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>
mutation_fragments are going to be caching their size in memory. In
order to be able to invalidate that correctly, they need to know when
that size may change (but avoid invalidation when it is not necessary).
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>
A function to find the appropriate replica to send a view update to.
This patch creates a new source file db/view/view.cc. We should
eventually move a lot more of the materialized views code there.
Signed-off-by: Nadav Har'El <nyh@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>
This patch adds the view_updates::generate_update() function to
generate view updates given a base row update and the corresponding,
pre-existing row. This function will decide which of the previously
introduced functions to call based on whether there is a pre-existing
row and whether there exists a regular base column that's part of the
view's PK.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch adds a function to replace a view row given a base
table update and the pre-existing row, which simply deletes the old
view entry and adds a new one.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch introduces the view_updates::update_entry function,
which creates the updates to apply to the existing view entry given
the base table row before and after the update.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch introduces the view_updates::delete_old_entry function,
which creates a view row mutation to delete an entry given an updated
base table row.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch introduces the view_updates::create_entry function, which
creates a view row mutation given a new base table row.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch adds a function to compute the row marker of a view row
given the base row. There are two cases to consider when building the
row marker: 1) there is a column C that is a regular base column but
is in the view PK; and 2) the columns for the base and the view PKs
are the same.
For 1), the view row marker timestamp will be the biggest between the
base's row marker and C. The TTL will be that of C. This means that if
C expires, the view row maker will expire as well (and the row, if no
other column is keeping it alive). Note that if the base row marker
expires but not C, then the base row will still be live due to C and
we shouldn't expire the view row.
For 2), the view row timestamp will be the same as the base row
timestamp. The TTL should be set in such a way that both base and view
rows live for the same time. We thus set the view row TTL to be the
max of any other TTL in the base row. This is particularly important
in the case where the base row marker has a TTL, but a column *absent*
from the view holds a greater one.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch introduces the view_updates class, which is responsible
for generating and storing updates to a particular materialized view.
The updates will be generated from an updated base row and the
pre-existing one (if any), in later patches.
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 an utility function that creates a raw select
statement from a set of columns and a where clause. It is intended to
be used to create the prepared select statement used by the view
class.
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>
