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>
Propagate acquired semaphore units to mutate_MV() to allow the
semaphore to be incrementally signalled as view updates are processed
by view replicas.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Working in terms of frozen_mutations allows us to account more
precisely the memory pending view updates consume at the storage_proxy
layer.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
When a view's partition key contains only columns from the base's partition
key (and not an additional one), the liveness (existance or disappearance)
of a view-table row is tied to the liveness of the base table row - and
that depends not only on selected columns (base-table columns SELECTed to
also appear in the view) but also on unselected columns.
This means that we may need to keep a view row alive even without data,
just because some unselected column is alive in the base table. Before this
patch we tried to build a single "row marker" in the view column which
summarizes the liveness information in all unselected columns, but this
proved unworkable, as explained in issue #3362 and as will be demonstrated
in unit tests in a later patch.
Because we can't replace several unselected cells by one row marker, what
we do in this patch is to add for each for the unselected cell a "virtual
cell" which contains the cell's liveness information (timestamp, deletion,
ttl) but not its value. For collections, we can't represent the entire
collection by one virtual cell, and rather need a collection of virtual
cells.
This patch just adds the virtual columns to the view schema. Code in
the previous patch, when it notices the virtual columns in the view's
schema, added the appropriate content into these columns.
We may need to add virtual columns to a view when first created, but also
when an unselected column is added to the base table with "ALTER TABLE",
so both are supported in this patch.
Fixes#3362.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This commit adapts view_stats structure so it can be passed
to storage_proxy as write stats. Thanks to that, mv replica updates
will not interfere with user write metrics. As a side effect it also
provides more stats to replica view updates.
Closes#3385Closes#3416
This commit introduces view statistics:
- updates pushed to local/remote replicas
- updates failed to be pushed to local/remote replicas
Metrics are kept on per-table basis, i.e. updates_pushed_remote
shows the number of total updates (mutations) pushed to all paired
mv replicas that this particular table has.
Every single update is taken into consideration, so if view update
requires removing a row from one view and adding a row to another,
it will be counted as 2 updates.
References #3385
References #3416
While we now send view mutations asynchronously in the normal view
write path, other processes interested in sending view updates, such
as streaming or view building, may wish to do it synchronously.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
When generating updates for a materialized view we need to read the
existing base row, to be able to determine the primary key of the view
row the new base update will supplant, in case the view includes a
base non-primary key column in its own primary key. That old view row
will be tombstoned or updated, if it exists, depending on the difference
between the new base row and the existing one, if any.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Introduce the calculate_affected_clustering_ranges() function to
calculate the smallest subject of affected clustering ranges that we
need to query for.
The update_requires_read_before_write() function checks whether
a view is potentially affected by the base update.
The patch also cleans up the may_be_affected_by() function.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
The write path uses a base schema at a particular version, and we
want it to use the materialized views at the corresponding version.
To achieve this, we need to map the state currently in db::view::view
to a particular schema version, which this patch does by introducing
the view_info class to hold the state previously in db::view::view,
and by having a view schema directly point to it.
The changes in the patch are thus:
1) Introduce view_info to hold the extra view state;
2) Point to the view_info from the schema;
3) Make the functions in the now stateless db::view::view non-member;
4) Remove the db::view::view class.
All changes are structural and don't affect current behavior.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This adds a function mutate_MV() which takes view mutations and sends
them to the appropriate nodes (this may be the current node, or a
remote node).
This is only a partial implementation - we still don't do the local
batch log (to survive reboots and failures) and some other stuff which
is left commented out.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch adds the view_update_builder class, which is responsible
for calculating the mutations to apply to a column family's
materialized views, given a streamed_mutation representing an update
to the base table and a streamed_mutation representing the
pre-existing rows which the update covers.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
To help calculate the view mutations from a base update, we store in
the view class the column that's part of the view's primary key but
not part of the base's, if such column exists.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch adds the matches_view_filter() function which specifies
whether a given base row matches the view filter. Unlike
may_be_affected_by(), this function has no false positives.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch adds the may_be_affected_by() function to the view class,
which is responsible to determine whether an update to a base class
affects one of its views.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch adds the view class, which will contains functions related
to populating a view, either from the base table's write path or from
the view building mechanism which copies over already existing data in
the base table.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
