After upgrade from 1.7 to 2.0, nodes will record a per-table schema
version which matches that on 1.7 to support the rolling upgrade. Any
later schema change (after the upgrade is done) will drop this record
from affected tables so that the per-table schema version is
recalculated. If nodes perform a schema pull (they detect schema
mismatch), then the merge will affect all tables and will wipe the
per-table schema version record from all tables, even if their schema
did not change. If then only some nodes get restarted, the restarted
nodes will load tables with the new (recalculated) per-table schema
version, while not restarted nodes will still use the 1.7 per-table
schema version. Until all nodes are restarted, writes or reads between
nodes from different groups will involve a needless exchange of schema
definition.
This will manifest in logs with repeated messages indicating schema
merge with no effect, triggered by writes:
database - Schema version changed to 85ab46cd-771d-36c9-bc37-db6d61bfa31f
database - Schema version changed to 85ab46cd-771d-36c9-bc37-db6d61bfa31f
database - Schema version changed to 85ab46cd-771d-36c9-bc37-db6d61bfa31f
The sync will be performed if the receiving shard forgets the foreign
version, which happens if it doesn't process any request referencing
it for more than 1 second.
This may impact latency of writes and reads.
The fix is to treat schema changes which drop the 1.7 per-table schema
version marker as an alter, which will switch in-memory data
structures to use the new per-table schema version immediately,
without the need for a restart.
Fixes#3394
Tests:
- dtest: schema_test.py, schema_management_test.py
- reproduced and validated the fix with run_upgrade_tests.sh from git@github.com:tgrabiec/scylla-dtest.git
- unit (release)
Message-Id: <1524764211-12868-1-git-send-email-tgrabiec@scylladb.com>
Fixes#3187
Requires seastar "inet_address: Add constructor and conversion function
from/to IPv4"
Implements support IPv6 for CQL inet data. The actual data stored will
now vary between 4 and 16 bytes. gms::inet_address has been augumented
to interop with seastar::inet_address, though of course actually trying
to use an Ipv6 address there or in any of its tables with throw badly.
Tests assuming ipv4 changed. Storing a ipv4_address should be
transparent, as it now "widens". However, since all ipv4 is
inet_address, but not vice versa, there is no implicit overloading on
the read paths. I.e. tests and system_keyspace (where we read ip
addresses from tables explicitly) are modified to use the proper type.
Message-Id: <20180424161817.26316-1-calle@scylladb.com>
When a view's PK only contains the columns that form the base's PK,
then the liveness of a particular view row is determined not only by
the base row's marker, but also by the selected and, more importantly,
unselected columns.
This patch ensures that unselected columns are considered as much as
possible, even though some limitations will still exist. In
particular, we need to represent multiple timestamps (from all the
unselected columns), but have only mechanisms to record a single
timestamp.
We also have some issues when dealing with selected column, and the
way we currently delete them. Consider the following:
create table cf (p int, c int, a int, b int, primary key (p, c))
create materialized view vcf as select a, b
from cf where p is not null and c is not null
primary key (p, c)
1) update cf using timestamp 10 set a = 1 where p = 1 and c = 1
2) delete a from cf using timestamp 11 where p = 1 and c = 1
3) update cf using timestamp 1 set a = 2 where p = 1 and c = 1
After 1), the MV should include a row with row marker @ ts10,
p = 1, c = 1, a = 1. After 2), this row should be removed.
At 3), we should add a row with row marker @ ts1, p = 1, c = 1, a = 1,
with a lower timestamp. This means that the delete should not
insert a row tombstone with timestamp @ 11, as we do now but it should
just delete the view's row marker (which exists) with ts1.
Refs #3362Fixes#3140Fixes#3361
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
When views contain a primary key column that is not part of the base
table primary key, that column determines whether the row is live or
not. We need to ensure that when that cell is dead, and thus the
derived row marker, either by normal deletion of by TTL, so is the
rest of the row.
This patch introduces the idea of shawdowing row marker. We map the
status of the regular base column in the view's PK to the view row's
marker. If this marker is dead, so is that cell in the base table, and
so should the view row become. To enforce that, a view row's dead
marker shadows the whole row if that view includes a base regular
column in its PK.
Fixes#3360
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
When a view's PK only contains the columns that form the base's PK,
then the liveness of a particular view row is determined not only by
the base row's marker, but also by the selected and, more importantly,
unselected columns. When calculating the view's row marker we need
to access those unselected columns, so we can't avoid the
read-before-write as we were doing.
Refs #3362
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
When a view's PK only contains the columns that form the base's PK,
then the liveness of a particular view row is determined not only by
the base row's marker, but also by the selected and, more importantly,
unselected columns. So, process base updates to columns unselected by
any of its views.
