The Query operation's conditions can be used to search for a particular
hash key or both hash and sort keys - but not any other combinations.
We previously forgot to verify most errors, so in this patch we add
missing verifications - and tests to confirm we fail the query when
DynamoDB does.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190711132720.17248-1-nyh@scylladb.com>
Add more tests for GSI - tests that DescribeTable describes the GSI,
and test the case of more than one GSI for a base table.
Unfortunately, creating an empty table with two GSIs routinely takes
on DynamoDB more than a full minute (!), so because we now have a
test with two GSIs, I had to increase the timeout in create_test_table().
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190711112911.14703-1-nyh@scylladb.com>
The holds_path() utility function is actually used to check if a value
needs read before write, so its name is changed to more fitting
check_needs_read_before_write.
Alternator currently keeps an item's attributes inside a map, and we
had a serious bug in the way we build mutations for this map:
We didn't know there was a requirement to build this mutation sorted by
the attribute's name. When we neglect to do this sorting, this confuses
Scylla's merging algorithms, which assume collection cells are thus
sorted, and the result can be duplicate cells in a collection, and the
visible effect is a mutation that seems to be ignored - because both
old and new values exist in the collection.
So this patch includes a new helper class, "attribute_collector", which
helps collect attribute updates (put and del) and extract them in correctly
sorted order. This helper class also eliminates some duplication of
arcane code to create collection cells or deletions of collection cells.
This patch includes a simple test that previously failed, and one xfail
test that failed just because of this bug (this was the test that exposed
this bug). Both tests now succeed.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190709160858.6316-1-nyh@scylladb.com>
This patch adds what is hopefully an exhaustive test suite for the
global secondary indexing (GSI) feature, and all its various
complications and corner cases of how GSIs can be created, deleted,
named, written, read, and more (the tests are heavily documented to
explain what they are testing).
All these tests pass on DynamoDB, and fail on Alternator, so they are
marked "xfail". As we develop the GSI feature in Alternator piece by
piece, we should make these tests start to pass.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190708160145.13865-1-nyh@scylladb.com>
This adds another test for BatchWriteItem: That if one of the operations is
invalid - e.g., has a wrong key type - the entire batch is rejected, and not
none of its operations are done - even the valid ones.
The test succeeds, because we already handle this case correctly.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190707134610.30613-1-nyh@scylladb.com>
Test an operation like SET #one = #two, where the RHS has a reference
to a name, rather than the name itself. Also verify that DynamoDB
gives an error if ExpressionAttributeNames includes names not needed
by neither left or right hand side of such assignments.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190708133311.11843-1-nyh@scylladb.com>
In order to serve update requests that depend on read-before-write,
a proper helper function which fetches the existing item with a given
key from the database is added.
This read-before-write mechanism is not considered safe, because it
provides no linearizability guarantees and offers no synchronization
protection. As such, it should be consider a placeholder that works
fine on a single machine and/or no concurrent access to the same key.
The calculate_value utility function is going to need more context
in order to resolve paths present in the right-hand side of update_item
operators: update_info and schema.
Historically, resolving a path checked for key columns, which are not
allowed to be on the left-hand side of the assignment. However, path
resolving will now also be used for right-hand side, where it should
be allowed to use the key value.
In order to implement read-before-write in the future, calculate_value
now accepts an additional parameter: previous_item. If read-before-write
was performed, previous_item will contain an item for the given key
which already exists in the database at the time of the update.
This patch moves the create_test_table() utility function, which creates
a test table with a unique name, from the fixtures (conftest.py) to
util.py. This will allow reusing this function in tests which need to
create tables but not through the existing fixtures. In particular
we will need to do this for GSI (global secondary index) tests
in the next patch.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190708104438.5830-1-nyh@scylladb.com>
The tests we had for BatchWriteItem's refusal to accept duplicate keys
only used test_table_s, with just a hash key. This patch adds tests
for test_table, i.e., a table with both hash and sort keys - to check
that we check duplicates in that case correctly as well.
