Commit Graph

1061 Commits

Author SHA1 Message Date
Avi Kivity
bc75e2c1d1 treewide: wrap runtime formats with fmt::runtime for fmt 8
fmt 8 checks format strings at compile time, and requires that
non-compile-time format strings be wrapped with fmt::runtime().

Do that, and to allow coexistence with fmt 7, supply our own
do-nothing version of fmt::runtime() if needed. Strictly speaking
we shouldn't be introducing names into the fmt namespace, but this
is transitional only.

Closes #9640
2021-11-17 15:21:36 +02:00
Avi Kivity
720e9521f0 utils: build_id: correct fmt include
fmt::print(std::ostream&) is in <fmt/ostream.h>

Closes #9641
2021-11-17 09:02:57 +02:00
Tomasz Grabiec
bf6898a5a0 lsa: Add sanity checks around lsa_buffer operations
We've been observing hard to explain crashes recently around
lsa_buffer destruction, where the containing segment is absent in
_segment_descs which causes log_heap::adjust_up to abort. Add more
checks to catch certain impossible senarios which can lead to this
sooner.

Refs #9192.
Message-Id: <20211116122346.814437-1-tgrabiec@scylladb.com>
2021-11-16 14:25:02 +02:00
Tomasz Grabiec
4d627affc3 lsa: Mark compact_segment_locked() as noexcept
We cannot recover from a failure in this method. The implementation
makes sure it never happens. Invariants will be broken if this
throws. Detect violations early by marking as noexcept.

We could make it exception safe and try to leave the data structures
in a consistent state but the reclaimer cannot make progress if this throws, so
it's pointless.

Refs #9192
Message-Id: <20211116122019.813418-1-tgrabiec@scylladb.com>
2021-11-16 14:23:10 +02:00
Pavel Emelyanov
4a70e0aa57 system_keyspace: Table with config options
A config option value is reported as 'text' type and contains
a string as it would looks like in json config.

The table is UPDATE-able. Only the 'value' columnt can be set
and the value accepted must be string. It will be converted into
the option type automatically, however in current implementation
is't not 100% precise -- conversion is lexicographical cast which
only works for simple types. However, liveupdate-able values are
only of those types, so it works in supported cases.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
2021-11-11 16:39:34 +03:00
Pavel Emelyanov
b3fee616ea utils: Add config_src::source_name() method
To get a human-readable string from abstract source type.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
2021-11-11 15:15:05 +03:00
Pavel Emelyanov
d513034ca4 utils: Ability to set_value(sstring) for an option
There soon will appear an updateable system.config table that
will push sstrings into names_value-s. Prepare for this change
by adding the respective .set_value() call. Since the update
only works for LiveUpdate-able options, and inability to do it
can be propagated back to the caller make this method return
true/false whether the update took place or not.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
2021-11-11 15:15:05 +03:00
Pavel Emelyanov
c226c0a149 utils: Internal change of config option
When a named_value is .set_value()-d the caller may specify the reason
for this change. If not specified it's set to None, but None means
"it was there by default and was't changed" so it's a bit of a lie.

Add an explicit Internal reason. It's actually used by the directories
thing that update all directories according to --workdir option.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
2021-11-11 15:15:05 +03:00
Pavel Emelyanov
2959ebf393 utils: Mark some config_file methods noexcept
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
2021-11-11 15:15:05 +03:00
Pavel Emelyanov
b3a4f9e194 utils: Introduce || operator for named_values
Those named_values that support .empty() check can be "selected"
like this

    auto& v = option_a() || option_b() || option_c();

This code will put into v a reference to the first non-empty
named_value out of a/b/c.

This "selection" is actually used on start when scylla decides
which config options to use as listen/broadcact/rpc/etc. addresses.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
2021-11-08 17:33:27 +03:00
Tomasz Grabiec
31bc1eb681 Merge 'Memtable reversing reader: fix computing rt slice, if there was previously emitted range tombstone.' from Michał Radwański
This PR started by realizing that in the memtable reversing reader, it
never happened on tests that `do_refresh_state` was called with
`last_row` and `last_rts` which are not `std::nullopt`.

Changes
- fix memtable test (`tesst_memtable_with_many_versions_conforms_to_mutation_source`), so that there is a background job forcing state refreshes,
- fix the way rt_slice is computed (was `(last_rts, cr_range_snapshot.end]`, now is `[cr_range_snapshot.start, last_rts)`).

