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NEWS.txt
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PLEASE READ: MAXIMUM TTL EXPIRATION DATE NOTICE (CASSANDRA-14092)
------------------------------------------------------------------
(General upgrading instructions are available in the next section)
The maximum expiration timestamp that can be represented by the storage engine is
2038-01-19T03:14:06+00:00, which means that inserts with TTL thatl expire after
this date are not currently supported. By default, INSERTS with TTL exceeding the
maximum supported date are rejected, but it's possible to choose a different
expiration overflow policy. See CASSANDRA-14092.txt for more details.
Prior to 3.0.16 (3.0.X) and 3.11.2 (3.11.x) there was no protection against INSERTS
with TTL expiring after the maximum supported date, causing the expiration time
field to overflow and the records to expire immediately. Clusters in the 2.X and
lower series are not subject to this when assertions are enabled. Backed up SSTables
can be potentially recovered and recovery instructions can be found on the
CASSANDRA-14092.txt file.
If you use or plan to use very large TTLS (10 to 20 years), read CASSANDRA-14092.txt
for more information.
PLEASE READ: CVE-2021-44521 SCRIPTED UDF SYSTEM ACCESS (CASSANDRA-17352)
------------------------------------------------------------------------
If you have enabled scripted UDFs and run without UDF threads in cassandra.yaml:
enable_user_defined_functions_threads: false
an attacker could access java.lang.System methods and execute arbitrary code on
the machine. Disabling UDF threads is still considered insecure and not recommended.
To continue running without UDF threads you will need to set:
allow_insecure_udfs: true
and if you need access to java.lang.System for existing UDFs, set:
allow_extra_insecure_udfs: true
GENERAL UPGRADING ADVICE FOR ANY VERSION
========================================
Snapshotting is fast (especially if you have JNA installed) and takes
effectively zero disk space until you start compacting the live data
files again. Thus, best practice is to ALWAYS snapshot before any
upgrade, just in case you need to roll back to the previous version.
(Cassandra version X + 1 will always be able to read data files created
by version X, but the inverse is not necessarily the case.)
When upgrading major versions of Cassandra, you will be unable to
restore snapshots created with the previous major version using the
'sstableloader' tool. You can upgrade the file format of your snapshots
using the provided 'sstableupgrade' tool.
4.2
===
New features
------------
- Added new Mathematical CQL functions: abs, exp, log, log10 and round.
- Adds a trie-based memtable implementation, which improves memory use, garbage collection efficiency and lookup
performance. The new memtable is implemented by the TrieMemtable class and can be selected using the memtable
API, see src/java/org/apache/cassandra/db/memtable/Memtable_API.md.
- Added a new configuration cdc_on_repair_enabled to toggle whether CDC mutations are replayed through the
write path on streaming, e.g. repair. When enabled, CDC data streamed to the destination node will be written into
commit log first. When disabled, the streamed CDC data is written into SSTables just the same as normal streaming.
If this is set to false, streaming will be considerably faster however it's possible that, in extreme situations
(losing > quorum # nodes in a replica set), you may have data in your SSTables that never makes it to the CDC log.
The default is true/enabled. The configuration can be altered via JMX.
- Added support for reading the write times and TTLs of the elements of collections and UDTs, regardless of being
frozen or not. The CQL functions writetime, maxwritetime and ttl can now be applied to entire collections/UDTs,
single collection/UDT elements and slices of collection/UDT elements.
- Added a new CQL function, maxwritetime. It shows the largest unix timestamp that the data was written, similar to
its sibling CQL function, writetime.
- New Guardrails added:
- Whether ALTER TABLE commands are allowed to mutate columns
- Whether SimpleStrategy is allowed on keyspace creation or alteration
- Maximum replication factor
- Whether DROP KEYSPACE commands are allowed.
- Column value size
- It is possible to list ephemeral snapshots by nodetool listsnaphots command when flag "-e" is specified.
- Added a new flag to `nodetool profileload` and JMX endpoint to set up recurring profile load generation on specified
intervals (see CASSANDRA-17821)
- Added a new property, gossiper.loose_empty_enabled, to allow for a looser definition of "empty" when
considering the heartbeat state of another node in Gossip. This should only be used by knowledgeable
operators in the following scenarios:
Currently "empty" w/regards to heartbeat state in Gossip is very specific to a single edge case (i.e. in
isEmptyWithoutStatus() our usage of hbState() + applicationState), however there are other failure cases which
block host replacements and require intrusive workarounds and human intervention to recover from when you
have something in hbState() you don't expect. See CASSANDRA-17842 for further details.
- Added new CQL table property 'allow_auto_snapshot' which is by default true. When set to false and 'auto_snapshot: true'
in cassandra.yaml, there will be no snapshot taken when a table is truncated or dropped. When auto_snapshot in
casandra.yaml is set to false, the newly added table property does not have any effect.
- Changed default on resumable bootstrap to be disabled. Resumable bootstrap has edge cases with potential correctness
violations or data loss scenarios if nodes go down during bootstrap, tombstones are written, and operations race with
repair. As streaming is considerably faster in the 4.0+ era (as well as with zero copy streaming), the risks of
having these edge cases during a failed and resumed bootstrap are no longer deemed acceptable.
To re-enable this feature, use the -Dcassandra.reset_bootstrap_progress=false environment flag.
- Added --older-than and --older-than-timestamp options to nodetool clearsnapshot command. It is possible to
clear snapshots which are older than some period for example, "--older-than 5h" to remove
snapshots older than 5 hours and it is possible to clear all snapshots older than some timestamp, for example
--older-than-timestamp 2022-12-03T10:15:30Z.
- Cassandra logs can be viewed in the virtual table system_views.system_logs.
Please uncomment the respective appender in logback.xml file to make logs flow into this table. This feature is turned off by default.
