Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
Move replica-oriented classes to the replica namespace. The main
classes moved are ::database, ::keyspace, and ::table, but a few
ancillary classes are also moved. There are certainly classes that
should be moved but aren't (like distributed_loader) but we have
to start somewhere.
References are adjusted treewide. In many cases, it is obvious that
a call site should not access the replica (but the data_dictionary
instead), but that is left for separate work.
scylla-gdb.py is adjusted to look for both the new and old names.
The database, keyspace, and table classes represent the replica-only
part of the objects after which they are named. Reading from a table
doesn't give you the full data, just the replica's view, and it is not
consistent since reconciliation is applied on the coordinator.
As a first step in acknowledging this, move the related files to
a replica/ subdirectory.
First, it's to fix the discarded future during the register. The
future is not actually such, as it's always the no-op ready one as
at that stage the view_update_generator is neither aborted nor is
in throttling state.
Second, this change is to keep database start-up code in main
shorter and cleaner. Registering staging sstables belongs to the
view_update_generator start code.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Every time db/config.hh is modified (e.g., to add a new configuration
option), 110 source files need to be recompiled. Many of those 110 didn't
really care about configuration options, and just got the dependency
accidentally by including some other header file.
In this patch, I remove the include of "db/config.hh" from all header
files. It is only needed in source files - and header files only
need forward declarations. In some cases, source files were missing
certain includes which they got incidentally from db/config.hh, so I
had to add these includes explicitly.
After this patch, the number of source files that get recompiled after a
change to db/config.hh goes down from 110 to 45.
It also means that 65 source files now compile faster because they don't
include db/config.hh and whatever it included.
Additionally, this patch also eliminates a few unnecessary inclusions
of database.hh in other header files, which can use a forward declaration
or database_fwd.hh. Some of the source files including one of those
header files relied on one of the many header files brought in by
database.hh, so we need to include those explicitly.
In view_update_generator.hh something interesting happened - it *needs*
database.hh because of code in the header file, but only included
database_fwd.hh, and the only reason this worked was that the files
including view_update_generator.hh already happened to unnecessarily
include database.hh. So we fix that too.
Refs #1
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20210505102111.955470-1-nyh@scylladb.com>
There is no reason to read a single SSTable at a time from the staging
directory. Moving SSTables from staging directory essentially involves
scanning input SSTables and creating new SSTables (albeit in a different
directory).
We have a mechanism that does that: compactions. In a follow up patch, I
will introduce a new specialization of compaction that moves SSTables
from staging (potentially compacting them if there are plenty).
In preparation for that, some signatures have to be changed and the
view_updating_consumer has to be more compaction friendly. Meaning:
- Operating with an sstable vector
- taking a table reference, not a database
Because this code is a bit fragile and the reviewer set is fundamentally
different from anything compaction related, I am sending this separately
Signed-off-by: Glauber Costa <glauber@scylladb.com>
The view_update_generator acceps (and keeps) database and storage_proxy,
the latter is only needed to initialize the view_updating_consumer which,
in turn, only needs it to get database from (to find column family).
This can be relaxed by providing the database from _generator to _consumer
directly, without using the storage_proxy in between.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Message-Id: <20200207112427.18419-1-xemul@scylladb.com>
Hold the _sstable_deletion_sem while moving sstables from the staging directory
so not to move them under the feet of table::snapshot.
Fixes#5340
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
By default, semaphore exceptions bring along very little context:
either that a semaphore was broken or that it timed out.
In order to make debugging easier without introducing significant
runtime costs, a notion of named semaphore is added.
A named semaphore is simply a semaphore with statically defined
name, which is present in its errors, bringing valuable context.
A semaphore defined as:
auto sem = semaphore(0);
will present the following message when it breaks:
"Semaphore broken"
However, a named semaphore:
auto named_sem = named_semaphore(0, named_semaphore_exception_factory{"io_concurrency_sem"});
will present a message with at least some debugging context:
"Semaphore broken: io_concurrency_sem"
It's not much, but it would really help in pinpointing bugs
without having to inspect core dumps.
At the same time, it does not incur any costs for normal
semaphore operations (except for its creation), but instead
only uses more CPU in case an error is actually thrown,
which is considered rare and not to be on the hot path.
Refs #4999
Tests: unit(dev), manual: hardcoding a failure in view building code