Fixes #9486

Closes #9572

* github.com:scylladb/scylla:
  partition_snapshot_reader: fix indentation in fill_buffer
  range_tombstone_list: {lower,upper,}slice share comparator implementation
  test: memtable: add full_compaction in background
  partition_snapshot_reader: fix obtaining rt_slice, if Reversing and _last_rts was set
  range_tombstone_list: add lower_slice
2021-11-05 15:27:03 +01:00
Nadav Har'El
5e52858295 rjson, alternator: rename set() functions add()
The rjson::set() *sounds* like it can set any member of a JSON object
(i.e., map), but that's not true :-( It calls the RapidJson function
AddMember() so it can only add a member to an object which doesn't have
a member with the same name (i.e., key). If it is called with a key
that already has a value, the result may have two values for the same
key, which is ill-formed and can cause bugs like issue #9542.

So in this patch we begin by renaming rjson::set() and its variant to
rjson::add() - to suggest to its user that this function only adds
members, without checking if they already exist.

After this rename, I was left with dozens of calls to the set() functions
that need to changed to either add() - if we're sure that the object
cannot already have a member with the same name - or to replace() if
it might.

The vast majority of the set() calls were starting with an empty item
and adding members with fixed (string constant) names, so these can
be trivially changed to add().

It turns out that *all* other set() calls - except the one fixed in
issue #9542 - can also use add() because there are various "excuses"
why we know the member names will be unique. A typical example is
a map with column-name keys, where we know that the column names
are unique. I added comments in front of such non-obvious uses of
add() which are safe.

Almost all uses of rjson except a handful are in Alternator, so I
verified that all Alternator test cases continue to pass after this
patch.

Fixes #9583
Refs #9542

Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20211104152540.48900-1-nyh@scylladb.com>
2021-11-04 16:35:38 +01:00
Nadav Har'El
b95e431228 alternator: fix bug in ReturnValues=ALL_NEW
This patch fixes a bug in UpdateItem's ReturnValues=ALL_NEW, which in
some cases returned the OLD (pre-modification) value of some of the
attributes, instead of its NEW value.

The bug was caused by a confusion in our JSON utility function,
rjson::set(), which sounds like it can set any member of a map, but in
fact may only be used to add a *new* member - if a member with the same
name (key) already existed, the result is undefined (two values for the
same key). In ReturnValues=ALL_NEW we did exactly this: we started with
a copy of the original item, and then used set() to override some of the
members. This is not allowed.

So in this patch, we introduce a new function, rjson::replace(), which
does what we previously thought that rjson::set() does - i.e., replace a
member if it exists, or if not, add it. We call this function in
the ReturnValues=ALL_NEW code.

This patch also adds a test case that reproduces the incorrect ALL_NEW
results - and gets fixed by this patch.

In an upcoming patch, we should rename the confusingly-named set()
functions and audit all their uses. But we don't do this in this patch
yet. We just add some comments to clarify what set() does - but don't
change it, and just add one new function for replace().

Fixes #9542

Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20211104134937.40797-1-nyh@scylladb.com>
2021-11-04 16:34:58 +01:00
Michał Radwański
07e78807e6 range_tombstone_list: add lower_slice
lower_slice returns the range tombstones which have end inside range
[start, before).
2021-11-02 10:50:31 +01:00
Nadav Har'El
666017f2f0 Merge 'Convert last uses of sprint() to fmt::format()' from Avi Kivity
sprint() uses the printf-style formatting language while most of our
code uses the Python-derived format language from fmt::format().

The last mass conversion of sprint() to fmt (in 1129134a4a)
missed some callers (principally those that were on multiple lines, and
so the automatic converter missed them). Convert the remainder to
fmt::format(), and some sprintf() and printf() calls, so we have just
one format language in the code base. Seastar::sprint() ought to be
deprecated and removed.