- Added new CQL table property 'incremental_backups' which is by default true. When 'incremental_backups' property in cassandra.yaml
is set to true and table property is set to false, incremental backups for that specific table will not be done.
When 'incremental_backups' in casandra.yaml is set to false, the newly added table property does not have any effect.
Both properties have to be set to true (cassandra.yaml and table property) in order to make incremental backups.
- Added new CQL native scalar functions for collections. The new functions are mostly analogous to the existing
aggregation functions, but they operate on the elements of collection columns. The new functions are `map_keys`,
`map_values`, `collection_count`, `collection_min`, `collection_max`, `collection_sum` and `collection_avg`.
- Added compaction_properties column to system.compaction_history table and nodetool compactionhistory command
Upgrading
---------
- Ephemeral marker files for snapshots done by repairs are not created anymore,
there is a dedicated flag in snapshot manifest instead. On upgrade of a node to version 4.2, on node's start, in case there
are such ephemeral snapshots on disk, they will be deleted (same behaviour as before) and any new ephemeral snapshots
will stop to create ephemeral marker files as flag in a snapshot manifest was introduced instead.
- There were new table properties introduced called 'allow_auto_snapshot' and 'incremental_backups' (see section 'New features'). Hence, upgraded
node will be on a new schema version. Please do a rolling upgrade of nodes of a cluster to converge to one schema version.
Deprecation
-----------
- In the JMX MBean `org.apache.cassandra.db:type=RepairService` (CASSANDRA-17668):
- deprecate the getter/setter methods `getRepairSessionSpaceInMebibytes` and `setRepairSessionSpaceInMebibytes`
in favor of `getRepairSessionSpaceInMiB` and `setRepairSessionSpaceInMiB` respectively
- In the JMX MBean `org.apache.cassandra.db:type=StorageService` (CASSANDRA-17668):
- deprecate the getter/setter methods `getRepairSessionMaxTreeDepth` and `setRepairSessionMaxTreeDepth`
in favor of `getRepairSessionMaximumTreeDepth` and `setRepairSessionMaximumTreeDepth`
- deprecate the setter method `setColumnIndexSize` in favor of `setColumnIndexSizeInKiB`
- deprecate the getter/setter methods `getColumnIndexCacheSize` and `setColumnIndexCacheSize` in favor of
`getColumnIndexCacheSizeInKiB` and `setColumnIndexCacheSizeInKiB` respectively
- deprecate the getter/setter methods `getBatchSizeWarnThreshold` and `setBatchSizeWarnThreshold` in favor of
`getBatchSizeWarnThresholdInKiB` and `setBatchSizeWarnThresholdInKiB` respectively
4.1
===
New features
------------
- Added API for alternative memtable implementations. For details, see
src/java/org/apache/cassandra/db/memtable/Memtable_API.md
- Added a new guardrails framework allowing to define soft/hard limits for different user actions, such as limiting
the number of tables, columns per table or the size of collections. These guardrails are only applied to regular
user queries, and superusers and internal queries are excluded. Reaching the soft limit raises a client warning,
whereas reaching the hard limit aborts the query. In both cases a log message and a diagnostic event are emitted.
Additionally, some guardrails are not linked to specific user queries due to techincal limitations, such as
detecting the size of large collections during compaction or periodically monitoring the disk usage. These
guardrails would only emit the proper logs and diagnostic events when triggered, without aborting any processes.
Guardrails config is defined through cassandra.yaml properties, and they can be dynamically updated through the
JMX MBean `org.apache.cassandra.db:type=Guardrails`. There are guardrails for:
- Number of user keyspaces.
- Number of user tables.
- Number of columns per table.
- Number of secondary indexes per table.
- Number of materialized tables per table.
- Number of fields per user-defined type.
- Number of items in a collection .
- Number of partition keys selected by an IN restriction.
- Number of partition keys selected by the cartesian product of multiple IN restrictions.
- Allowed table properties.
- Allowed read consistency levels.
- Allowed write consistency levels.
- Collections size.
- Query page size.
- Minimum replication factor.
- Data disk usage, defined either as a percentage or as an absolute size.
- Whether user-defined timestamps are allowed.
- Whether GROUP BY queries are allowed.
- Whether the creation of secondary indexes is allowed.
- Whether the creation of uncompressed tables is allowed.
- Whether querying with ALLOW FILTERING is allowed.
- Whether DROP or TRUNCATE TABLE commands are allowed.
- Add support for the use of pure monotonic functions on the last attribute of the GROUP BY clause.
- Add floor functions that can be use to group by time range.
- Support for native transport rate limiting via native_transport_rate_limiting_enabled and
native_transport_max_requests_per_second in cassandra.yaml.
- Support for pre hashing passwords on CQL DCL commands
- Expose all client options via system_views.clients and nodetool clientstats --client-options.
- Add new nodetool compactionstats --vtable option to match the sstable_tasks vtable.
- Support for String concatenation has been added through the + operator.
- New configuration max_hints_size_per_host to limit the size of local hints files per host in mebibytes. Setting to
non-positive value disables the limit, which is the default behavior. Setting to a positive value to ensure
the total size of the hints files per host does not exceed the limit.
- Added ability to configure auth caches through corresponding `nodetool` commands.
- CDC data flushing now can be configured to be non-blocking with the configuration cdc_block_writes. Setting to true,
any writes to the CDC-enabled tables will be blocked when reaching to the limit for CDC data on disk, which is the
existing and the default behavior. Setting to false, the writes to the CDC-enabled tables will be accepted and
the oldest CDC data on disk will be deleted to ensure the size constraint.
- Top partitions based on partition size or tombstone count are now tracked per table. These partitions are stored
in a new system.top_partitions table and exposed via JMX and nodetool tablestats. The partitions are tracked
during full or validation repairs but not incremental ones since those don't include all sstables and the partition
size/tombstone count would not be correct.
