Class: Taps::DataStreamKeyed
Constant Summary
Constants inherited
from DataStream
Taps::DataStream::DEFAULT_CHUNKSIZE
Instance Attribute Summary collapse
Attributes inherited from DataStream
#db, #state
Instance Method Summary
collapse
Methods inherited from DataStream
#complete?, #encode_rows, #error, #error=, factory, #fetch, #fetch_chunksize, #fetch_from_resource, #fetch_remote, #fetch_remote_in_server, #log, #max_chunksize_training, #order_by, #parse_encoded_data, parse_json, #string_columns, #table, #table_name, #table_name_sql, #to_hash, #to_json, #update_chunksize_stats, #verify_remote_stream
Constructor Details
Returns a new instance of DataStreamKeyed.
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# File 'lib/taps/data_stream.rb', line 248
def initialize(db, state)
super(db, state)
@state = { primary_key: order_by(state[:table_name]).first, filter: 0 }.merge(state)
@state[:chunksize] ||= DEFAULT_CHUNKSIZE
@buffer = []
end
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Instance Attribute Details
#buffer ⇒ Object
Returns the value of attribute buffer.
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# File 'lib/taps/data_stream.rb', line 246
def buffer
@buffer
end
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Instance Method Details
#buffer_limit ⇒ Object
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# File 'lib/taps/data_stream.rb', line 259
def buffer_limit
if state[:last_fetched] && (state[:last_fetched] < state[:filter]) && buffer.empty?
state[:last_fetched]
else
state[:filter]
end
end
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#calc_limit(chunksize) ⇒ Object
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# File 'lib/taps/data_stream.rb', line 267
def calc_limit(chunksize)
if defined?(Sinatra)
(chunksize * 1.1).ceil
else
(chunksize * 3).ceil
end
end
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#fetch_buffered(chunksize) ⇒ Object
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# File 'lib/taps/data_stream.rb', line 299
def fetch_buffered(chunksize)
load_buffer(chunksize) if self.buffer.size < chunksize
rows = buffer.slice(0, chunksize)
state[:last_fetched] = (rows.last[primary_key] unless rows.empty?)
rows
end
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#fetch_rows ⇒ Object
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# File 'lib/taps/data_stream.rb', line 310
def fetch_rows
chunksize = state[:chunksize]
Taps::Utils.format_data(fetch_buffered(chunksize) || [],
string_columns: string_columns)
end
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#import_rows(rows) ⇒ Object
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# File 'lib/taps/data_stream.rb', line 306
def import_rows(rows)
table.import(rows[:header], rows[:data])
end
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#increment(row_count) ⇒ Object
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# File 'lib/taps/data_stream.rb', line 316
def increment(row_count)
@buffer.slice!(0, row_count)
end
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#load_buffer(chunksize) ⇒ Object
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# File 'lib/taps/data_stream.rb', line 278
def load_buffer(chunksize)
num = 0
loop do
limit = calc_limit(chunksize)
key = primary_key
buf_limit = buffer_limit
ds = table.order(*order_by).filter { key.sql_number > buf_limit }.limit(limit)
log.debug "DataStreamKeyed#load_buffer SQL -> #{ds.sql}"
data = ds.all
self.buffer += data
num += data.size
unless data.empty?
state[:filter] = self.buffer.last[primary_key]
end
break if (num >= chunksize) || data.empty?
end
end
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#primary_key ⇒ Object
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# File 'lib/taps/data_stream.rb', line 255
def primary_key
state[:primary_key].to_sym
end
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#verify_stream ⇒ Object
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# File 'lib/taps/data_stream.rb', line 321
def verify_stream
key = primary_key
ds = table.order(*order_by)
current_filter = ds.max(key.sql_number)
state[:filter] = current_filter
state[:last_fetched] = nil
log.debug "DataStreamKeyed#verify_stream -> state: #{state.inspect}"
end
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