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Contents
# Snapshot components
# http://www.postgresql.org/docs/8.3/static/functions-info.html#FUNCTIONS-TXID-SNAPSHOT-PARTS
#
# Example) 10:20:10,14,15 means xmin=10, xmax=20, xip_list=10, 14, 15.
module FlydataCore
module Postgresql
class Snapshot
include Comparable
def initialize(txid_snapshot)
@txid_snapshot_str = txid_snapshot.to_s
return if self.empty?
xmin_str, xmax_str, xip_list_str = @txid_snapshot_str.split(':')
raise ArgumentError, "Invalid snapshot - xmin is empty." if xmin_str.to_s.empty?
raise ArgumentError, "Invalid snapshot - xmax is empty." if xmax_str.to_s.empty?
@xmin = xmin_str.to_i
@xmax = xmax_str.to_i
@xip_list = xip_list_str.to_s.split(',').collect(&:to_i)
end
attr_reader :xmin, :xmax, :xip_list
def to_s
@txid_snapshot_str
end
def empty?
@txid_snapshot_str == '-'
end
def <=>(other)
return 0 if empty? && other.empty?
if self.empty? || other.empty?
raise ArgumentError.new("comparison with empty source pos failed")
end
if @xmin == other.xmin
if @xmax == other.xmax
# items xip_list will disappear after the transaction is completed,
# because xip_list is an active transaction list.
#
# The following comparison needs to be true
# "10:18:10,11,12" < "10:18:11,12"
(other.xip_list.size <=> @xip_list.size)
else
@xmax <=> other.xmax
end
else
@xmin <=> other.xmin
end
end
end
end
end
Version data entries
14 entries across 14 versions & 1 rubygems