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require 'shiba/index_stats'
module Shiba
class Fuzzer
def initialize(connection)
@connection = connection
end
attr_reader :connection
def fuzz!
@index_stats = fetch_index
table_sizes = guess_table_sizes
@index_stats.tables.each do |name, table|
table.count = table_sizes[name]
table.indexes.each do |name, index|
index.columns.each do |column|
column.rows_per = index.unique ? 1 : 2
end
end
end
@index_stats
end
def fetch_index
stats = Shiba::IndexStats.new
records = connection.fetch_indexes
tables = {}
records.each do |h|
h.keys.each { |k| h[k.downcase] = h.delete(k) }
h["cardinality"] = h["cardinality"].to_i
stats.add_index_column(h['table_name'], h['index_name'], h['column_name'], h['cardinality'], h['non_unique'] == 0)
end
connection.each_column_size do |table, column, size|
stats.set_column_size(table, column, size)
end
stats
end
private
BIG_FUZZ_SIZE = 100_000
SMALL_FUZZ_SIZE = 1000
# Create fake table sizes based on the table's index count.
# The more indexes, the bigger the table. Seems to rank tables fairly well.
def guess_table_sizes
index_counts = connection.count_indexes_by_table
return if index_counts.empty?
# 90th table percentile based on number of indexes
# round down so we don't blow up on small tables
large_table_idx = (index_counts.size * 0.9).floor
large_table_index_count = index_counts[large_table_idx]["index_count"].to_f
sizes = Hash[index_counts.map(&:values)]
sizes.each do |table_name, index_count|
if index_count == 0
index_count = 1
end
size = sizes[table_name]
if size >= large_table_index_count
sizes[table_name] = BIG_FUZZ_SIZE
else
sizes[table_name] = SMALL_FUZZ_SIZE
end
end
sizes
end
end
end
Version data entries
11 entries across 11 versions & 1 rubygems