Test: unit (dev)

Closes #9529

* github.com:scylladb/scylla:
  utils: logalloc: convert debug printf to fmt::print()
  utils: convert fmt::fprintf() to fmt::print()
  main: convert fprint() to fmt::print()
  compress: convert fmt::sprintf() to fmt::format()
  tracing: replace seastar::sprint() with fmt::format()
  thrift: replace seastar::sprint() with fmt::format()
  test: replace seastar::sprint() with fmt::format()
  streaming: replace seastar::sprint() with fmt::format()
  storage_service: replace seastar::sprint() with fmt::format()
  repair: replace seastar::sprint() with fmt::format()
  redis: replace seastar::sprint() with fmt::format()
  locator: replace seastar::sprint() with fmt::format()
  db: replace seastar::sprint() with fmt::format()
  cql3: replace seastar::sprint() with fmt::format()
  cdc: replace seastar::sprint() with fmt::format()
  auth: replace seastar::sprint() with fmt::format()
2021-10-28 22:33:23 +03:00
Avi Kivity
c30be50252 utils: logalloc: convert debug printf to fmt::print()
Standardize on one format language.
2021-10-28 10:48:08 +03:00
Raphael S. Carvalho
affa1d9b04 utils/estimated_histogram.hh: fix division-by-zero in mean()
if mean() is called when there are no elements in the histogram,
a runtime error will happen due to division-by-zero.
approx_exponential_histogram::mean() handles it but for some
reason we forgot to do the same for estimated_histogram.

this problem was found when adding an unit test which calls
mean() in an empty histogram.

Fixes #9531.

Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20211027142813.56969-1-raphaelsc@scylladb.com>
2021-10-28 08:58:25 +03:00
Avi Kivity
379454c235 utils: convert fmt::fprintf() to fmt::print()
Standardizing on a common format language.
2021-10-27 17:02:00 +03:00
Benny Halevy
d96a67eb57 abstract_replication_strategy: use shared_ptr in registry
Enable creating shared_ptr<BaseClass> in nonstatic_class_registry
using BaseClass::ptr_type and use that for
abstract_replication_strategy.

While at it, also clean up compressor with that respect
to define compressor::ptr_type as shared_ptr<compressor>
thus simplifying compressor_registry.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2021-10-13 12:39:36 +03:00
Nadav Har'El
33f8ec09df Merge 'treewide: improve compatibility with gcc 11' from Avi Kivity
Our source base drifted away from gcc compatibility; this mostly
restores the ability to build with gcc. An important exception is
coroutines that have an initializer list [1]; this still doesn't work.

We aim to switch back to gcc 11 if/when this gives us better
C++ compatibility and performance.

Test: unit (dev)

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98056

Closes #9459

* github.com:scylladb/scylla:
  test: radix_tree_printer: avoid template specialization in class context
  test: raft: avoid ignored variable errors
  test: reader_concurrency_semaphore_test: isolate from namespace of source_location
  test: cql_query_test: drop unused lambda assert_replication_not_contains
  test: commitlog_test: don't use deprecated seastar::unaligned_cast
  test: adjust signed/unsigned comparisons in loops and boost tests
  build: silence some gcc 11 warnings
  sstables: processing_result_generator: make coroutine support palatable for C++20 compilers
  managed_bytes: avoid compile-time loop in converting constructor
  service: service_level_controller: drop unused variable sl_compare
  raft: disambiguate promise name in raft::active_read
  locator: azure_snitch: use full type name in definition of globals
  cql3: statements: create_service_level_statement: don't ignore replace_defaults()
  cql3: statement_restrictions: adjust call to std::vector deduction guide
  types: remove recursive constraint in deserialize_value
  cql3: restrictions: relax constraint on visitor_with_binary_operator_content
  treewide: handle switch statements that return
  cql3: expr: correct type of captured map value_type
  cdc: adjust type of streams_count
  alternator: disambiguate attrs_to_get in table_requests
2021-10-11 16:54:01 +03:00
Pavel Emelyanov
581382edad distributed_loader, utils: Move verify_owner_and_mode
This method sits in dist.loader, but really belongs to util/ as it
just works on an "abstract" path and doesn't need to know what this
path is about. Another sign of layering violation is the inclusion
of dist.loader code into util/ stuf.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
2021-10-11 11:03:51 +03:00
Avi Kivity
c38f18163e managed_bytes: avoid compile-time loop in converting constructor
managed_bytes_basic_view is a template with a constructor that
converts from one instantiation of the template to another.
Unfortunately when gcc encounters the associated constraint, it
instantiates the template which forces it to evaluate the constraint
again, sending it into a loop.

Fix that by making the converting constructor a template itself,
delaying instantiation. The constraint is strengthened so the set
of types on which the constructor works is unchanged.
2021-10-10 18:16:50 +03:00
Avi Kivity
d3f8148807 utils: untie rjson.hh from base64.hh
base64.hh pulls in the huge rjson.hh, so if someone just wants
a base64 codec they have to pull in the entire rapidjson library.