- New native functions to convert unix time values into C* native types: toDate(bigint), toTimestamp(bigint),
mintimeuuid(bigint) and maxtimeuuid(bigint)
- Support for multiple permission in a single GRANT/REVOKE/LIST statement has been added. It allows to
grant/revoke/list multiple permissions using a single statement by providing a list of comma-separated
permissions.
- A new ALL TABLES IN KEYSPACE resource has been added. It allows to grant permissions for all tables and user types
in a keyspace while preventing the user to use those permissions on the keyspace itself.
- Added support for type casting in the WHERE clause components and in the values of INSERT and UPDATE statements.
- A new implementation of Paxos (named v2) has been included that improves the safety and performance of LWT operations.
Importantly, v2 guarantees linearizability across safe range movements, so users are encouraged to enable v2.
v2 also halves the number of WAN messages required to be exchanged if used on conjunction with the new Paxos Repair
mechanism (see below) and with some minor modifications to applications using LWTs.
The new implementation may be enabled at any time by setting paxos_variant: v2, and disabled by setting to v1,
and this alone will reduce the number of WAN round-trips by between one and two for reads, and one for writes.
- A new Paxos Repair mechanism has been introduced as part of Repair, that permits further reducing the number of WAN
round-trips for write LWTs. This process may be manually executed for v1 and is run automatically alongside normal
repairs for v2. Once users are running regular repairs that include paxos repairs they are encouraged to set
paxos_state_purging: repaired. Once this has been set across the cluster, users are encouraged to set their
applications to supply a Commit consistency level of ANY with their LWT write operations, saving one additional WAN
round-trip. See upgrade notes below.
- Warn/fail thresholds added to read queries notifying clients when these thresholds trigger (by
emitting a client warning or failing the query). This feature is disabled by default, scheduled
to be enabled in 4.2; it is controlled with the configuration read_thresholds_enabled,
setting to true will enable this feature. Each check has its own warn/fail thresholds, currently
tombstones (tombstone_warn_threshold, and tombstone_failure_threshold), coordinator result set
materialized size (coordinator_read_size_warn_threshold and coordinator_read_size_fail_threshold),
local read materialized heap size
(local_read_size_warn_threshold and local_read_size_fail_threshold),
and RowIndexEntry estimated memory size (row_index_read_size_warn_threshold and
row_index_read_size_fail_threshold) are supported; more checks will be added over time.
- Prior to this version, the hint system was storing a window of hints as defined by
configuration property max_hint_window_in_ms, however this window is not persistent across restarts.
For example, if a node is restarted, it will be still eligible for a hint to be sent to it because it
was down less than max_hint_window_in_ms. Hence if that node continues restarting without hint delivery completing,
hints will be sent to that node indefinitely which would occupy more and more disk space.
This behaviour was changed in CASSANDRA-14309. From now on, by default, if a node is not down longer than
max_hint_window_in_ms, there is an additional check to see if there is a hint to be delivered which is older
than max_window_in_ms. If there is, a hint is not persisted. If there is not, it is.
This behaviour might be reverted as it was in previous version by property hint_window_persistent_enabled by
setting it to false. This property is by default set to true.
- Added a new feature to allow denylisting (i.e. blocking read, write, or range read configurable) access to partition
keys in configured keyspaces and tables. See doc/operating/denylisting_partitions.rst for details on using this new
feature. Also see CASSANDRA-12106.
- Information about pending hints is now available through `nodetool listpendinghints` and `pending_hints` virtual
table.
- Added ability to invalidate auth caches through corresponding `nodetool` commands and virtual tables.
- DCL statements in audit logs will now obscure only the password if they don't fail to parse.
- Starting from 4.1 sstables support UUID based generation identifiers. They are globally unique and thus they let
the node to create sstables without any prior knowledge about the existing sstables in the data directory.
The feature is disabled by default in cassandra.yaml because once enabled, there is no easy way to downgrade.
When the node is restarted with UUID based generation identifiers enabled, each newly created sstable will have
a UUID based generation identifier and such files are not readable by previous Cassandra versions. In the future
those new identifiers will become enabled by default.
- Resetting schema behavior has changed in 4.1 so that: 1) resetting schema is prohibited when there is no live node
where the schema could be fetched from, and 2) truncating local schema keyspace is postponed to the moment when
the node receives schema from some other node.
Upgrading
---------
- `cache_load_timeout_seconds` being negative for disabled is equivalent to `cache_load_timeout` = 0 for disabled.
- `sstable_preemptive_open_interval_in_mb` being negative for disabled is equivalent to `sstable_preemptive_open_interval`
being null again. In the JMX MBean `org.apache.cassandra.db:type=StorageService`, the setter method
`setSSTablePreemptiveOpenIntervalInMB`still takes `intervalInMB` negative numbers for disabled.
- `enable_uuid_sstable_identifiers` parameter from 4.1 alpha1 was renamed to `uuid_sstable_identifiers_enabled`.
- `index_summary_resize_interval_in_minutes = -1` is equivalent to index_summary_resize_interval being set to `null` or
disabled. In the JMX MBean `org.apache.cassandra.db:type=IndexSummaryManager`, the setter method `setResizeIntervalInMinutes` still takes
`resizeIntervalInMinutes = -1` for disabled.
- min_tracked_partition_size_bytes parameter from 4.1 alpha1 was renamed to min_tracked_partition_size.
