destination
  @destination
end

#opts ⇒ Object (readonly)

Returns the value of attribute opts.



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# File 'lib/pgsync/table_sync.rb', line 5

def opts
  @opts
end

#resolver ⇒ Object (readonly)

Returns the value of attribute resolver.



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# File 'lib/pgsync/table_sync.rb', line 5

def resolver
  @resolver
end

#source ⇒ Object (readonly)

Returns the value of attribute source.



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# File 'lib/pgsync/table_sync.rb', line 5

def source
  @source
end

#tasks ⇒ Object (readonly)

Returns the value of attribute tasks.



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# File 'lib/pgsync/table_sync.rb', line 5

def tasks
  @tasks
end

Instance Method Details

#add_columns ⇒ Object 



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# File 'lib/pgsync/table_sync.rb', line 31

def add_columns
  source_columns = columns(source)
  destination_columns = columns(destination)

  tasks.each do |task|
    task.from_columns = source_columns[task.table] || []
    task.to_columns = destination_columns[task.table] || []
  end
end

#add_primary_keys ⇒ Object 



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# File 'lib/pgsync/table_sync.rb', line 41

def add_primary_keys
  destination_primary_keys = primary_keys(destination)

  tasks.each do |task|
    task.to_primary_key = destination_primary_keys[task.table] || []
  end
end

#add_sequences ⇒ Object 



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# File 'lib/pgsync/table_sync.rb', line 49

def add_sequences
  source_sequences = sequences(source)
  destination_sequences = sequences(destination)

  tasks.each do |task|
    shared_columns = Set.new(task.shared_fields)

    task.from_sequences = (source_sequences[task.table] || []).select { |s| shared_columns.include?(s.column) }
    task.to_sequences = (destination_sequences[task.table] || []).select { |s| shared_columns.include?(s.column) }
  end
end

#columns(data_source) ⇒ Object 



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# File 'lib/pgsync/table_sync.rb', line 135

def columns(data_source)
  query = <<~SQL
    SELECT
      table_schema AS schema,
      table_name AS table,
      column_name AS column,
      data_type AS type
    FROM
      information_schema.columns
    WHERE
      is_generated = 'NEVER'
    ORDER BY 1, 2, 3
  SQL
  data_source.execute(query).group_by { |r| Table.new(r["schema"], r["table"]) }.map do |k, v|
    [k, v.map { |r| {name: r["column"], type: r["type"]} }]
  end.to_h
end

#display_item(item) ⇒ Object 



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# File 'lib/pgsync/table_sync.rb', line 313

def display_item(item)
  messages = []
  messages << task_name(item)
  messages << item.opts[:sql] if item.opts[:sql]
  messages.join(" ")
end

#fail_sync(failed_tables) ⇒ Object

Raises:



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# File 'lib/pgsync/table_sync.rb', line 309

def fail_sync(failed_tables)
  raise Error, "Sync failed for #{failed_tables.size} table#{failed_tables.size == 1 ? nil : "s"}: #{failed_tables.join(", ")}"
end

#maybe_defer_constraints ⇒ Object

TODO add option to open transaction on source when manually specifying order of tables



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# File 'lib/pgsync/table_sync.rb', line 264

def maybe_defer_constraints
  if opts[:disable_integrity] || opts[:disable_integrity_v2]
    # create a transaction on the source
    # to ensure we get a consistent snapshot
    source.transaction do
      yield
    end
  elsif opts[:defer_constraints_v1] || opts[:defer_constraints_v2]
    destination.transaction do
      if opts[:defer_constraints_v2]
        table_constraints = non_deferrable_constraints(destination)
        table_constraints.each do |table, constraints|
          constraints.each do |constraint|
            destination.execute("ALTER TABLE #{quote_ident_full(table)} ALTER CONSTRAINT #{quote_ident(constraint)} DEFERRABLE")
          end
        end
      end

      destination.execute("SET CONSTRAINTS ALL DEFERRED")

      # create a transaction on the source
      # to ensure we get a consistent snapshot
      source.transaction do
        yield
      end

      # set them back
      # there are 3 modes: DEFERRABLE INITIALLY DEFERRED, DEFERRABLE INITIALLY IMMEDIATE, and NOT DEFERRABLE
      # we only update NOT DEFERRABLE
      # https://www.postgresql.org/docs/current/sql-set-constraints.html
      if opts[:defer_constraints_v2]
        destination.execute("SET CONSTRAINTS ALL IMMEDIATE")

        table_constraints.each do |table, constraints|
          constraints.each do |constraint|
            destination.execute("ALTER TABLE #{quote_ident_full(table)} ALTER CONSTRAINT #{quote_ident(constraint)} NOT DEFERRABLE")
          end
        end
      end
    end
  else
    yield
  end
end

#non_deferrable_constraints(data_source) ⇒ Object 



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# File 'lib/pgsync/table_sync.rb', line 153

def non_deferrable_constraints(data_source)
  query = <<~SQL
    SELECT
      table_schema AS schema,
      table_name AS table,
      constraint_name
    FROM
      information_schema.table_constraints
    WHERE
      constraint_type = 'FOREIGN KEY' AND
      is_deferrable = 'NO'
  SQL
  data_source.execute(query).group_by { |r| Table.new(r["schema"], r["table"]) }.map do |k, v|
    [k, v.map { |r| r["constraint_name"] }]
  end.to_h
end