Refs #3362
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Not adding the partition tombstone to the current list of tombstones
may cause updates to be incorrectly generated.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Instead of lazily-initializing the regular base column in the view's
PK field, explicitly initialize it. This will be used by future
patches that don't have access to the schema when wanting to obtain
that column.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
"
Pass sstable version to parse, write and describe_type methods to make it possible to handle different versions.
For now serialization header from 3.x format is ignored.
Tests: units (release)
"
* 'haaawk/sstables3/loading_v3' of ssh://github.com/scylladb/seastar-dev:
Add test for loading the whole sstable
Add test for loading statistics
Add support for 3_x stats metadata
Pass sstable version to describe_type
Pass sstable version to write methods
metadata_type: add Serialization type
Pass sstable_version_types to parse methods
Add test for reading filter
Add test for read_summary
sstables 3.x: Add test for reading TOC
sstable: Make component_map version dependent
sstable::component_type: add operator<<
Extract sstable::component_type to separete header
Remove unused sstable::get_shared_components
sstable_version_types: add mc version
Since storage_proxy provides access to the entire cluster, a local shard
reference is sufficient. Adjust query_processor to store a reference to
just the local shard, rather than a seastar::sharded<storage_proxy> and
adjust callers.
This simplifies the code a little.
Message-Id: <20180415142656.25370-3-avi@scylladb.com>
"
Fixes to the view building process, discovered from field experience.
Tests: dtest(materialized_view_tests.py, smp=2)
"
* 'views/view-build-fixes/v1' of https://github.com/duarten/scylla:
db/view: Start view building after schema agreement
db/system_keyspace: scylla_views_builds_in_progress writes are user mem
db/view: Require configuration option to enable view building
Empty partition keys are not supported on normal tables - they cannot
be inserted or queried (surprisingly, the rules for composite
partition keys are different: all components are then allowed to be
empty). However, the (non-composite) partition key of a view could end
up being empty if that column is: a base table regular column, a
base table clustering key column, or a base table partition key column,
part of a composite key.
Fixes#3262
Refs CASSANDRA-14345
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20180403122244.10626-1-duarte@scylladb.com>
If a base table or view has been dropped in one node, but another
one hasn't yet learned about it, it starts the view build process
immediately on boot, possibly calculating unneeded view updates and
causing errors at the view replica, if that replica has already
processed the schema changes. We should thus wait for schema
agreement, even if the node is a seed.
Fixes#3328
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Treat writes to scylla_views_builds_in_progress as user memory, as the
number of writes is dependent on the amount of user data on views
(times the number of views, divided by the view building batch size).
Fixes#3325
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
View building, enabled by default, can contain or expose issues that
prevent the node from starting. In those cases, it is necessary to
disable view building such that the node can be submitted to
maintenance operations.
Fixes#3329
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
While building with -O1, I saw that the linker could not find
the vtable for named_value<log_level>. Rather than fixing up the
includes (and likely lengthening build time), fix by defining
the class as an extern template, preventing it from being
instantiated at the call site.
Message-Id: <20180401150235.13451-1-avi@scylladb.com>
Intended for use by unit tests, this patch allows synchronizing with
the end of a build for a particular view.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch adds the missing view building code to the eponymous class.
We consume from the reader associated with each base table until all
its views are built. If the reader reaches the end and there are
incomplete views, then a view was added while others were being built.
In such cases, we restart the reader to the beginning of the current
token, but not to the beginning of the token range, when the view is
added. Then, when we exhaust the reader, we simply create a new one
for the whole token range, and resume building the pending views.
We aim to be resource-conscious. On a given shard, at any given moment,
we consume at most from one reader. We also strive for fairness, in that
each build step inserts entries for the views of a different base. Each
build step reads and generates updates for batch_size rows. We lack a
controller, which could potentially allow us to go faster (to execute
multiple steps at the same time, or consume more rows per batch), and
also which would apply backpressure, so we could, for example, delay
executing a build step.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
The view_builder now uses the migration_manager to subscribe to schema
change events, and update its bookkeeping accordingly. We prefer this
to having the database call into the view_builder, as that would
create a cyclic dependency.
We serialize changes to the views of a particular base table, such
that schema changes do not interfere with the upcoming view building
code.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch introduces the view_builder class, a sharded service
responsible for building all defined materialized views. This process
entails walking over the existing data in a given base table, and using
it to calculate and insert the respective entries for one or more views.
This patch introduces only the bootstrap functionality, which is
responsible for loading the data stored in the system tables and
filling the in-memory data structures with the relevant information,
to be used in subsequent patches for the actual view building. The
interaction with the system tables is as follows.
