DynamoDB complains, and fails an update, if the update contains in
ExpressionAttributeNames or ExpressionAttributeValues names which aren't
used by the expression.
Let's do the same, although sadly this means more work to track which
of the references we've seen and which we haven't.
This patch makes two previously xfail (expected fail) tests become
successful tests on Alternator (they always succeeded against DynamoDB).
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
For the UpdateItem operation, so far we supported updates via the
AttributeUpdates parameter, specifying which attributes to set or remove
and how. But this parameter is considered deprecated, and DynamoDB supports
a more elaborate way to modify attributes, via an "UpdateExpression".
In the previous patch we added a function to parse such an UpdateExpression,
and in this patch we use the result of this parsing to actually perform
the required updates.
UpdateExpression is only partially supported after this patch. The basic
"SET" and "REMOVE" operations are supported, but various other cases aren't
fully supported and will be fixed in followup patches. The following
patch will add extensive tests to confirm exactly what works correctly
with the new UpdateExpression support.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Attributes for reads (GetItem, Query, Scan, ...) and writes (PutItem,
UpdateItem, ...) are now serialized and deserialized in binary form
instead of raw JSON, provided that their type is S, B, BOOL or N.
Optimized serialization for the rest of the types will be introduced
as follow-ups.
Message-Id: <6aa9979d5db22ac42be0a835f8ed2931dae208c1.1559646761.git.sarna@scylladb.com>
So far for UpdateItem we only supported the old-style AttributeUpdates
parameter, not the newer UpdateExpression. This patch begins the path
to supporting UpdateExpression. First, trying to use *both* parameters
should result in an error, and this patch does this (and tests this).
Second, passing neither parameters is allowed, and should result in
an *empty* item being created.
Finally, since today we do not yet support UpdateExpression, this patch
will cause UpdateItem to fail if UpdateExpression is used, instead of
silently being ignored as we did so far.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Remove the incomplete and unused function to convert DynamoDB type names
to ScyllaDB type objects:
DynamoDB has a different set of types relevant for keys and for attributes.
We already have a separate function, parse_key_type(), for parsing key
types, and for attributes - we don't currently parse the type names at
all (we just save them as JSON strings), so the function we removed here
wasn't used, and was in fact #if'ed out. It was never completed, and it now
started to decay (the type for numbers is wrong), so we're better off
completely removing it.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This patch implements a fully working number type for keys, and now
Alternator fully and correctly supports every key type - strings, byte
arrays, and numbers.
The patch also adds a test which verifies that Scylla correctly sorts
number sort keys, and also correctly retrieves them to the full precision
guaranteed by DynamoDB (38 decimal digits).
The implementation uses Scylla's "decimal" type, which supports arbitrary
precision decimal floating point, and in particular supports the precision
specified by DynamoDB. However, "decimal" is actually over-qualified for
this use, so might not be optimal for the more specific requirements of
DynamoDB. So a FIXME is left to optimize this case in the future.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Until now we only supported string for key columns (hash or sort key).
This patch adds support for the bytes type (a.k.a binary or blob) as well.
The last missing type to be supported in keys is the number type.
Note that in JSON, bytes values are represented with base64 encoding,
so we need to decode them before storing the decoded value, and re-encode
when the user retrieves the value. The decoding is important not just
for saving storage space (the encoding is 4/3 the size of the decoded)
but also for correct *sorting* of the binary keys.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
BEGINS_WITH statement increments a string in order to compute
the upper bound for a clustering range of a query.
Unfortunately, previous implementation was not correct,
as it appended a <0> byte if the last character was <255>,
instead of incrementing a last-but-one character.
If the string contains <255> bytes only, the upper bound
of the returned upper bound is infinite.
Message-Id: <3a569f08f61fca66cc4f5d9e09a7188f6daad578.1558524028.git.sarna@scylladb.com>
We had several places in the code that need to parse the
ConsistentRead flag in the request. Let's add a function
that does this, and while at it, checks for more error
cases and also returns LOCAL_QUORUM and LOCAL_ONE instead
of QUORUM and ONE.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
As Shlomi suggested in the past, it is more likely that when we
eventually support global tables, we will use LOCAL_QUORUM,
not QUORUM. So let's switch to that now.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
When a table has a hash key or sort key of a certain type (this can
be string, bytes, or number), one cannot try to choose an item using
values of different types.
We previously did not handle this case gracefully, and PutItem handled
it particularly bad - writing malformed data to the sstable and basically
hanging Scylla. In this patch we fix the pk_from_json() and ck_from_json()
functions to verify the expected type, and fail gracefully if the user
sent the wrong type.
This patch also adds tests for these failures, for the GetItem, PutItem,
and UpdateItem operations.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
According to the documentation, trying to GetItem a non-existant item
should result in an empty response - NOT a response with an empty "Item"
map as we do before this patch.
This patch fixes this case, and adds a test case for it. As usual,
we verify that the test case also works on Amazon DynamoDB, to verify
DynamoDB really behaves the way we thik it does.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
If an empty item (i.e., no attributes except the key) is created, or an item
becomes empty (by deleting its existing attributes), the empty item must be
maintained - it cannot just disappear. To do this in Scylla, we must add a
row marker - otherwise an empty attribute map is not enough to keep the
row alive.
This patch includes 4 test cases for all the various ways an empty item can be
created empty or non-empty item be emptied, and verifies that the empty item
can be correctly retrieved (as usual, to verify that our expectation of
"correctness" is indeed correct, we run the same tests against DynamoDB).