- Parameters of type data storage, duration and data rate cannot be set to Long.MAX_VALUE (former parameters of long type)
and Integer.MAX_VALUE (former parameters of int type). Those numbers are used during conversion between units to prevent
an overflow from happening. (CASSANDRA-17571)
- We added new JMX methods `setStreamThroughputMbitPerSec`, `getStreamThroughputMbitPerSec`, `setInterDCStreamThroughputMbitPerSec`,
`getInterDCStreamThroughputMbitPerSec` to the JMX MBean `org.apache.cassandra.db:type=StorageService`. They replace the now
deprecated methods `setStreamThroughputMbPerSec`, `getStreamThroughputMbPerSec`, `setInterDCStreamThroughputMbPerSec`, and
`getInterDCStreamThroughputMbPerSec`, which will be removed in a future major release.
- The config property `repair_session_space_in_mb` was wrongly advertised in previous versions that it should be set in
megabytes when it is interpreted internally in mebibytes. To reduce the confusion we added two new JMX methods
`setRepairSessionSpaceInMebibytes(int sizeInMebibytes)` and `getRepairSessionSpaceInMebibytes`. They replace the now
deprecated methods `setRepairSessionSpaceInMegabytes(int sizeInMegabytes)` and `getRepairSessionSpaceInMegabytes`, which
will be removed in a future major release.
- There is a new cassandra.yaml version 2. Units suffixes should be provided for all rates(B/s|KiB/s|MiB/s),
memory (B|KiB|MiB|GiB) and duration(d|h|m|s|ms|us|µs|ns)
parameters. List of changed parameters and details to consider during configuration setup can be
found at https://cassandra.apache.org/doc/latest/cassandra/new/configuration.html. (CASSANDRA-15234)
Backward compatibility with the old cassandra.yaml file will be in place until at least the next major version.
By default we refuse starting Cassandra with a config containing both old and new config keys for the same parameter. Start
Cassandra with -Dcassandra.allow_new_old_config_keys=true to override. For historical reasons duplicate config keys
in cassandra.yaml are allowed by default, start Cassandra with -Dcassandra.allow_duplicate_config_keys=false to disallow this.
- Many cassandra.yaml parameters' names have been changed. Full list and details to consider during configuration setup
when installing/upgrading Cassandra can be found at https://cassandra.apache.org/doc/latest/cassandra/new/configuration.html (CASSANDRA-15234)
- Negative values cannot be used for parameters of type data rate, duration and data storage with both old and new cassandra.yaml version.
Only exception is if you use old cassandra.yaml, pre-CASSANDRA-15234 - then -1 or other negative values which were advertised as an option
to disable config parameters in the old cassandra.yaml are still used. Those are probably converted to null value with the new cassandra.yaml,
as written in the new cassandra.yaml version and docs.
- Before you upgrade, if you are using `cassandra.auth_bcrypt_gensalt_log2_rounds` property,
confirm it is set to value lower than 31 otherwise Cassandra will fail to start. See CASSANDRA-9384
for further details. You also need to regenerate passwords for users for who the password
was created while the above property was set to be more than 30 otherwise they will not be able to log in.
- JNA library was updated from 5.6.0 to 5.9.0. In version 5.7.0, Darwin support for M1 devices
was fixed but prebuild native library for Darwin x86 (32bit Java on Mac OS) was removed.
- The config properties for setting the streaming throughput `stream_throughput_outbound_megabits_per_sec` and
`inter_dc_stream_throughput_outbound_megabits_per_sec` were incorrectly interpreted as mebibits. This has
been fixed by CASSANDRA-17243, so the values for these properties will now indicate a throughput ~4.6% lower than
what was actually applied in previous versions. This also affects the setters and getters for these properties in
the JMX MBean `org.apache.cassandra.db:type=StorageService` and the nodetool commands `set/getstreamthroughput`
and `set/getinterdcstreamthroughput`.
- Steps for upgrading Paxos
- Set paxos_variant: v2 across the cluster. This may be set via JMX, but should also be written
persistently to any yaml.
- Ensure paxos repairs are running regularly, either as part of normal incremental repair workflows or on their
own separate schedule. These operations are cheap and better to run frequently (e.g. once per hour)
- Set paxos_state_purging: repaired across the cluster. This may be set via JMX, but should also be written
persistently to any yaml. NOTE: once this has been set, you must not restore paxos_state_purging: legacy. If
this setting must be disabled you must instead set paxos_state_purging: gc_grace. This may be necessary if
paxos repairs must be disabled for some reason on an extended basis, but in this case your applications must
restore default commit consistency to ensure correctness.
- Applications may now safely be updated to use ANY commit consistency level (or LOCAL_QUORUM, as preferred).
Uncontended writes should now take 2 round-trips, and uncontended reads should typically take one round-trip.
- A required [f|force] flag has been added to both "nodetool verify" and the standalone "sstableverify" tools.
These tools have some subtleties and should not be used unless the operator is familiar with what they do
and do not do, as well as the edge cases associated with their use.
NOTE: ANY SCRIPTS THAT RELY ON sstableverify OR nodetool verify WILL STOP WORKING UNTIL MODIFIED.
Please see CASSANDRA-17017 for details: https://issues.apache.org/jira/browse/CASSANDRA-17017
- `MutationExceededMaxSizeException` thrown when a mutation exceeds `max_mutation_size` inherits
from `InvalidRequestException` instead of `RuntimeException`. See CASSANDRA-17456 for details.
Deprecation
-----------
- In the command line options for `org.apache.cassandra.tools.LoaderOptions`: deprecate the `-t`, `--throttle`,
`-idct`, and `--inter-dc-throttle` options for setting the throttle and inter-datacenter throttle options in
Mbps. Instead, users are instructed to use the `--throttle-mib`, and `--inter-dc-throttle-mib` for setting the
throttling options in MiB/s. Additionally, in the loader options builder
`org.apache.cassandra.tools.LoaderOptions$Builder`: deprecate the `throttle(int)`, `interDcThrottle(int)`,
`entireSSTableThrottle(int)`, and the `entireSSTableInterDcThrottle(int)` methods.
