before this change, we rely on the default-generated fmt::formatter
created from operator<<, but fmt v10 dropped the default-generated
formatter.
in this change, we define formatters for `schema_mutations`,
and drop its operator<< .
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#17815
before this change, we rely on the default-generated fmt::formatter
created from operator<<, but fmt v10 dropped the default-generated
formatter.
in this change, we define formatters for mutation. but its operator<<
is preserved, as we are still using our homebrew generic formatter
for printing `std::vector<mutation>`, and this formatter is using
operator<< for printing the elements in vector.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Schema digest is calculated by querying for mutations of all schema
tables, then compacting them so that all tombstones in them are
dropped. However, even if the mutation becomes empty after compaction,
we still feed its partition key. If the same mutations were compacted
prior to the query, because the tombstones expire, we won't get any
mutation at all and won't feed the partition key. So schema digest
will change once an empty partition of some schema table is compacted
away.
Tombstones expire 7 days after schema change which introduces them. If
one of the nodes is restarted after that, it will compute a different
table schema digest on boot. This may cause performance problems. When
sending a request from coordinator to replica, the replica needs
schema_ptr of exact schema version request by the coordinator. If it
doesn't know that version, it will request it from the coordinator and
perform a full schema merge. This adds latency to every such request.
Schema versions which are not referenced are currently kept in cache
for only 1 second, so if request flow has low-enough rate, this
situation results in perpetual schema pulls.
After ae8d2a550d, it is more liekly to
run into this situation, because table creation generates tombstones
for all schema tables relevant to the table, even the ones which
will be otherwise empty for the new table (e.g. computed_columns).
This change inroduces a cluster feature which when enabled will change
digest calculation to be insensitive to expiry by ignoring empty
partitions in digest calculation. When the feature is enabled,
schema_ptrs are reloaded so that the window of discrepancy during
transition is short and no rolling restart is required.
A similar problem was fixed for per-node digest calculation in
18f484cc753d17d1e3658bcb5c73ed8f319d32e8. Per-table digest calculation
was not fixed at that time because we didn't persist enabled features
and they were not enabled early-enough on boot for us to depend on
them in digest calculation. Now they are enabled before non-system
tables are loaded so digest calculation can rely on cluster features.
Fixes#4485.
in C++20, compiler generate operator!=() if the corresponding
operator==() is already defined, the language now understands
that the comparison is symmetric in the new standard.
fortunately, our operator!=() is always equivalent to
`! operator==()`, this matches the behavior of the default
generated operator!=(). so, in this change, all `operator!=`
are removed.
in addition to the defaulted operator!=, C++20 also brings to us
the defaulted operator==() -- it is able to generated the
operator==() if the member-wise lexicographical comparison.
under some circumstances, this is exactly what we need. so,
in this change, if the operator==() is also implemented as
a lexicographical comparison of all memeber variables of the
class/struct in question, it is implemented using the default
generated one by removing its body and mark the function as
`default`. moreover, if the class happen to have other comparison
operators which are implemented using lexicographical comparison,
the default generated `operator<=>` is used in place of
the defaulted `operator==`.
sometimes, we fail to mark the operator== with the `const`
specifier, in this change, to fulfil the need of C++ standard,
and to be more correct, the `const` specifier is added.
also, to generate the defaulted operator==, the operand should
be `const class_name&`, but it is not always the case, in the
class of `version`, we use `version` as the parameter type, to
fulfill the need of the C++ standard, the parameter type is
changed to `const version&` instead. this does not change
the semantic of the comparison operator. and is a more idiomatic
way to pass non-trivial struct as function parameters.
please note, because in C++20, both operator= and operator<=> are
symmetric, some of the operators in `multiprecision` are removed.
they are the symmetric form of the another variant. if they were
not removed, compiler would, for instance, find ambiguous
overloaded operator '=='.
this change is a cleanup to modernize the code base with C++20
features.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#13687
Move mutation-related files to a new mutation/ directory. The names
are kept in the global namespace to reduce churn; the names are
unambiguous in any case.
mutation_reader remains in the readers/ module.
mutation_partition_v2.cc was missing from CMakeLists.txt; it's added in this
patch.
This is a step forward towards librarization or modularization of the
source base.
Closes#12788
Define table_schema_version as a distinct tagged_uuid class,
So it can be differentiated from other uuid-class types,
in particular table_id.
Added reversed(table_schema_version) for convenience
and uniformity since the same logic is currently open coded
in several places.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
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
There are two results of this patch:
1. New partitioner name column is persited on node's disk in scylla_tables
2. New partitioner name column is included into schema digest
This is achieved by including this new column in scylla tables mutation.
