`duration` is a new native type that was introduced in Cassandra 3.10 [1].
Support for parsing and the internal representation of the type was added in
8fa47b74e8.
Important note: The version of cqlsh distributed with Scylla does not have
support for durations included (it was added to Cassandra in [2]). To test this
change, you can use cqlsh distributed with Cassandra.
Duration types are useful when working with time-series tables, because they can
be used to manipulate date-time values in relative terms.
Two interesting applications are:
- Aggregation by time intervals [3]:
`SELECT * FROM my_table GROUP BY floor(time, 3h)`
- Querying on changes in date-times:
`SELECT ... WHERE last_heartbeat_time < now() - 3h`
(Note: neither of these is currently supported, though columns with duration
values are.)
Internally, durations are represented as three signed counters: one for months,
for days, and for nanoseconds. Each of these counters is serialized using a
variable-length encoding which is described in version 5 of the CQL native
protocol specification.
The representation of a duration as three counters means that a semantic
ordering on durations doesn't exist: Is `1mo` greater than `1mo1d`? We cannot
know, because some months have more days than others. Durations can only have a
concrete absolute value when they are "attached" to absolute date-time
references. For example, `2015-04-31 at 12:00:00 + 1mo`.
That duration values are not comparable presents some difficulties for the
implementation, because most CQL types are. Like in Cassandra's implementation
[2], I adopted a similar strategy to the way restrictions on the `counter` type
are checked. A type "references" a duration if it is either a duration or it
contains a duration (like a `tuple<..., duration, ...>`, or a UDT with a
duration member).
The following restrictions apply on durations. Note that some of these contexts
are either experimental features (materialized views), or not currently
supported at run-time (though support exists in the parser and code, so it is
prudent to add the restrictions now):
- Durations cannot appear in any part of a primary key, either for tables or
materialized views.
- Durations cannot be directly used as the element type of a `set`, nor can they
be used as the key type of a `map`. Because internal ordering on durations is
based on a byte-level comparison, this property of Cassandra was intended to
help avoid user confusion around ordering of collection elements.
- Secondary indexes on durations are not supported.
- "Slice" relations (<=, <, >=, >) are not supported on durations with `WHERE`
restrictions (like `SELECT ... WHERE span <= 3d`). Multi-column restrictions
only work with clustering columns, which cannot be `duration` due to the
first rule.
- "Slice" relations are not supported on durations with query conditions (like
`UPDATE my_table ... IF span > 5us`).
Backwards incompatibility note:
As described in the documentation [4], duration literals take one of two
forms: either ISO 8601 formats (there are three), or a "standard" format. The ISO
8601 formats start with "P" (like "P5W"). Therefore, identifiers that have this
form are no longer supported.
Fixes#2240.
[1] https://issues.apache.org/jira/browse/CASSANDRA-11873
[2] bfd57d13b7
[3] https://issues.apache.org/jira/browse/CASSANDRA-11871
[4] http://cassandra.apache.org/doc/latest/cql/types.html#working-with-durations
This patch provides a rather trivial implementation of hash() for
collection types.
It is needed for view building, where we hold mutations in a map
indexed by partition keys (and frozen collection types can be part of
the key).
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20170718192107.13746-1-duarte@scylladb.com>
Currently each time UDT or tuple is parsed new object is created. If
those objects are used to create container type repeatedly it will cause
memory leak since container types are interned, but lookup in the
cache is done using pointer to a contained type (which will be always
different for UDT and tuples). This patches interns also UDT and tuple,
so each type the same object is parsed same pointer is also returned.
Refs #2469Fixes#2487
Message-Id: <20170612142942.GO21915@scylladb.com>
"Defines origin v3-format for system/schema tables, and use them for
schema storage/retrival.
Includes a legacy_schema_migrator implementation/port from origin. Note
that since we don't support features like triggers, functions and
aggregates, it will bail if encountering such a feature used.
Note also that this patch set does not convert the "hints" and
"backlog" tables, even though these have changed in v3 as well.
That will be a separate patch set.
Tested against dtests. Note that patches for dtest + ccm
will follow."