- In the JMX MBean `org.apache.cassandra.db:type=StorageService`: deprecate getter method `getStreamThroughputMbitPerSec`
in favor of getter method `getStreamThroughputMbitPerSecAsDouble`; deprecate getter method `getStreamThroughputMbPerSec`
in favor of getter methods `getStreamThroughputMebibytesPerSec` and `getStreamThroughputMebibytesPerSecAsDouble`;
deprecate getter method `getInterDCStreamThroughputMbitPerSec` in favor of getter method `getInterDCStreamThroughputMbitPerSecAsDouble`;
deprecate getter method `getInterDCStreamThroughputMbPerSec` in favor of getter methods `getInterDCStreamThroughputMebibytesPerSecAsDouble`;
deprecate getter method `getCompactionThroughputMbPerSec` in favor of getter methods `getCompactionThroughtputMibPerSecAsDouble`
and `getCompactionThroughtputBytesPerSec`; deprecate setter methods `setStreamThroughputMbPerSec` and `setStreamThroughputMbitPerSec`
in favor of `setStreamThroughputMebibytesPerSec`; deprecate setter methods `setInterDCStreamThroughputMbitPerSec` and
`setInterDCStreamThroughputMbPerSec` in favor of `setInterDCStreamThroughputMebibytesPerSec`. The deprecated JMX methods
may return a rounded value so if precision is important, you want to use the new getters. While those deprecated JMX getters
will return a rounded number, the nodetool commands `getstreamthroughput` and `getinterdcstreamthroughput`
will throw Runtime Exceptions advising to use the new -d flag in case an integer cannot be returned. See CASSANDRA-17725 for further details.
- Deprecate public method `setRate(final double throughputMbPerSec)` in `Compaction Manager` in favor of
`setRateInBytes(final double throughputBytesPerSec)`
- `withBufferSizeInMB(int size)` in `StressCQLSSTableWriter.Builder` class is deprecated in favor of `withBufferSizeInMiB(int size)`
No change of functionality in the new one, only name change for clarity in regards to units and to follow naming
standartization.
- `withBufferSizeInMB(int size)` in `CQLSSTableWriter.Builder` class is deprecated in favor of `withBufferSizeInMiB(int size)`
No change of functionality in the new one, only name change for clarity in regards to units and to follow naming
standartization.
- The properties `keyspace_count_warn_threshold` and `table_count_warn_threshold` in cassandra.yaml have been
deprecated in favour of the new `guardrails.keyspaces` and `guardrails.tables` properties and will be removed
in a subsequent major version. This also affects the setters and getters for those properties in the JMX MBean
`org.apache.cassandra.db:type=StorageService`, which are equally deprecated in favour of the analogous methods
in the JMX MBean `org.apache.cassandra.db:type=Guardrails`. See CASSANDRA-17195 for further details.
- The functionality behind the property `windows_timer_interval` was removed as part of CASSANDRA-16956. The
property is still present but it is deprecated and it is just a place-holder to prevent breaking upgrades. This
property is expected to be fully removed in the next major release of Cassandra.
4.0
===
New features
------------
- Full support for Java 11, it is not experimental anymore.
- The data of the system keyspaces using a local strategy (at the exception of the system.batches,
system.paxos, system.compaction_history, system.prepared_statements and system.repair tables)
is now stored by default in the first data directory, instead of being distributed among all
the data directories. This approach will allow the server to tolerate the failure of the other disks.
To ensure that a disk failure will not bring a node down, it is possible to use the system_data_file_directory
yaml property to store the local system keyspaces data on a directory that provides redundancy.
On node startup the local system keyspaces data will be automatically migrated if needed to the
correct location.
- Nodes will now bootstrap all intra-cluster connections at startup by default and wait
10 seconds for the all but one node in the local data center to be connected and marked
UP in gossip. This prevents nodes from coordinating requests and failing because they
aren't able to connect to the cluster fast enough. block_for_peers_timeout_in_secs in
cassandra.yaml can be used to configure how long to wait (or whether to wait at all)
and block_for_peers_in_remote_dcs can be used to also block on all but one node in
each remote DC as well. See CASSANDRA-14297 and CASSANDRA-13993 for more information.
- *Experimental* support for Transient Replication and Cheap Quorums introduced by CASSANDRA-14404
The intended audience for this functionality is expert users of Cassandra who are prepared
to validate every aspect of the database for their application and deployment practices. Future
releases of Cassandra will make this feature suitable for a wider audience.
- *Experimental* support for Java 11 has been added. JVM options that differ between or are
specific for Java 8 and 11 have been moved from jvm.options into jvm8.options and jvm11.options.
IMPORTANT: Running C* on Java 11 is *experimental* and do it at your own risk.
- LCS now respects the max_threshold parameter when compacting - this was hard coded to 32
before, but now it is possible to do bigger compactions when compacting from L0 to L1.
This also applies to STCS-compactions in L0 - if there are more than 32 sstables in L0
we will compact at most max_threshold sstables in an L0 STCS compaction. See CASSANDRA-14388
for more information.
- There is now an option to automatically upgrade sstables after Cassandra upgrade, enable
either in `cassandra.yaml:automatic_sstable_upgrade` or via JMX during runtime. See
CASSANDRA-14197.
- `nodetool refresh` has been deprecated in favour of `nodetool import` - see CASSANDRA-6719
for details
- An experimental option to compare all merkle trees together has been added - for example, in
a 3 node cluster with 2 replicas identical and 1 out-of-date, with this option enabled, the
out-of-date replica will only stream a single copy from up-to-date replica. Enable it by adding
"-os" to nodetool repair. See CASSANDRA-3200.
- The currentTimestamp, currentDate, currentTime and currentTimeUUID functions have been added.
See CASSANDRA-13132
- Support for arithmetic operations between `timestamp`/`date` and `duration` has been added.
