def test_query_filter_paging(test_table_sn_with_data):
table, p, items = test_table_sn_with_data
# Filter on the "bool" attribute so the filter will match roughly half of
# the items.
(prefilter_count, postfilter_count, pages,
got_items) = full_query_and_counts(table,
KeyConditions={
'p': {
'AttributeValueList': [p],
'ComparisonOperator': 'EQ'
}
},
QueryFilter={
'bool': {
'AttributeValueList': [True],
'ComparisonOperator': 'EQ'
}
},
Limit=1)
expected_items = [item for item in items if item['bool'] == True]
assert (got_items == expected_items)
# We expect the number of pages to be len(items)+1. The "+1" is because
# the 20th page found one last item to consider (it may or may not have
# passed the filter), but doesn't know it is really the last item - it
# takes one more query to discover there are no more.
assert (pages == len(items) + 1)
def test_query_filter_paging(test_table_sn_with_data):
table, p, items = test_table_sn_with_data
# Filter on the "bool" attribute so the filter will match roughly half of
# the items.
(prefilter_count, postfilter_count, pages,
got_items) = full_query_and_counts(table,
KeyConditions={
'p': {
'AttributeValueList': [p],
'ComparisonOperator': 'EQ'
}
},
QueryFilter={
'bool': {
'AttributeValueList': [True],
'ComparisonOperator': 'EQ'
}
},
Limit=1)
expected_items = [item for item in items if item['bool'] == True]
assert (got_items == expected_items)
# The total number of pages may be len(items) or len(items)+1, depending
# on the implementation: The "+1" can happen if the 20th page found one
# last item to consider (it may or may not have passed the filter), but
# doesn't know it is really the last item - it may take one more query to
# discover there are no more. Currently, Alternator returns len(items)+1
# while DynamoDB returns len(items), but neither is more correct than the
# other - nor should any user case about this difference, as empty pages
# are a documented possibility.
assert (pages == len(items) or pages == len(items) + 1)
def test_query_filter_and_select_count(test_table):
p = random_string()
test_table.put_item(Item={'p': p, 'c': 'hi', 'x': 'dog', 'y': 'cat'})
test_table.put_item(Item={'p': p, 'c': 'yo', 'x': 'mouse', 'y': 'horse'})
(prefilter_count, postfilter_count, pages,
got_items) = full_query_and_counts(test_table,
KeyConditions={
'p': {
'AttributeValueList': [p],
'ComparisonOperator': 'EQ'
}
},
QueryFilter={
'x': {
'AttributeValueList':
['mouse'],
'ComparisonOperator': 'EQ'
}
},
Select='COUNT')
# Exactly one item matches the filter on x. But because of Select=COUNT,
# we shouldn't get an item back - just the count.
assert postfilter_count == 1
assert prefilter_count == 2
assert got_items == []
def test_filter_expression_and_select_count(test_table):
p = random_string()
test_table.put_item(Item={'p': p, 'c': 'hi', 'x': 'dog', 'y': 'cat'})
test_table.put_item(Item={'p': p, 'c': 'yo', 'x': 'mouse', 'y': 'horse'})
(prefilter_count, postfilter_count, pages, got_items) = full_query_and_counts(test_table,
KeyConditionExpression='p=:p',
FilterExpression='x=:x',
Select='COUNT',
ExpressionAttributeValues={':p': p, ':x': 'mouse'})
# Exactly one item matches the filter on x. But because of Select=COUNT,
# we shouldn't get an item back - just the count.
assert postfilter_count == 1
assert prefilter_count == 2
assert got_items == []
def test_query_filter_counts(test_table_sn_with_data):
table, p, items = test_table_sn_with_data
# First test without a filter - both Count (postfilter_count) and
# ScannedCount (prefilter_count) should return the same count of items.
(prefilter_count, postfilter_count, pages,
got_items) = full_query_and_counts(table,
KeyConditions={
'p': {
'AttributeValueList': [p],
'ComparisonOperator': 'EQ'
}
})
assert (got_items == items)
assert (prefilter_count == len(items))
assert (postfilter_count == len(items))
# Now use a filter, on the "bool" attribute so the filter will match
# roughly half of the items. ScannedCount (prefilter_count) should still
# returns the full number of items, but Count (postfilter_count) returns
# should return just the number of matched items.
(prefilter_count, postfilter_count, pages,
got_items) = full_query_and_counts(table,
KeyConditions={
'p': {
'AttributeValueList': [p],
'ComparisonOperator': 'EQ'
}
},
QueryFilter={
'bool': {
'AttributeValueList': [True],
'ComparisonOperator': 'EQ'
}
})
expected_items = [item for item in items if item['bool'] == True]
assert (got_items == expected_items)
assert (prefilter_count == len(items))
assert (postfilter_count == len(expected_items))