#perform ⇒ Object 



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# File 'lib/pgsync/table_sync.rb', line 15

def perform
  confirm_tables_exist(destination, tasks, "destination")

  add_columns

  add_primary_keys

  add_sequences unless opts[:no_sequences]

  show_notes

  # don't sync tables with no shared fields
  # we show a warning message above
  run_tasks(tasks.reject { |task| task.shared_fields.empty? })
end

#primary_keys(data_source) ⇒ Object 



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# File 'lib/pgsync/table_sync.rb', line 89

def primary_keys(data_source)
  # https://stackoverflow.com/a/20537829
  # TODO can simplify with array_position in Postgres 9.5+
  query = <<~SQL
    SELECT
      nspname AS schema,
      relname AS table,
      pg_attribute.attname AS column,
      format_type(pg_attribute.atttypid, pg_attribute.atttypmod),
      pg_attribute.attnum,
      pg_index.indkey
    FROM
      pg_index, pg_class, pg_attribute, pg_namespace
    WHERE
      indrelid = pg_class.oid AND
      pg_class.relnamespace = pg_namespace.oid AND
      pg_attribute.attrelid = pg_class.oid AND
      pg_attribute.attnum = any(pg_index.indkey) AND
      indisprimary
  SQL
  data_source.execute(query).group_by { |r| Table.new(r["schema"], r["table"]) }.map do |k, v|
    [k, v.sort_by { |r| r["indkey"].split(" ").index(r["attnum"]) }.map { |r| r["column"] }]
  end.to_h
end

#run_tasks(tasks, &block) ⇒ Object 



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# File 'lib/pgsync/table_sync.rb', line 170

def run_tasks(tasks, &block)
  notices = []
  failed_tables = []
  started_at = {}

  show_spinners = output.tty? && !opts[:in_batches] && !opts[:debug]
  if show_spinners
    spinners = TTY::Spinner::Multi.new(format: :dots, output: output)
    task_spinners = {}
  end

  start = lambda do |task, i|
    message = ":spinner #{display_item(task)}"

    if show_spinners
       = spinners.register(message)
      .auto_spin
      task_spinners[task] = 
    elsif opts[:in_batches]
      log message.sub(":spinner", "⠋")
    end

    started_at[task] = monotonic_time
  end

  finish = lambda do |task, i, result|
    time = (monotonic_time - started_at[task]).round(1)

    success = result[:status] == "success"

    message =
      if result[:message]
        "(#{result[:message].lines.first.to_s.strip})"
      else
        "- #{time}s"
      end

    notices.concat(result[:notices])

    if show_spinners
       = task_spinners[task]
      if success
        .success(message)
      else
        .error(message)
      end
    else
      status = success ? "✔" : "✖"
      log [status, display_item(task), message].join(" ")
    end

    unless success
      failed_tables << task_name(task)
      fail_sync(failed_tables) if opts[:fail_fast]
    end
  end

  options = {start: start, finish: finish}

  jobs = opts[:jobs]

  # disable multiple jobs for defer constraints and disable integrity
  # so we can use a transaction to ensure a consistent snapshot
  if opts[:debug] || opts[:in_batches] || opts[:defer_constraints_v1] || opts[:defer_constraints_v2] || opts[:disable_integrity] || opts[:disable_integrity_v2]
    warning "--jobs ignored" if jobs
    jobs = 0
  end

  if windows?
    options[:in_threads] = jobs || 4
  else
    options[:in_processes] = jobs if jobs
  end

  maybe_defer_constraints do
    # could try to use `raise Parallel::Kill` to fail faster with --fail-fast
    # see `fast_faster` branch
    # however, need to make sure connections are cleaned up properly
    Parallel.each(tasks, **options) do |task|
      source.reconnect_if_needed
      destination.reconnect_if_needed

      task.perform
    end
  end

  notices.each do |notice|
    warning notice
  end

  fail_sync(failed_tables) if failed_tables.any?
end

#sequences(data_source) ⇒ Object 



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# File 'lib/pgsync/table_sync.rb', line 61

def sequences(data_source)
  query = <<~SQL
    SELECT
      nt.nspname as schema,
      t.relname as table,
      a.attname as column,
      n.nspname as sequence_schema,
      s.relname as sequence
    FROM
      pg_class s
    INNER JOIN
      pg_depend d ON d.objid = s.oid
    INNER JOIN
      pg_class t ON d.objid = s.oid AND d.refobjid = t.oid
    INNER JOIN
      pg_attribute a ON (d.refobjid, d.refobjsubid) = (a.attrelid, a.attnum)
    INNER JOIN
      pg_namespace n ON n.oid = s.relnamespace
    INNER JOIN
      pg_namespace nt ON nt.oid = t.relnamespace
    WHERE
      s.relkind = 'S'
  SQL
  data_source.execute(query).group_by { |r| Table.new(r["schema"], r["table"]) }.map do |k, v|
    [k, v.map { |r| Sequence.new(r["sequence_schema"], r["sequence"], column: r["column"]) }]
  end.to_h
end

#show_notes ⇒ Object 



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# File 'lib/pgsync/table_sync.rb', line 114

def show_notes
  # for tables
  resolver.notes.each do |note|
    warning note
  end

  # for columns and sequences
  tasks.each do |task|
    task.notes.each do |note|
      warning "#{task_name(task)}: #{note}"
    end
  end

  # for non-deferrable constraints
  if opts[:defer_constraints_v1]
    constraints = non_deferrable_constraints(destination)
    constraints = tasks.flat_map { |t| constraints[t.table] || [] }
    warning "Non-deferrable constraints: #{constraints.join(", ")}" if constraints.any?
  end
end

#windows? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pgsync/table_sync.rb', line 320

def windows?
  Gem.win_platform?
end