See CASSANDRA-11936
- Support for arithmetic operations on number has been added. See CASSANDRA-11935
- Preview expected streaming required for a repair (nodetool repair --preview), and validate the
consistency of repaired data between nodes (nodetool repair --validate). See CASSANDRA-13257
- Support for selecting Map values and Set elements has been added for SELECT queries. See CASSANDRA-7396
- Change-Data-Capture has been modified to make CommitLogSegments available
immediately upon creation via hard-linking the files. This means that incomplete
segments will be available in cdc_raw rather than fully flushed. See documentation
and CASSANDRA-12148 for more detail.
- The initial build of materialized views can be parallelized. The number of concurrent builder
threads is specified by the property `cassandra.yaml:concurrent_materialized_view_builders`.
This property can be modified at runtime through both JMX and the new `setconcurrentviewbuilders`
and `getconcurrentviewbuilders` nodetool commands. See CASSANDRA-12245 for more details.
- There is now a binary full query log based on Chronicle Queue that can be controlled using
nodetool enablefullquerylog, disablefullquerylog, and resetfullquerylog. The log
contains all queries invoked, approximate time they were invoked, any parameters necessary
to bind wildcard values, and all query options. A human readable version of the log can be
dumped or tailed using the new bin/fqltool utility. The full query log is designed to be safe
to use in production and limits utilization of heap memory and disk space with limits
you can specify when enabling the log.
See nodetool and fqltool help text for more information.
- SSTableDump now supports the -l option to output each partition as it's own json object
See CASSANDRA-13848 for more detail
- Metric for coordinator writes per table has been added. See CASSANDRA-14232
- Nodetool cfstats now has options to sort by various metrics as well as limit results.
- Operators can restrict login user activity to one or more datacenters. See `network_authorizer`
in cassandra.yaml, and the docs for create and alter role statements. CASSANDRA-13985
- Roles altered from login=true to login=false will prevent existing connections from executing any
statements after the cache has been refreshed. CASSANDRA-13985
- Support for audit logging of database activity. If enabled, logs every incoming
CQL command request, Authentication (successful as well as unsuccessful login) to a node.
- Faster streaming of entire SSTables using ZeroCopy APIs. If enabled, Cassandra will use stream
entire SSTables, significantly speeding up transfers. Any streaming related operations will see
corresponding improvement. See CASSANDRA-14556.
- NetworkTopologyStrategy now supports auto-expanding the replication_factor
option into all available datacenters at CREATE or ALTER time. For example,
specifying replication_factor: 3 translates to three replicas in every
datacenter. This auto-expansion will _only add_ datacenters for safety.
See CASSANDRA-14303 for more details.
- Added Python 3 support so cqlsh and cqlshlib is now compatible with Python 2.7 and Python 3.6.
Added --python option to cqlsh so users can specify the path to their chosen Python interpreter.
See CASSANDRA-10190 for details.
- Support for server side DESCRIBE statements has been added. See CASSANDRA-14825
- It is now possible to rate limit snapshot creation/clearing. See CASSANDRA-13019
- Authentication reads and writes have been changed from a mix of ONE, LOCAL_ONE, and QUORUM
to LOCAL_QUORUM on reads and EACH_QUORUM on writes. This is configurable via cassandra.yaml with
auth_read_consistency_level and auth_write_consistency_level respectively. See CASSANDRA-12988.
Upgrading
---------
- If you were on 4.0.1 - 4.0.5 and if you haven't set the compaction_thoroughput_mb_per_sec in your 4.0 cassandra.yaml
file but you relied on the internal default value,then compaction_throughput_mb_per_sec was equal to an old default
value of 16MiB/s in Cassandra 4.0. After CASSANDRA-17790 this is changed to 64MiB/s to match the default value in
cassandra.yaml. If you prefer the old one of 16MiB/s, you need to set it explicitly in your cassandra.yaml file.
- otc_coalescing_strategy, otc_coalescing_window_us, otc_coalescing_enough_coalesced_messages,
otc_backlog_expiration_interval_ms are deprecated and will be removed at earliest with next major release.
otc_coalescing_strategy is disabled since 3.11.
- As part of the Internode Messaging improvement work in CASSANDRA-15066, internode_send_buff_size_in_bytes and
internode_recv_buff_size_in_bytes were renamed to internode_socket_send_buffer_size_in_bytes and
internode_socket_receive_buffer_size_in_bytes. To support upgrades pre-4.0, we add backward compatibility and
currently both old and new names should work. Cassandra 4.0.0 and Cassandra 4.0.1 work ONLY with the new names
(They weren't updated in cassandra.yaml though).
- DESCRIBE|DESC was moved to server side in Cassandra 4.0. As a consequence DESRIBE|DESC will not work in cqlsh 6.0.0
being connected to earlier major Cassandra versions where DESCRIBE does not exist server side.
- cqlsh shell startup script now prefers 'python3' before 'python' when identifying a runtime.
- As part of the Internode Messaging improvement work in CASSANDRA-15066, matching response verbs for every request
verb were introduced and verbs were renamed. DroppedMessageMetrics pre-4.0 are now available with _REQ suffix. As
part of CASSANDRA-16083, we added DroppedMessageMetrics backward compatibility layer which exposes the metrics with
their old names too. Only the value for verbs READ and RANGE_SLICE will differ from the same metrics in 3.11 as it
does not include anymore the responses dropped, only the requests. After being deprecated in 3.11 PAGED_RANGE was
fully removed in 4.0. ConditionNotMet metric has been moved under scope CASClientWriteRequestMetrtic but as part of
CASSANDRA-16083, backward compatibility layer was added so it can be still exposed under the old 3.11 scope.