* 'calle/systemtables' of github.com:cloudius-systems/seastar-dev: (36 commits)
legacy_schema_migrator: Actually truncate legacy schema tables on finish
database: Extract "remove" from "drop_columnfamily"
v3 schema test fixes
thrift: Update CQL mapping of static CFs
schema_tables: Use v3 schema tables and formats
type_parser: Origin expects empty string -> bytes_type
cf_prop_defs: Add crc_check_chance as recognized (even if we don't use)
types_test: v3 style schemas enforce explicit "frozen" in tupes/ut:s
cql3_type: v3 to_string
cql_types: Introduce cql3_type::empty and associate with empty data_type
schema: rename column accessors to be in line with origin
schema: Add "is_static_compact_table"
schema_builder: Add helper to generate unique column names akin origin
schema: Add utility functions for static columns
schema: Use heterogeneous comparator for columns bounds
cql3_type_parser: Resolve from cql3 names/expressions
cql3_type: Add "prepare_interal" and "references_user_type"
cql3::cql3_type: Add prepare_internal path using only "local" holders
cql3_type: Add virtual destructor.
database/main: encapsulate system CF dir touching
...
The standard serialization API (e.g. in data_value) includes the following methods:
size_t serialized_size() const;
void serialize(bytes::iterator& it) const;
bytes serialize() const;
Align the utils::UUID API with the pattern above.
The only addition is that we are going to make an output iterator parameter of a second method above
a template so that we may serialize into different output sources.
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
This patch replaces the current row tombstone representation by a
row_tombstone.
The intent of the patch is thus to reify the idea of shadowable
tombstones, that up until now we considered all materialized view row
tombstones to be.
We need to distinguish shadowable from non-shadowable row tombstones
to support scenarios such as, when inserting to a table with a
materialzied view:
1. insert into base (p, v1, v2) values (3, 1, 3) using timestamp 1
2. delete from base using timestamp 2 where p = 3
3. insert into base (p, v1) values (3, 1) using timestamp 3
These should yield a view row where v2 is definitely null, but with
the current implementation, v2 will pop back with its value v2=3@TS=1,
even though its dead in the base row. This is because the row
tombstone inserted at 2) is a shadowable one.
This patch only addresses the memory representation of such
row_tombstones.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
When compacting a fully expired sstable, we're not allowing that sstable
to be purged because expired cell is *unconditionally* converted into a
dead cell. Why not check if the expired cell can be purged instead using
gc before and max purgeable timestamp?
Currently, we need two compactions to get rid of a fully expired sstable
which cells could have always been purged.
look at this sstable with expired cell:
{
"partition" : {
"key" : [ "2" ],
"position" : 0
},
"rows" : [
{
"type" : "row",
"position" : 120,
"liveness_info" : { "tstamp" : "2017-04-09T17:07:12.702597Z",
"ttl" : 20, "expires_at" : "2017-04-09T17:07:32Z", "expired" : true },
"cells" : [
{ "name" : "country", "value" : "1" },
]
now this sstable data after first compaction:
[shard 0] compaction - Compacted 1 sstables to [...]. 120 bytes to 79
(~65% of original) in 229ms = 0.000328997MB/s.
{
...
"rows" : [
{
"type" : "row",
"position" : 79,
"cells" : [
{ "name" : "country", "deletion_info" :
{ "local_delete_time" : "2017-04-09T17:07:12Z" },
"tstamp" : "2017-04-09T17:07:12.702597Z"
},
]
now another compaction will actually get rid of data:
compaction - Compacted 1 sstables to []. 79 bytes to 0 (~0% of original)
in 1ms = 0MB/s. ~2 total partitions merged to 0
NOTE:
It's a waste of time to wait for second compaction because the expired
cell could have been purged at first compaction because it satisfied
gc_before and max purgeable timestamp.
Fixes#2249, #2253
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20170413001049.9663-1-raphaelsc@scylladb.com>
This patch fixes collection_type_impl::difference() so it does set
difference for tombstones instead of just returning the larger
one, as difference() is supposed to return only the information in
mutation A that supersedes that in B, given difference(A, B).