Moreover, the expanded tests also verify that although identical
keys are not allowed, keys with just one component (hash or sort key)
the same but the other not the same - are fine.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190705191737.22235-1-nyh@scylladb.com>
Even when running against a local Alternator, Boto3 wants to know the
region name, and AWS credentials, even though they aren't actually needed.
For a local run, we can supply garbage values for these settings, to
allow a user who never configured AWS to run tests locally.
Running against "--aws" will, of course, still require the user to
configure AWS.
Also modified the README to be clearer, and more focused on the local
runs.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190708121420.7485-1-nyh@scylladb.com>
For "--aws" tests, use the default region chosen by the user in the
AWS configuration (~/.aws/config or environment variable), instead of
hard-coding "us-east-1".
Patch by Pekka Enberg.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190708105852.6313-1-nyh@scylladb.com>
Calculating value represented as 'v1 + v2' or 'v1 - v2' was previously
implemented with a double type, which offers limited precision.
From now on, these computations are based on big_decimal, which
allows returning values without losing precision.
This patch depends on 'add big_decimal arithmetic operators' series.
Message-Id: <f741017fe3d3287fa70618068bdc753bfc903e74.1562318971.git.sarna@scylladb.com>
Move some common utility functions to a common file "util.py"
instead of repeating them in many test files.
The utility functions include random_string(), random_bytes(),
full_scan(), full_query(), and multiset() (the more general
version, which also supports freezing nested dicts).
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190705081013.1796-1-nyh@scylladb.com>
The idiomatic way to use an std::variant depending the type holds is to use
std::visit. This modern API makes it unnecessary to write many boiler-plate
functions to test and cast the type of the variant, and makes it impossible
to forget one of the options. So in this patch we throw out the old ways,
and welcome the new.
Thanks to Piotr Sarna for the idea.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190704205625.20300-1-nyh@scylladb.com>
This patch adds to Alternator an implementation of the BatchGetItem
operation, which allows to start a number of GetItem requests in parallel
in a single request.
The implementation is almost complete - the only missing feature is the
ability to ask only for non-top-level attributes in ProjectionExpression.
Everything else should work, and this patch also includes tests which,
as usual, pass on DynamoDB and now also on Alternator.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Amazingly, it appears we never tested booting Alternator a second time :-)
Our initialization code creates a new keyspace, and was supposed to ignore
the error if this keyspace already existed - but we thought the error will
come as an exceptional future, which it didn't - it came as a thrown
exception. So we need to change handle_exception() to a try/catch.
With this patch, I can kill Alternator and it will correctly start again.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Operations which take a key as parameter, namely GetItem, UpdateItem,
DeleteItem and BatchWriteItem's DeleteRequest, already fail if the given
key is missing one of the nessary key attributes, or has the wrong types
for them. But they should also fail if the given key has spurious
attributes beyond those actually needed in a key.
So this patch adds this check, and tests to confirm that we do these checks
correctly.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
The PutItem operation, and also the PutRequest of BatchWriteItem, are
supposed to completely replace the item - not to merge the new value with
the previous value. We implemented this wrongly - we just wrote the new
item forgetting a tombstone to remove the old item.
So this patch fixes these operations, and adds tests which confirm the
fix (as usual, these tests pass on DynamoDB, failed on Alternator before
this patch, and pass after the patch).
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Add support for the DeleteItem operation, which deletes an item.
The basic deletion operation is supported. Still not supported are:
1. Parameters to conditionally delete (ConditionalExpression or Expected)
2. Parameters to return pre-delete content
3. ReturnItemCollectionMetrics (statistics relevant for tables with LSI)
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
In BatchWriteItem, we currently only support the PutRequest operation.
If a user tries to use DeleteRequest (which we don't support yet), he
will get a bizarre error. Let's test the request type more carefully,
and print a better error message. This will also be the place where
eventually we'll actually implement the DeleteRequest.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This patch adds more comprehensive tests for the BatchWriteItem operation,
in a new file batch_test.py. The one test we already had for it was also
moved from test_item.py here.