Move the json related parts of base64.hh to rjson.hh and adjust
includes and namespaces.

In practice it doesn't make much difference, as all users of base64
appear to want json too. But it's cleaner not to mix the two.

Closes #9433
2021-10-05 12:57:54 +02:00
Avi Kivity
369afe3124 treewide: use coroutine::maybe_yield() instead of co_await make_ready_future()
The dedicated API shows the intent, and may be a tiny bit faster.

Closes #9382
2021-09-23 12:28:56 +02:00
Avi Kivity
15819e0304 Merge "Database start/stop code sanitation" from Pavel E
"
Currently database start and stop code is quite disperse and
exists in two slightly different forms -- one in main and the
other one in cql_test_env. This set unifies both and makes
them look almost the perfect way:

    sharded<database> db;
    db.start(<dependencies>);
    auto stop = defer([&db] { db.stop().get(); });
    db.invoke_on_all(&database::start).get();

with all (well, most) other mentionings of the "db" variable
being arguments for other services' dependencies.

tests: unit(dev, release), unit.cross_shard_barrier(debug)
       dtest.simple_boot_shutdown(dev)
refs: #2737
refs: #2795
refs: #5489

"

* 'br-database-teardown-unification-2' of https://github.com/xemul/scylla: (26 commits)
  main: Log when database starts
  view_update_generator: Register staging sstables in constructor
  database, messaging: Delete old connection drop notification
  database, proxy: Relocate connection-drop activity
  messaging, proxy: Notify connection drops with boost signal
  database, tests: Rework recommended format setting
  database, sstables_manager: Sow some noexcepts
  database: Eliminate unused helpers
  database: Merge the stop_database() into database::stop()
  database: Flatten stop_database()
  database: Equip with cross-shard-barrier
  database: Move starting bits into start()
  database: Add .start() method
  main: Initialize directories before database
  main, api: Detach set_server_config from database and move up
  main: Shorten commitlog creation
  database: Extract commitlog initialization from init_system_keyspace
  repair: Shutdown without database help
  main: Shift iosched verification upward
  database: Remove unused mm arg from init_non_system_keyspaces()
  ...
2021-09-20 10:26:13 +03:00
Pavel Emelyanov
e324230648 utils: Introduce cross-shard barrier (with test)
Add a synchronization facility to let shards wait for each
other to pass through certain points in the code.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
2021-09-15 17:35:12 +03:00
Avi Kivity
daf028210b build: enable -Winconsistent-missing-override warning
This warning can catch a virtual function that thinks it
overrides another, but doesn't, because the two functions
have different signatures. This isn't very likely since most
of our virtual functions override pure virtuals, but it's
still worth having.

Enable the warning and fix numerous violations.

Closes #9347
2021-09-15 12:55:54 +03:00
Michał Radwański
7c8b895285 utils/small_vector: remove noexcept from the copy constructor, which potentially throws
The copy constructor of small vector has a noexcept specifier, however
it calls `reserve(size_t)`, which can throw `std::bad_alloc`. This
causes issues when using it inside tests that use
alloc_failure_injector, but potentially could also float up in the
production.

Closes #9338
2021-09-15 12:55:54 +03:00
Botond Dénes
65913f4cfa utils: UUID_gen: introduce negate() 2021-09-09 11:49:05 +03:00
Pavel Emelyanov
e6d568b38e btree: Add commens in .clone() and .clear()
There are two tricky places about corner leaves pointers
managements. Add comments describing the magic.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
2021-08-31 12:36:54 +03:00
Pavel Emelyanov
d1a1a2dac2 btree: Dont leak kids on clone roll-back
When failed-to-be-cloned node cleans itself it must also clear
all its child nodes. Plain destroy() doesn't do it, it only
frees the provided node.

fixes: #9248

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
2021-08-31 12:23:49 +03:00
Pavel Emelyanov
1d857d604a btree: Destroy, not drop, node on clone roll-back
The node in this place is not yet attached to its parent, so
in btree::debug::yes (tests only) mode the node::drop()'s parent
checks will access null parent pointer.

However, in non-tesing runtime there's a chance that a linear
node fails to clone one of its keys and gets here. In this case
it will carry both leftmost and rightmost flags and the assertion
in drop will fire.

