Module: PartitionGardener::Connection

Defined in:
lib/partition_gardener/connection.rb

Defined Under Namespace

Classes: AttachedPartition

Class Method Summary collapse

Class Method Details

.attached_partitions(table_name) ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 90

def attached_partitions(table_name)
  attached_partitions_cache[table_name] ||= fetch_attached_partitions(table_name)
end

.attached_partitions_cache ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 118

def attached_partitions_cache
  Thread.current[:partition_gardener_attached_partitions] ||= {}
end

.clear_attached_partitions_cache! ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 94

def clear_attached_partitions_cache!
  Thread.current[:partition_gardener_attached_partitions] = nil
end

.connection ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 5

def connection
  PartitionGardener.configuration.connection
end

.count_rows_in_partition(partition_name, where_condition) ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 81

def count_rows_in_partition(partition_name, where_condition)
  sql = <<~SQL
    SELECT COUNT(*) AS count
    FROM #{quoted_table(partition_name)}
    WHERE #{where_condition}
  SQL
  connection.execute(sql).first["count"].to_i
end

.count_rows_in_partition_table(partition_name) ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 73

def count_rows_in_partition_table(partition_name)
  sql = <<~SQL
    SELECT COUNT(*) AS count
    FROM #{quoted_table(partition_name)}
  SQL
  connection.execute(sql).first["count"].to_i
end

.current_partition_lower_bound(table_name, partition_name) ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 52

def current_partition_lower_bound(table_name, partition_name)
  sql = <<~SQL
    SELECT pg_get_expr(child.relpartbound, child.oid) AS bound_expression
    FROM pg_catalog.pg_inherits inheritance
    JOIN pg_class parent ON parent.oid = inheritance.inhparent
    JOIN pg_namespace parent_namespace ON parent_namespace.oid = parent.relnamespace
    JOIN pg_class child ON child.oid = inheritance.inhrelid
    JOIN pg_namespace child_namespace ON child_namespace.oid = child.relnamespace
    WHERE parent_namespace.nspname = #{connection.quote(schema_name)}
      AND child_namespace.nspname = #{connection.quote(schema_name)}
      AND parent.relname = #{connection.quote(table_name)}
      AND child.relname = #{connection.quote(partition_name)}
  SQL

  bound_expression = connection.execute(sql).first&.fetch("bound_expression", nil)
  return if Blank.blank?(bound_expression)

  match = bound_expression.match(/FROM \('([^']+)'\)/)
  match ? Date.parse(match[1]) : nil
end

.fetch_attached_partitions(table_name) ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 98

def fetch_attached_partitions(table_name)
  sql = <<~SQL
    SELECT child.relname AS partition_name,
           pg_get_expr(child.relpartbound, child.oid) AS bound_expression
    FROM pg_catalog.pg_inherits inheritance
    JOIN pg_class parent ON parent.oid = inheritance.inhparent
    JOIN pg_namespace parent_namespace ON parent_namespace.oid = parent.relnamespace
    JOIN pg_class child ON child.oid = inheritance.inhrelid
    JOIN pg_namespace child_namespace ON child_namespace.oid = child.relnamespace
    WHERE parent_namespace.nspname = #{connection.quote(schema_name)}
      AND child_namespace.nspname = #{connection.quote(schema_name)}
      AND parent.relname = #{connection.quote(table_name)}
    ORDER BY child.relname
  SQL

  connection.execute(sql).filter_map do |row|
    parse_attached_partition(row["partition_name"], row["bound_expression"])
  end
end

.get_distinct_partition_identifiers(partition_name, partition_key_column, extract_partition_identifier) ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 195

def get_distinct_partition_identifiers(partition_name, partition_key_column, extract_partition_identifier)
  if partition_key_column.include?("::")
    base_column = partition_key_column.split("::").first.strip
    sql = <<~SQL
      SELECT DISTINCT #{partition_key_column} AS partition_key_value
      FROM #{quoted_table(partition_name)}
      WHERE #{connection.quote_column_name(base_column)} IS NOT NULL
      ORDER BY #{partition_key_column}
    SQL
  else
    sql = <<~SQL
      SELECT DISTINCT #{connection.quote_column_name(partition_key_column)} AS partition_key_value
      FROM #{quoted_table(partition_name)}
      WHERE #{connection.quote_column_name(partition_key_column)} IS NOT NULL
      ORDER BY #{connection.quote_column_name(partition_key_column)}
    SQL
  end

  connection.execute(sql).to_a.filter_map do |row|
    value = row["partition_key_value"]
    extract_partition_identifier.call(value) if Blank.present?(value)
  end.uniq
end

