In issue #5698 I raised a theory that we might have a bug when
BatchWriteItem is given two writes to the *same* key but in two different
tables. The test added here verifies that this theory was wrong, and
this case already works correctly.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20200221224221.31237-2-nyh@scylladb.com>
A previous patch fixed Alternator's writes to use the timestamp provided
by LWT instead of the current timestamp. That patch fixed the PutItem,
DeleteItem and UpdateItem operations - and this patch fixes the remaining
write operation: BatchWriteItems. So,
Fixes#5653.
Unfortunatly, the requirements of both BatchWriteItems and LWT make the
resulting code - and this patch - somewhat inelegant. BatchWriteItems
requires that we prepare all the operations first - failing if any of them
has an error. Before this patch, the result of this preparation was an
array of mutations, which in a second step we wrote to the database.
But we can no longer use mutations for the result of the first step,
because creating a mutation requires knowing the timestamp, which we don't
know during the preparate phase - we will only know it during the later
LWT operation. So now we need to invent a new intermediate format between
the request and the mutation. This intermediate format is further
complicated by the need to be send it between shards (for LWT's shard
forwarding) so it cannot, for example, contain a reference to a schema.
The fact that different sub-operations need to be sent to different shards,
and that different sub-operations may write to different tables, further
complicate the book-keeping and gives us a bunch of funky-typed maps.
But eventually it all fits together.
After this patch, as before this patch, the same code (now called
put_or_delete_item), is used to implement both the PutItem and DeleteItem
stand-alone operation, and the BachWriteItems operation which includes a
whole list of these PutItem and DeleteItem operation.
This patch also includes two more tests in test_batch.py, which test two
more corner tests we haven't tested before: One tests the capability of
BatchWriteItems to write to more than one table. The other tests that
BatchWriteItems can write an empty item (it is not surprising that it does,
but we do have special code for this case, so we should test it).
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Today, we use LWT for all PutItem, UpdateItem and GetItem operations.
We do this even for pure writes - writes which do not involve a read
before the write).
But BatchWriteItem also does pure writes - and it doesn't use LWT yet.
So this patch changes it so it does. As before we keep in the code -
not yet configurable by a user - also the option to do these unconditional
writes without LWT.
A BatchWriteItem may change multiple partitions (but a fairly low number -
DynamoDB allows each BatchWriteItem to only do 25 updates) and we start the
different LWT operations in parallel.
This patch collects multiple mutations to the same partition together to
be done with a single LWT operation, so we also add a test for this case,
were we have a batch of writes involving several items in each of several
partitions.
Fixes#5637
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20200128160538.11775-1-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>
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>
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>
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>
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>
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>