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
2021-08-31 12:23:49 +03:00
Michał Chojnowski
126baa7850 utils: compact-radix-tree: fix accidental cache line bouncing
Whenever a node_head_ptr is assigned to nil_root, the _backref inside it is
overwritten. But since nil_root is shared between shards, this causes severe
cache line bouncing. (It was observed to reduce the total write throughput
of Scylla by 90% on a large NUMA machine).

This backreference is never read anyway, so fix this bug by not writing it.

Fixes #9252

Closes #9246
2021-08-26 17:22:22 +03:00
Nadav Har'El
d598a94b43 Merge: everywhere: mark deferred actions noexcept
Merged patch series by By Benny Halevy:

Prepare for updating seastar submodule to a change
that requires deferred actions to be noexcept
(and return void).

Test: unit(dev, debug)

* tag 'deferred_action-noexcept-v1' of github.com:bhalevy/scylla:
  everywhere: make deferred actions noexcept
  cql3: prepare_context: mark methods noexcept
  commitlog: segment, segment_manager: mark methods noexcept
  everywhere: cleanup defer.hh includes
2021-08-23 11:16:17 +03:00
Benny Halevy
4439e5c132 everywhere: cleanup defer.hh includes
Get rid of unused includes of seastar/util/{defer,closeable}.hh
and add a few that are missing from source files.

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
2021-08-22 21:11:39 +03:00
Vlad Zolotarov
7bd1bcd779 loading_shared_values/loading_cache: get rid of iterators interface and return value_ptr from find(...) instead
loading_shared_values/loading_cache'es iterators interface is dangerous/fragile because
iterator doesn't "lock" the entry it points to and if there is a
preemption point between aquiring non-end() iterator and its
dereferencing the corresponding cache entry may had already got evicted (for
whatever reason, e.g. cache size constraints or expiration) and then
dereferencing may end up in a use-after-free and we don't have any
protection against it in the value_extractor_fn today.

And this is in addition to #8920.

So, instead of trying to fix the iterator interface this patch kills two
birds in a single shot: we are ditching the iterators interface
completely and return value_ptr from find(...) instead - the same one we
are returning from loading_cache::get_ptr(...) asyncronous APIs.

A similar rework is done to a loading_shared_values loading_cache is
based on: we drop iterators interface and return
loading_shared_values::entry_ptr from find(...) instead.

loading_cache::value_ptr already takes care of "lock"ing the returned value so that it
would relain readable even if it's evicted from the cache by the time
one tries to read it. And of course it also takes care of updating the
last read time stamp and moving the corresponding item to the top of the
MRU list.

Fixes #8920

Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
Message-Id: <20210817222404.3097708-1-vladz@scylladb.com>
2021-08-22 16:49:40 +03:00
Piotr Dulikowski
5a0942a0f8 utils,alternator: move base64 code from alternator to utils
The base64 encoding/decoding functions will be used for serialization of
hint sync point descriptions. Base64 format is not specific to
Alternator, so it can be moved to utils.
2021-08-09 09:24:36 +02:00
Michael Livshin
0eb2eb1b44 rename coarse_clock to coarse_steady_clock
Also add a comment to explain why it exists.

Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>

Closes #9123
2021-08-02 17:41:21 +03:00
Michael Livshin
71d721a97e logalloc: add on-stall memory reclaim diagnostics
Reuse the existing `reclaim_timer` for stall detection.

* Since a timer is now set around every reclaim and compaction, use a
  coarse one for speed.
* Set log level according to conditions (stalls deserve a warning).
* Add compaction/migration/eviction/allocation stats.

Refs #4186.

Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>
2021-08-01 21:51:08 +03:00
Michael Livshin
68ab3948f8 utils: add a coarse clock
Implement a millisecond-resolution `std::chrono`-style clock using
`CLOCK_MONOTONIC_COARSE`.  The use cases are those where you care
about clock sampling latency more than about accuracy.

Assuming non-ancient versions of the kernel & libc, all clock types
recognized by `clock_gettime()` are implemented through a vDSO, so
`clock_gettime()` is not an actual system call.  That means that even
`CLOCK_MONOTONIC` (which is what `std::chrono::steady_clock` uses) is
not terribly expensive in practice.

But `CLOCK_MONOTONIC_COARSE` is still 3.5 times faster than that (on
my machine the latencies are 4ns versus 14ns) and is also supposed to
be easier on the cache.

The actual granularity of `CLOCK_MONOTONIC_COARSE` is tick (on x86-64,
anyway) -- but `getclock_getres()` says it has millisecond resolution,
so we use that.

Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>
2021-08-01 21:51:08 +03:00
Michael Livshin
20c760e638 logalloc: split tracker::impl::reclaim into reclaim & reclaim_locked
Similarly to compact_and_evict().

Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>
2021-08-01 19:34:13 +03:00
Michael Livshin
a96aed3973 logalloc: metrics: remove unneeded captures and a pleonasm
Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>
2021-08-01 19:34:13 +03:00
Michael Livshin
aa6c8ef582 logalloc: add metrics for evicted and freed memory
Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>
2021-08-01 19:34:13 +03:00
Michael Livshin
a6283b322b logalloc: count evicted memory
Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>
2021-08-01 19:34:13 +03:00
Michael Livshin
4bcd91a09a logalloc: count freed memory
(On the individual free() request level, i.e. similarly to allocs)

Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>
2021-08-01 19:34:13 +03:00
Piotr Sarna
60072045db Merge 'cql3: replace cql3::selection::selectable::raw ...
hierarchy with expressions' from Avi Kivity

Currently, the grammar has two parallel hierarchies. One hierarchy is
used in the WHERE clause, and is based on a combination of `term`
and expressions. The other is used in the SELECT clause, and is
using the cql3::selection::selectable hierarchy. There is some overlap
between the hierarchies: both can name columns. Logically, however,
they overlap completely - in SQL anything you can select you can
filter on, and vice versa. So merging the two hierarchies is important if
we want to enrich CQL. This series does that, partially (see below),
converting the SELECT clause to expressions.

There is another hierarchy split: between the "raw", pre-prepare object
hierarchy, and post-prepare non-raw. This series limits itself to converting
the raw hierarchy and leaves the non-raw hierarchy alone.

An important design choice is not to have this raw/non-raw split in expressions.
Note that most of the hierarchy is completely parallel: addition is addition
both before prepare and after prepare (but see [1]). The main difference
is around identifiers - before preparation they are unresolved, and after
preparation they become `column_definition` objects. We resolve that by
having two separate types: `unresolved_identifier` for the pre-prepare phase,
and the existing `column_value` for post-prepare phase.

Alternative choices would be to keep a separate expression::raw variant, or
to template the expression variant on whether it is raw or not. I think it would
cause undue bloat and confusion.

Note the series introduces many on_internal_error() calls. This is because
there is not a lot of overlap in the hierarchies today; you can't have a cast in
the WHERE clause, for example. These on_internal_error() calls cannot be
triggered since the grammar does not yet allow such expressions to be
expressed. As we expand the grammar, they will have to be replaced with
working implementations.

Lastly, field selection is expressible in both hierarchies. This series does not yet
merge the two representations (`column_value.sub` vs `field_selection`), but it
should be easy to do so later.

[1] the `+` operator can also be translated to list concatenation, which we may
  choose to represent by yet another type.

Test: unit(dev)

Closes #9087

* github.com:scylladb/scylla:
  cql3: expression: update find_atom, count_if for function_call, cast, field_selection
  cql3: expressions: fix printing of nested expressions
  cql3: selection: replace selectable::raw with expression
  cql3: expression: convert selectable::with_field_selection::raw to expression
  cql3: expression: convert selectable::with_cast::raw to expression
  cql3: expression: convert selectable::with_anonymous_function::raw to expression
  cql3: expression: convert selectable::with_function_call::raw to expressions
  cql3: selectable: make selectable::raw forward-declarable
  cql3: expressions: convert writetime_or_ttl::raw to expression
  cql3: expression: add convenience constructor from expression element to nested expression
  utils: introduce variant_element.hh
  cql3: expression: use nested_expression in binary_operator
  cql3: expression: introduce nested_expression class
  Convert column_identifier_raw's use as selectable to expressions
  make column_identifier::raw forward declarable
  cql3: introduce selectable::with_expression::raw
2021-07-30 09:57:39 +02:00
Avi Kivity
14fd886c72 utils: int_range: change to std::strong_ordering
Ref #1449.
2021-07-28 13:29:50 +03:00
Avi Kivity
89bd7737f3 utils: big_decimal: change to std::strong_ordering
Ref #1449.
2021-07-28 13:28:21 +03:00
Avi Kivity
59941c536c utils: fragment_range: change to std::strong_ordering
Ref #1449.
2021-07-28 13:27:49 +03:00
Avi Kivity
7729ff03ad uuid: change comparators to std::strong_ordering
Ref #1449.
2021-07-28 13:20:32 +03:00