For that we:
1. Add partitioner name to the result of make_scylla_tables_mutation.
If table does not have a specific partitioner set and uses default
partitioner then we don't include the name of such default partitioner.
Only the name of custom partitioner is added if a table has one.
2. In create_table_from_mutations we check whether scylla tables mutation
has a partitioner name set. If so then we use it as a parameter for
schema_builder.
Note that previous patches have ensured that this new column will be included
into schema digest only after the whole cluster supports per table partitioners.
Before that, during rolling upgrade, new partitioner name column is hidden and
not shared with other nodes.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Schema digest is calculated by querying for mutations of all schema
tables, then compacting them so that all tombstones in them are
dropped. However, even if the mutation becomes empty after compaction,
we still feed its partition key. If the same mutations were compacted
prior to the query, because the tombstones expire, we won't get any
mutation at all and won't feed the partition key. So schema digest
will change once an empty partition of some schema table is compacted
away.
That's not a problem during normal cluster operation because the
tombstones will expire at all nodes at the same time, and schema
digest, although changes, will change to the same value on all nodes
at about the same time.
This fix changes digest calculation to not feed any digest for
partitions which are empty after compaction.
The digest returned by schema_mutations::digest() is left unchanged by
this patch. It affects the table schema version calculation. It's not
changed because the version is calculated on boot, where we don't yet
know all the cluster features. It's possible to fix this but it's more
complicated, so this patch defers that.
Refs #4485.
Asd
Now that the various get methods return nullptr or std::nullopt on
missing values, we don't need to do double lookups.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
cryptopp's config.h has the following pragma:
#pragma GCC diagnostic ignored "-Wunused-function"
It is not wrapped in a push/pop. Because of that, including cryptopp
headers disables that warning on scylla code too.
The issue has been reported as
https://github.com/weidai11/cryptopp/issues/793
To work around it, this patch uses a pimpl to have a single .cc file
that has to include cryptopp headers.
While at it, it also reduces the differences and code duplication
between the md5 and sha1 hashers.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
Replace stdx::optional and stdx::string_view with the C++ std
counterparts.
Some instances of boost::variant were also replaced with std::variant,
namely those that called seastar::visit.
Scylla now requires GCC 8 to compile.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20190108111141.5369-1-duarte@scylladb.com>
In the previous patch, we added a "view virtual" flag on columns. In this
patch we add persistance to this flag: I.e., writing it to the on-disk
schema table and reading it back on startup. But the implementation is
not as simple as adding a flag:
In the on-disk system tables, we have a "columns" table listing all the
columns in the database and their types. Cqlsh's "DESCRIBE MATERIALIZED
VIEW" works by reading this "columns" table, and listing all of the
requested view's columns. Therefore, we cannot add "virtual columns" -
which are columns not added by the user and not intended to be seen -
to this list.
We therefore need to create in this patch a separate list for virtual
columns, in a new table "view_virtual_columns". This table is essentially
identical to the existing "columns" table, just separate. We need to write
each column to the appropriate table (columns with the view_virtual flag to
"view_virtual_columns", columns without it to the old "columns"), read
from both on startup, and remember to delete columns from both when a table
is dropped.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Digest only looks like live values, ignoring deletion
information. Equality should be consistent with that, so that schemas
considered equal do not trigger the alter path unnecessarily.
When migrating schema tables from v2 to v3, mutations underlying
table schema will change, and so will their digest. However, we want
the digest to be the same on new nodes as on the old nodes, because
schema exchange is not possible between the two nodes, so they
must to request schema definitions from each other.
The solution is to make the digest persistable, so that it sticks to
given table schema, surviving both migration and node restarts. On
migration from v2, the digest will be calculated from v2 mutations, so
it will be the same on new and old nodes.
It will be used to store Scylla spcific table metadata. We cannot
store it in the standard "tables" table for compatibility reasons -
Cassandra will fail to read schema if it encounteres columns it is not
expecting.
This patch allows a view schema to be frozen. To unfreeze such a
schema, we add an is_view attribute to the schema idl.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
We want the node's schema version to change whenever
table_schema_version of any table changes. The latter is calculated by
hashing mutations so we should also use mutation hash when calculating
schema digest.
We must use canonical_mutation form to allow for changes in the schema
of schema tables. The node which deserializes schema mutations may not
have the same version of the schema tables so we cannot use
frozen_mutation, which is a schema dependent form.