Some of the test still xfail for two reasons:
1. Support for the DeleteRequest operation of BatchWriteItem is missing.
2. Tests that forbid duplicate keys in the same request are missing.
As usual, all tests succeed on DynamoDB, and hopefully (I tried...)
cover all the BatchWriteItem features.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
DynamoDB has two similar parameters - AttributesToGet and
ProjectionExpression - which are supported by the GetItem, Scan and
Query operations. Until now we supported only the older AttributesToGet,
and this patch adds support to the newer ProjectionExpression.
Besides having a different syntax, the main difference between
AttributesToGet and ProjectionExpression is that the latter also
allows fetching only a specific nested attribute, e.g., a.b[3].c.
We do not support this feature yet, although it would not be
hard to add it: With our current data representation, it means
fetching the top-level attribute 'a', whose value is a JSON, and then
post-filtering it to take out only the '.b[3].c'. We'll do that
later.
This patch also adds more test cases to test_projection_expression.py.
All tests except three which check the nested attributes now pass,
and those three xfail (they succeed on DynamoDB, and fail as expected
on Alternator), reminding us what still needs to be done.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Our GetItem, Query and Scan implementations support the AttributesToGet
parameter to fetch only a subset of the attributes, but we don't yet
support the more elaborate ProjectionExpression parameter, which is
similar but has a different syntax and also allows to specify nested
document paths.
This patch adds existive testing of all the ProjectionExpression features.
All these tests pass against DynamoDB, but fail against the current
Alternator so they are marked "xfail". These tests will be helpful for
developing the ProjectionExpression feature.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
The AttributesToGet parameter - saying which attributes to fetch for each
item - is already supported in the GetItem, Query and Scan operations.
However, we only had a test for it for it for Scan. This patch adds
similar tests also for the GetItem and Query operations.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Yet another test for overwriting a top-level attribute which contains
a nested document - here, overwriting it by just a string.
This test passes. In the current implementation we don't yet support
updates to specific attribute paths (e.g. a.b[3].c) but we do support
well writing and over-writing top-level attributes.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This patch implements the last (finally!) syntactic feature of the
UpdateExpression - the ability to do SET a=val1+val2 (where, as
before, each of the values can be a reference to a value, an
attribute path, or a function call).
The implementation is not perfect: It adds the values as double-precision
numbers, which can lose precision. So the patch adds a new test which
checks that the precision isn't lost - a test that currently fails
(xfail) on Alternator, but passes on DynamoDB. The pre-existing test
for adding small integer now passes on Alternator.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
In the previous patch we added function-call support in the UpdateExpression
parser. In this patch we add support for one such function - list_append().
This function takes two values, confirms they are lists, and concatenates
them. After this patch only one function remains unimplemented:
if_not_exists().
We also split the test we already had for list_append() into two tests:
One uses only value references (":val") and passes after this patch.
The second test also uses references to other attributes and will only
work after we start supporting read-modify-write.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Until this patch, in update expressions like "SET a = :val", we only
allowed the right-hand-side of the assignment to be a reference to a
value stored in the request - like ":val" in the above example.
But DynamoDB also allows the value to be an attribute path (e.g.,
"a.b[3].c", and can also be a function of a bunch of other values.
This patch adds supports for parsing all these value types.
This patch only adds the correct parsing of these additional types of
values, but they are still not supported: reading existing attributes
(i.e., read-modify-write operations) is still not supported, and
none of the two functions which UpdateExpression needs to support
are supported yet. Nevertheless, the parsing is now correct, and the
the "unknown_function" test starts to pass.
Note that DynamoDB allows the right-hand side of an assignment to be
not only a single value, but also value+value and value-value. This
possibility is not yet supported by the parser and will be added
later.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
The test cases verify that equality-based filtering on non-key
attributes works fine. It also contains test stubs for key filtering
and non-equality attribute filtering.