Interaction with the tables in system_keyspace:
- When we start building a view, we add an entry to the
scylla_views_builds_in_progress system table. If the node restarts
at this point, we'll consider these newly inserted views as having
made no progress, and we'll treat them as new views;
- When we finish a build step, we update the progress of the views
that we built during this step by writing the next token to the
scylla_views_builds_in_progress table. If the node restarts here,
we'll start building the views at the token in the next_token
column.
- When we finish building a view, we mark it as completed in the
built views system table, and remove it from the in-progress system
table. Under failure, the following can happen:
* When we fail to mark the view as built, we'll redo the last
step upon node reboot;
* When we fail to delete the in-progress record, upon reboot
we'll remove this record.
A view is marked as completed only when all shards have finished
their share of the work, that is, if a view is not built, then all
shards will still have an entry in the in-progress system table;
- A view that a shard finished building, but not all other shards,
remains in the in-progress system table, with first_token ==
next_token.
Interaction with the distributed system table (view_build_status):
- When we start building a view, we mark the view build as being
in-progress;
- When we finish building a view, we mark the view as being built.
Upon failure, we ensure that if the view is in the in-progress
system table, then it may not have been written to this table. We
don't load the built views from this table when starting. When
starting, the following happens:
* If the view is in the system.built_views table and not the
in-progress system table, then it will be in view_build_status;
* If the view is in the system.built_views table and not in
this one, it will still be in the in-progress system table -
we detect this and mark it as built in this table too,
keeping the invariant;
* If the view is in this table but not in system.built_views,
then it will also be in the in-progress system table - we
don't detect this and will redo the missing step, for
simplicity.
View building is necessarily a sharded process. That means that on
restart, if the number of shards has changed, we need to calculate
the most conservative token range that has been built, and build
the remainder.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
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>
This patch introduces a distributed system keyspace, used to hold
system tables that need to be replicated across a set of replicas
(that is, can't use the LocalStrategy).
In following patches, we will use this keyspace to hold a table
containing view building status updates for each node, used to support
range movements and a new nodetool command.
Fixes#3237
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch implements an API to access the MV-related system tables,
which pertain to the view building process.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Provide a virtual reader so users can query the in-progress view table
in a way compatible with Apache Cassandra.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
When building a materialized view, we divide our work by shard, so we
need to register which shard did what work in the in-progress system
table. We also add the token we started at, which will enable some
optimizations in the view building code.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
"
Additional extension points.
* Allows wrapping commitlog file io (including hinted handoff).
* Allows system schema modification on boot, allowing extensions
to inject extensions into hardcoded schemas.
Note: to make commitlog file extensions work, we need to both
enforce we can be notified on segment delete, and thus need to
fix the old issue of hard ::unlink call in segment destructor.
Segment delete is therefore moved to a batch routine, run at
intervals/flush. Replay segments and hints are also deleted via
the commitlog object, ensuring an extension is notified (metadata).
Configurable listeneres are now allowed to inject configuration
object into the main config. I.e. a local object can, either
by becoming a "configurable" or manually, add references to
self-describing values that will be parsed from the scylla.yaml
file, effectively extending it.
All these wonderful abstractions courtesy of encryption of course.
But super generalized!
"
* 'calle/commitlog_ext' of github.com:scylladb/seastar-dev:
db::extensions: Allow extensions to modify (system) schemas
db::commitlog: Add commitlog/hints file io extension
db::commitlog: Do segment delete async + force replay delete go via CL
main/init: Change configurable callbacks and calls to allow adding opts
util::config_file: Add "add" config item overload
Allows extensions/config listeners to potentially augument
(system) schemas at boot time. This is only useful for schemas
who do not pass through system_schema tables.
Refs #2858
Push segement files to be deleted to a pending list, and process at
intervals or flush-requests (or shutdown). Note that we do _not_
indescrimenately do deletes in non-anchored tasks, because we need
to guarantee that finshed segments are fully deleted and gone on CL
shutdown, not to be mistaken for replayables.
Also make sure we delete segments replayed via commitlog call,
so IFF we add metadata processing for CL, we can clear it out.
"
Since f8613a8415 we have reader-caching
on replicas for single-partition queries. This caching works best when
all pages of a query are sent to the same replicas consistently and thus
they can reuse the cached readers there.
The propability-based nature of read-repair works against this as on any
given page a read-repair will be attempted or not based on probability.
This will cause hight drop-rates on the replicas used for read-repair as
the cached reader will not be reusable if the replica was skipped for
one or more pages.
To fix this make the repair-decision once, on the first page of the
query and store the decision in the paging-state. On all remaining
pages of the query use this stored decision.