- Native protocol v5 is promoted from beta in this release. The wire format has changed
significantly and users should take care to ensure client drivers are upgraded to a version
with support for the final v5 format, if currently connecting over v5-beta. (CASSANDRA-15299, CASSANDRA-14973)
- Cassandra removed support for the OldNetworkTopologyStrategy. Before upgrading you will need to change the
replication strategy for the keyspaces using this strategy to the NetworkTopologyStrategy. (CASSANDRA-13990)
- Sstables for tables using with a frozen UDT written by C* 3.0 appear as corrupted.
Background: The serialization-header in the -Statistics.db sstable component contains the type information
of the table columns. C* 3.0 write incorrect type information for frozen UDTs by omitting the
"frozen" information. Non-frozen UDTs were introduced by CASSANDRA-7423 in C* 3.6. Since then, the missing
"frozen" information leads to deserialization issues that result in CorruptSSTableExceptions, potentially other
exceptions as well.
As a mitigation, the sstable serialization-headers are rewritten to contain the missing "frozen" information for
UDTs once, when an upgrade from C* 3.0 is detected. This migration does not touch snapshots or backups.
The sstablescrub tool now performs a check of the sstable serialization-header against the schema. A mismatch of
the types in the serialization-header and the schema will cause sstablescrub to error out and stop by default.
See the new `-e` option. `-e off` disables the new validation code. `-e fix` or `-e fix-only`, e.g.
`sstablescrub -e fix keyspace table`, will validate the serialization-header, rewrite the non-frozen UDTs
in the serialzation-header to frozen UDTs, if that matches the schema, and continue with scrub.
See `sstablescrub -h`.
(CASSANDRA-15035)
- CASSANDRA-13241 lowered the default chunk_lengh_in_kb for compresesd tables from
64kb to 16kb. For highly compressible data this can have a noticeable impact
on space utilization. You may want to consider manually specifying this value.
- Additional columns have been added to system_distributed.repair_history,
system_traces.sessions and system_traces.events. As a result select queries
against these tables - including queries against tracing tables performed
automatically by the drivers and cqlsh - will fail and generate an error in the log
during upgrade when the cluster is mixed version. On 3.x side this will also lead
to broken internode connections and lost messages.
Cassandra versions 3.0.20 and 3.11.6 pre-add these columns (see CASSANDRA-15385),
so please make sure to upgrade to those versions or higher before upgrading to
4.0 for query tracing to not cause any issues during the upgrade to 4.0.
- Timestamp ties between values resolve differently: if either value has a TTL,
this value always wins. This is to provide consistent reconciliation before
and after the value expires into a tombstone.
- Support for legacy auth tables in the system_auth keyspace (users,
permissions, credentials) and the migration code has been removed. Migration
of these legacy auth tables must have been completed before the upgrade to
4.0 and the legacy tables must have been removed. See the 'Upgrading' section
for version 2.2 for migration instructions.
- Cassandra 4.0 removed support for the deprecated Thrift interface. Amongst
other things, this implies the removal of all yaml options related to thrift
('start_rpc', rpc_port, ...).
- Cassandra 4.0 removed support for any pre-3.0 format. This means you
cannot upgrade from a 2.x version to 4.0 directly, you have to upgrade to
a 3.0.x/3.x version first (and run upgradesstable). In particular, this
mean Cassandra 4.0 cannot load or read pre-3.0 sstables in any way: you
will need to upgrade those sstable in 3.0.x/3.x first.
- Upgrades from 3.0.x or 3.x are supported since 3.0.13 or 3.11.0, previous
versions will causes issues during rolling upgrades (CASSANDRA-13274).
- Cassandra will no longer allow invalid keyspace replication options, such
as invalid datacenter names for NetworkTopologyStrategy. Operators MUST
add new nodes to a datacenter before they can set set ALTER or CREATE
keyspace replication policies using that datacenter. Existing keyspaces
will continue to operate, but CREATE and ALTER will validate that all
datacenters specified exist in the cluster.
- Cassandra 4.0 fixes a problem with incremental repair which caused repaired
data to be inconsistent between nodes. The fix changes the behavior of both
full and incremental repairs. For full repairs, data is no longer marked
repaired. For incremental repairs, anticompaction is run at the beginning
of the repair, instead of at the end. If incremental repair was being used
prior to upgrading, a full repair should be run after upgrading to resolve
any inconsistencies.
- Config option index_interval has been removed (it was deprecated since 2.0)
- Deprecated repair JMX APIs are removed.
- The version of snappy-java has been upgraded to 1.1.2.6
- the miniumum value for internode message timeouts is 10ms. Previously, any
positive value was allowed. See cassandra.yaml entries like
read_request_timeout_in_ms for more details.
- Cassandra 4.0 allows a single port to be used for both secure and insecure
connections between cassandra nodes (CASSANDRA-10404). See the yaml for
specific property changes, and see the security doc for full details.
- Due to the parallelization of the initial build of materialized views,
the per token range view building status is stored in the new table
`system.view_builds_in_progress`. The old table `system.views_builds_in_progress`
is no longer used and can be removed. See CASSANDRA-12245 for more details.
- Config option commitlog_sync_batch_window_in_ms has been deprecated as it's
documentation has been incorrect and the setting itself near useless.
Batch mode remains a valid commit log mode, however.
- There is a new commit log mode, group, which is similar to batch mode
but blocks for up to a configurable number of milliseconds between disk flushes.
- nodetool clearsnapshot now required the --all flag to remove all snapshots.
Previous behavior would delete all snapshots by default.
- Nodes are now identified by a combination of IP, and storage port.
Existing JMX APIs, nodetool, and system tables continue to work
and accept/return just an IP, but there is a new
version of each that works with the full unambiguous identifier.
You should prefer these over the deprecated ambiguous versions that only
work with an IP. This was done to support multiple instances per IP.