.parse_attached_partition(partition_name, bound_expression) ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 124

def parse_attached_partition(partition_name, bound_expression)
  return if Blank.blank?(bound_expression)

  if bound_expression == "DEFAULT"
    return AttachedPartition.new(
      name: partition_name,
      range_start: nil,
      range_end: nil,
      default: true,
      list_values: nil
    )
  end

  hash_match = bound_expression.match(/modulus (\d+), remainder (\d+)/)
  if hash_match
    return AttachedPartition.new(
      name: partition_name,
      range_start: {modulus: hash_match[1].to_i, remainder: hash_match[2].to_i},
      range_end: nil,
      default: false,
      list_values: nil
    )
  end

  list_match = bound_expression.match(/^IN \((.+)\)$/)
  if list_match
    values = list_match[1].split(",").map { |value| parse_list_value(value.strip) }
    return AttachedPartition.new(
      name: partition_name,
      range_start: values.first,
      range_end: nil,
      default: false,
      list_values: values
    )
  end

  from_match = bound_expression.match(/FROM \('([^']+)'\)/) || bound_expression.match(/FROM \((\d+)\)/)
  to_match = bound_expression.match(/TO \('([^']+)'\)/) || bound_expression.match(/TO \((\d+)\)/)
  range_end = if bound_expression.include?("MAXVALUE")
    :max
  elsif to_match
    parse_bound_value(to_match[1])
  end

  AttachedPartition.new(
    name: partition_name,
    range_start: from_match ? parse_bound_value(from_match[1]) : nil,
    range_end: range_end,
    default: false,
    list_values: nil
  )
end

.parse_bound_value(value) ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 183

def parse_bound_value(value)
  return Date.parse(value) if value.include?("-")

  value.to_i
end

.parse_list_value(value) ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 177

def parse_list_value(value)
  return nil if value.upcase == "NULL"

  value.delete_prefix("'").delete_suffix("'")
end

.partition_attached?(table_name, partition_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/partition_gardener/connection.rb', line 35

def partition_attached?(table_name, partition_name)
  sql = <<~SQL
    SELECT COUNT(*) AS count
    FROM pg_catalog.pg_inherits i
    JOIN pg_class parent ON parent.oid = i.inhparent
    JOIN pg_namespace parent_ns ON parent_ns.oid = parent.relnamespace
    JOIN pg_class child ON child.oid = i.inhrelid
    JOIN pg_namespace child_ns ON child_ns.oid = child.relnamespace
    WHERE parent_ns.nspname = #{connection.quote(schema_name)}
      AND child_ns.nspname = #{connection.quote(schema_name)}
      AND parent.relname = #{connection.quote(table_name)}
      AND child.relname = #{connection.quote(partition_name)}
  SQL

  connection.execute(sql).first["count"].to_i.positive?
end

.partition_exists?(partition_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/partition_gardener/connection.rb', line 31

def partition_exists?(partition_name)
  connection.table_exists?(partition_name)
end

.partman_parent_configured?(table_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/partition_gardener/connection.rb', line 248

def partman_parent_configured?(table_name)
  qualified_name = "#{schema_name}.#{table_name}"
  sql = <<~SQL
    SELECT 1
    FROM partman.part_config
    WHERE parent_table = #{connection.quote(qualified_name)}
    LIMIT 1
  SQL

  connection.execute(sql).any?
end

.quoted_table(name) ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 13

def quoted_table(name)
  connection.quote_table_name(name)
end

.schema_name ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 9

def schema_name
  PartitionGardener.configuration.schema_name
end

.table_is_partitioned?(table_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/partition_gardener/connection.rb', line 17

def table_is_partitioned?(table_name)
  return false unless connection.table_exists?(table_name)

  sql = <<~SQL
    SELECT COUNT(*) AS count
    FROM pg_partitioned_table pt
    JOIN pg_class c ON c.oid = pt.partrelid
    JOIN pg_namespace n ON n.oid = c.relnamespace
    WHERE n.nspname = #{connection.quote(schema_name)}
      AND c.relname = #{connection.quote(table_name)}
  SQL
  connection.execute(sql).first["count"].to_i.positive?
end

.unique_index_column_sets(table_name) ⇒ Object 



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# File 'lib/partition_gardener/connection.rb', line 219

def unique_index_column_sets(table_name)
  sql = <<~SQL
    SELECT i.indisprimary AS is_primary,
           array_agg(a.attname ORDER BY key_ord.ordinality) AS column_names
    FROM pg_index i
    JOIN pg_class table_class ON table_class.oid = i.indrelid
    JOIN pg_namespace table_namespace ON table_namespace.oid = table_class.relnamespace
    JOIN LATERAL unnest(i.indkey) WITH ORDINALITY AS key_ord(attnum, ordinality) ON true
    JOIN pg_attribute a ON a.attrelid = table_class.oid AND a.attnum = key_ord.attnum
    WHERE table_namespace.nspname = #{connection.quote(schema_name)}
      AND table_class.relname = #{connection.quote(table_name)}
      AND (i.indisunique OR i.indisprimary)
    GROUP BY i.indexrelid, i.indisprimary
  SQL

  connection.execute(sql).map do |row|
    columns = row["column_names"]
    columns = columns.gsub(/[{}]/, "").split(",") if columns.is_a?(String)
    columns
  end
end

.unique_index_covers?(table_name, conflict_key) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/partition_gardener/connection.rb', line 241

def unique_index_covers?(table_name, conflict_key)
  conflict_columns = conflict_key.map(&:to_s)
  unique_index_column_sets(table_name).any? do |index_columns|
    index_columns.first(conflict_columns.length) == conflict_columns
  end
end