All these 4 tests failed before this patch, and now succeed.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
These lines of codes were superfluous and their result unused: the
make_item_mutation() function finds the pk and ck on its own.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
his patch adds a statistics framework to Alternator: Executor has (for
each shard) a _stats object which contains counters for various events,
and also is in charge of making these counters visible via Scylla's regular
metrics API (http://localhost:9180/metrics).
This patch includes a counter for each of DynamoDB's operation types,
and we increase the ones we support when handled. We also added counters
for total operations and unsupported operations (operation types we don't
yet handle). In the future we can easily add many more counters: Define
the counter in stats.hh, export it in stats.cc, and increment it in
where relevant in executor.cc (or server.cc).
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
When a Scan selects only certain attributes, and none of the key
attributes are selected, for some of the scanned items *nothing*
will remain to be output, but still Dynamo outputs an empty item
in this case. Our code had a bug where after each item we "moved"
the object leaving behind a null object, not an empty map, so a
completely empty item wasn't output as an empty map as expected,
and resulted in boto3 failing to parse the response.
This simple one-line patch fixes the bug, by resetting the item
to an empty map after moving it out.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Instead of blindly returning "localhost:8000" in response to
DescribeEndpoints and for sure causing us problems in the future,
the right thing to do is to return the same domain name which the
user originally used to get to us, be it "localhost:8000" or
"some.domain.name:1234". But how can we know what this domain name
was? Easy - this is why HTTP 1.1 added a mandatory "Host:" header,
and the DynamoDB driver I tested (boto3) adds it as expected,
indeed with the expected value of "localhost:8000" on my local setup.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Because of a typo, we incorrectly set the table's sort key as a second
partition key column instead of a clustering key column. This has bad
but subtle consequences - such as that the items are *not* sorted
according to the sort key. So in this patch we fix the typo.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
DescribeEndpoints is not a very important API (and by default, clients
don't use it) but I wanted to understand how DynamoDB responds to it,
and what better way than to write a test :-)
And then, if we already have a test, let's implement this request in
Scylla as well. This is a silly implementation, which always returns
"localhost:8000". In the future, this will need to be configurable -
we're not supposed here to return *this* server's IP address, but rather
a domain name which can be used to get to all servers.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Most of the request types need to a TableName parameter, specifying the
name of the table they operate on. There's a lot of boilerplate code
required to get this table name and verify that it is valid (the parameter
exists, is a string, passes DynamoDB's naming rules, and the table
actually exists), which resulted in a lot of code duplication - and
in some cases missing checks.
So this patch introduces two utility functions, get_table_name()
and get_table(), to fetch a table name or the schema of an existing
table, from the request, with all necessary validation. If validation
fails, the appropriate api_error() is thrown so the user gets the
right error message.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
The ck_from_json() utility function is easier to use if it handles
the no-clustering-key case as the callers need them too, instead of
requiring them to handle the no-clustering-key case separately.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
So far we supported UpdateItem only with PUT operations - this patch
adds support for DELETE operations, to delete specific attributes from
an item.
Only the case of a missing value is support. DynamoDB also provides
the ability to pass the old value, and only perform the deletion if
the value and/or its type is still up-to-date - but we don't support
this yet and fail such request if it is attempted.
This patch also includes a test for this case in alternator-test/
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Add an initial UpdateItem implementation. As PutItem and GetItem we
are still limited to string attributes. This initial implementation
of UpdateItem implements only the "PUT" action (not "DELETE" and
certainly not "ADD") and not any of the more advanced options.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
All operation-generated error messages should have the 400 HTTP error
code. It's a real nag to have to type it every time. So make it the
default.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Without special options, PutItem should return nothing (an empty
JSON result). Previously we had trouble doing this, because instead
of return an empty JSON result, we converted an empty string into
JSON :-) So the existing code had an ugly workaround which worked,
sort of, for the Python driver but not for the Java driver.
The correct fix, in this patch, is to invent a new type json_string
which is a string *already* in JSON and doesn't need further conversion,
so we can use it to return the empty result. PutItem now works from
YCSB's Java driver.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Although we would like to allow table names up to 222 bytes, this is not
currently possible because Scylla tacks additional 33 bytes to create
a directory name, and directory names are limited to 255 bytes.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
The supported key types are just S(tring), B(lob), or N(umber).
Other types are valid for attributes, but not for keys, and should
not be accepted. And wrong types used should result in the appropriate
user-visible error.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
To be correct, CreateTable's input parsing need to work in reverse from
what it did: First, the key columns are listed in KeySchema, and then
each of these (and potetially more, e.g., from indexes) need to appear
AttributeDefinitions.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Without any arguments, PutItem should return no data at all. But somehow,
for reasons I don't understand, the boto3 driver gets confused from an
empty JSON thinking it isn't JSON at all. If we return a structure with
an empty "attributes" fields, boto3 is happy.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Add an initial implementation of Delete table, enough for making the
pytest --local test_table.py::test_create_and_delete_table
Pass.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
The structure's name in DescribeTable's output is supposed to be called
"Table", not "TableDescription". Putting in the wrong place caused the
driver's table creation waiters to fail.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
validate table name in CreateTable, and if it doesn't fit DynamoDB's
requirement, return the appropriate error as drivers expect.
With this patch, test_table.py::test_create_table_unsupported_names
now passes (albeit with a one minute pause - this a bug with keep-alive
support...).
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This initial implementation is enough to pass a test of getting a
failure for a non-existant table -
test_table.py::test_describe_table_non_existent_table
and to recognize an existing table. But it's still missing a lot
of fields for an existing table (among others, the schema).
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