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch changes the collection_type_impl::is_empty() function so
that it doesn't consider empty a collection_mutation which has a
tombstone.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Support for deletion of counters is limited in a way that once deleted
they cannot be used again (i.e. tombstone always wins, regardless of the
timestamp). Logic responsible for merging two counter cells already
makes sure that tombstones are handled properly, but it is also
necessary to ensure that higher level tombstones always cover counters.
parse_time() adds hourse, minutes, etc to a final value 'result'.
However, it is of type std::chrono::nanoseconds which means it is not
zeroed at initialization unless it is explicitly asked to do so.
Fixed debug mode failures in types_tyes and cql_query_test.
Message-Id: <20170125155239.1253-1-pdziepak@scylladb.com>
The integer_type_impl::parse_int() function uses boost::lexical_cast()
under the hood, which parses 8-bit numbers as characters. Fix the
function to lexical cast to 64-bit integer and convert the result to
integer_type_impl template type.
timeuuid_type_impl::compare_bytes is a "trichotomic" comparator (-1,
0, 1) while less() is a "less" comparator (false, true). The code
incorrectly returns c1 instead of c1 < 0 which breaks the ordering.
Fixes#1196.
Message-Id: <1473956716-5209-1-git-send-email-tgrabiec@scylladb.com>
There are several places in types.cc where we assume that sstring_view
range is null terminated. That may be not true and we should always use
either begin()/end() or data()/size() pairs.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
Checking bloom filters of sstables to compute max purgeable timestamp
for compaction is expensive in terms of CPU time. We can avoid
calculating it if we're not about to GC any tombstone.
This patch changes compacting functions to accept a function instead
of ready value for max_purgeable.
I verified that bloom filter operations no longer appear on flame
graphs during compaction-heavy workload (without tombstones).
Refs #1322.
If someone tried to naively use utf8_type->decompose("18wX"), this would
mysteriously fail, returning an empty key.
decompose takes a data_value, so the compiler looked for an implict
conversion from the string constant (const char*) to data_value. We did
not have such a conversion, only conversion from sstring. But the compiler
chose (backed by the C++ standard, no doubt) to implicitly convert the
const char* to a bool (!), and then use data_value(bool). It did not
convert the const char* to an sstring, nor did it warn about the possible
ambiguity.
So this patch adds a data_value(const char*) constructor, so people will
not fall into the same trap that I fell into...
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <1467643462-6349-1-git-send-email-nyh@scylladb.com>
This patch ensures type_parser can handle user defined types. It also
prefixes user_type_impl::make_name() with
org.apache.cassandra.db.marshal.UserType.
Fixes#631
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch adds a function to abstract_type that locates the usage of
a given user_type and recursively returns an updated version of the
containing type containing the updated user type.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch adds a virtual function to the abstract_type hierarchy to
tell whether a given type references the specified type. Needed to
implement the drop and alter type statements.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
A new user type is checked for compatibility against the previous
version of that type, so as to ensure that an updated field type
is compatible with the previous field type (e.g., altering a field
type from text to blob is allowed, but not the other way around).
However, it is also possible to add new fields to a user type. So,
when comparing a user type against its previous version, we should
also allow the current, new type to be longer than the previous one.
The current code instead allows for the previous type to be longer,
which this patch fixes.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
All the callers of do_serialize_mutation_form pass a valid tombstone
that is converted into a non-empty optional. This happens even if the
tombstone is empty (tombstone::timestamp == api::missing_timestamp).
This patch fixes this by passing in a reference to the tombstone which
is convertible to bool, based on whether it is empty or not.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <1460620528-3628-1-git-send-email-duarte@scylladb.com>
This reverts commit dadd097f9c.
That commit caused serialized forms of varint and decimal to have some
excess leading zeros. They didn't affect deserialization in any way but
caused computed tokens to differ from the Cassandra ones.
Fixes#898.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
Message-Id: <1455537278-20106-1-git-send-email-pdziepak@scylladb.com>
compatible: can be cast, keeps sort order
value-compatible: can be cast, may change sort order
frozen: values participate in sort order
unfrozen: only sort keys participate in sort order
Fixes#740.