Tests: unit-tests(release, debug), dtest(paging_advanced_tests.py)
Refs: #1865
"
* 'per_query_repair_decision/v2' of https://github.com/denesb/scylla:
Make the read-repair decision only once
storage_proxy: add coordinator_query_options and coordinator_query_result
Add query_read_repair_decision to paging-state
As yet more parameters and return-values are about to be added to all
storage_proxy::query_* methods we need a way that scales better than
changing the signatures every time. To this end we aggregate all
non-mandatory query parameters into `coordinator_query_options` and all
return values into `coordinator_query_result`.
This way new fields can be simply added to the respective structs while
the signatures of the methods themselves and their client code can
remain unchanged.
When the cluster is changed (nodes added or removed), ranges of tokens
are moved between nodes. Scylla initiates a streaming process between an
old and a new owner of the range, which can take a long time. During
that streaming time, the new owner of the range is known as a "pending node"
for this range, and all updates must go to both the old owner (in case the
movement fails!) and the pending node (in case the movement succeeds).
For materialized views, because they are ordinary tables, streaming moves
all the view's data that existed before the streaming started. But we did
not send updates done to the view *during* the streaming. A dtest
demonstrates that the new node will miss some of the view update, and will
require a repair of the view tables immediately after the cluster change
ends, which is not good. To fix that, we need to send every new update
that happens during the streaming also to the "pending node". We already
did this properly for base-table updates, but not to the view updates:
Each base table replica wrote to only one paired view table replica,
and nobody wrote to the new pending node (in case where there is one,
for the particular view token involved).
In this patch, we make sure that all view updates go also to the "pending
nodes" when there are any. We do the same thing that Cassandra does, which
is - *all* base replicas write the update to the pending node(s).
Arguably, it is inefficient that all replicas send the update to the same
node. In most cases it is enough to send it from just one base replica -
the one who is slated to be the new node's pair. I opened
https://issues.apache.org/jira/browse/CASSANDRA-14262 about this idea.
But that is an optimization. The patch as-is already fixes the bug.
Fixes#3211
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20180313171853.17283-1-nyh@scylladb.com>
buffer_size() exposes the collective size of the external memory
consumed by the mutattion-fragments in the flat reader's buffer. This
provides a basis to build basic memory accounting on. Altought this is
not the entire memory consumption of any given reader it is the most
volatile component and usually by far the largest one too.
Propagate the preferred_replicas to db::filter_for_query() and consider
them when selecting the endpoints. The algoritm for selecting the
endpoints is as follows:
* Compute the intersection of the endpoint candidates and the
preferred endpoints.
* If this yields a set of endpoints that already satisfies the CL
requirements use this set.
* Otherwise select the remaining endpoints according to the
load-balancing strategy, just like before.
preferred_replicas are added to the parameters and last_replicas are
added to the return type. The preferred replicas will be used as a hint
for the selection of the replicas to send the read requests to. The last
replicas (returned) are the replicas actually selected for the read.
This will allow queries to consistently hit the same replicas for each
page thus reusing readers created on these replicas.
For convenience a query() overload is provided that doesn't take or
return the preferred and last replicas.
This patch only adds the parameters and propagates them down to
query_singular() and query_partition_key_range(). The code to actually
use these preferred-replicas will be added in later patches.
This reason for separating this is to reduce noise and improve
reviewability for those functional changes later.
"
Adds extension points to schema/sstables to enable hooking in
stuff, like, say, something that modifies how sstable disk io
works. (Cough, cough, *encryption*)
Extensions are processed as property keywords in CQL. To add
an extension, a "module" must register it into the extensions
object on boot time. To avoid globals (and yet don't),
extensions are reachable from config (and thus from db).
Table/view tables already contain an extension element, so
we utilize this to persist config.
schema_tables tables/views from mutations now require a "context"
object (currently only extensions, but abstracted for easier
further changes.
Because of how schemas currently operate, there is a super
lame workaround to allow "schema_registry" access to config
and by extension extensions. DB, upon instansiation, calls
a thread local global "init" in schema_registry and registers
the config. It, in turn, can then call table_from_mutations
as required.
Includes the (modified) patch to encapsulate compression
into objects, mainly because it is nice to encapsulate, and
isolate a little.
"
* 'calle/extensions-v5' of github.com:scylladb/seastar-dev:
extensions: Small unit test
sstables: Process extensions on file open
sstables::types: Add optional extensions attribute to scylla metadata
sstables::disk_types: Add hash and comparator(sstring) to disk_string
schema_tables: Load/save extensions table
cql: Add schema extensions processing to properties
schema_tables: Require context object in schema load path
schema_tables: Add opaque context object
config_file_impl: Remove ostream operators
main/init: Formalize configurables + add extensions to init call
db::config: Add extensions as a config sub-object
db::extensions: Configuration object to store various extensions
cql3::statements::property_definitions: Use std::variant instead of any
sstables: Add extension type for wrapping file io
schema: Add opaque type to represent extensions
sstables::compress/compress: Make compression a virtual object