Additionally we are moving to only using a single port for encrypted and
unencrypted traffic and if you want multiple instances per IP you must
first switch encrypted traffic to the storage port and not a separate
encrypted port. If you want to use multiple instances per IP
with SSL you will need to use StartTLS on storage_port and set
outgoing_encrypted_port_source to gossip outbound connections
know what port to connect to for each instance. Before changing
storage port or native port at nodes you must first upgrade the entire cluster
and clients to 4.0 so they can handle the port not being consistent across
the cluster.
- Names of AWS regions/availability zones have been cleaned up to more correctly
match the Amazon names. There is now a new option in conf/cassandra-rackdc.properties
that lets users enable the correct names for new clusters, or use the legacy
names for existing clusters. See conf/cassandra-rackdc.properties for details.
- Background repair has been removed. dclocal_read_repair_chance and
read_repair_chance table options have been removed and are now rejected.
See CASSANDRA-13910 for details.
- Internode TCP connections that do not ack segments for 30s will now
be automatically detected and closed via the Linux TCP_USER_TIMEOUT
socket option. This should be exceedingly rare, but AWS networks (and
other stateful firewalls) apparently suffer from this issue. You can
tune the timeouts on TCP connection and segment ack via the
`cassandra.yaml:internode_tcp_connect_timeout_in_ms` and
`cassandra.yaml:internode_tcp_user_timeout_in_ms` options respectively.
See CASSANDRA-14358 for details.
- repair_session_space_in_mb setting has been added to cassandra.yaml to allow operators to reduce
merkle tree size if repair is creating too much heap pressure. The repair_session_max_tree_depth
setting added in 3.0.19 and 3.11.5 is deprecated in favor of this setting. See CASSANDRA-14096
- The flags 'enable_materialized_views' and 'enable_sasi_indexes' in cassandra.yaml
have been set as false by default. Operators should modify them to allow the
creation of new views and SASI indexes, the existing ones will continue working.
See CASSANDRA-14866 for details.
- CASSANDRA-15216 - The flag 'cross_node_timeout' has been set as true by default.
This change is done under the assumption that users have setup NTP on
their clusters or otherwise synchronize their clocks, and that clocks are
mostly in sync, since this is a requirement for general correctness of
last write wins.
- CASSANDRA-15257 removed the joda time dependency. Any time formats
passed will now need to conform to java.time.format.DateTimeFormatter.
Most notably, days and months must be two digits, and years exceeding
four digits need to be prefixed with a plus or minus sign.
- cqlsh now returns a non-zero code in case of errors. This is a backward incompatible change so it may
break existing scripts that rely on the current behavior. See CASSANDRA-15623 for more details.
- Updated the default compaction_throughput_mb_per_sec to to 64. The original
default (16) was meant for spinning disk volumes. See CASSANDRA-14902 for details.
- Custom compaction strategies must now handle getting sstables added/removed notifications for
sstables already added/removed - see CASSANDRA-14103 for details.
- Support for JNA with glibc 2.6 and earlier has been removed. Centos 5, Debian 4, and Ubuntu 7.10 operating systems
must be first upgraded. See CASSANDRA-16212 for more.
- In cassandra.yaml, when using vnodes num_tokens must be defined if initial_token is defined.
If it is not defined, or not equal to the numbers of tokens defined in initial_tokens,
the node will not start. See CASSANDRA-14477 for details.
- CASSANDRA-13701 To give a better out of the box experience, the default 'num_tokens'
value has been changed from 256 to 16 for reasons described in
https://cassandra.apache.org/doc/latest/getting_started/production.html#tokens
'allocate_tokens_for_local_replication_factor' is also uncommented and set to 3.
Please note when upgrading that if the 'num_tokens' value is different than what you have
configured, the upgraded node will refuse to start. Also note that if a new node joining
the cluster has a different value for 'num_tokens' than the rest of the datacenter,
the new node will be responsible for a different amount of data than the rest of the datacenter.
Deprecation
-----------
- JavaScript user-defined functions have been deprecated. They are planned for removal
in the next major release. (CASSANDRA-17280)
- The JMX MBean org.apache.cassandra.metrics:type=Streaming,name=ActiveOutboundStreams has been
deprecated and will be removed in a subsequent major version. This metric was not updated since several version
already.
- The JMX MBean org.apache.cassandra.db:type=BlacklistedDirectories has been
deprecated in favor of org.apache.cassandra.db:type=DisallowedDirectories
and will be removed in a subsequent major version.
- cqlsh support of 2.7 is deprecated and will warn when running with Python 2.7.
ALTER ... DROP COMPACT STORAGE
------------------------------
- Following a discussion regarding concerns about the safety of the 'ALTER ... DROP COMPACT STORAGE' statement,
the C* development community does not recommend its use in production and considers it experimental
(see https://www.mail-archive.com/dev@cassandra.apache.org/msg16789.html).
- An 'enable_drop_compact_storage' flag has been added to cassandra.yaml to allow operators to prevent its use.
Materialized Views
-------------------
- Following a discussion regarding concerns about the design and safety of Materialized Views, the C* development
community no longer recommends them for production use, and considers them experimental. Warnings messages will
now be logged when they are created. (See https://www.mail-archive.com/dev@cassandra.apache.org/msg11511.html)
- An 'enable_materialized_views' flag has been added to cassandra.yaml to allow operators to prevent creation of
views
- CREATE MATERIALIZED VIEW syntax has become stricter. Partition key columns are no longer implicitly considered
to be NOT NULL, and no base primary key columns get automatically included in view definition. You have to
specify them explicitly now.
Windows Support Removed
-----------------------
- Due to the lack of maintenance and testing, Windows support is removed from this version onward. The developers
who use Windows 10 still can run Apache Cassandra locally using WSL2 (Windows Subsystem for Linux version 2),
Docker for Windows, or virtualization platform like Hyper-V and VirtualBox.
3.11.10
======
Upgrading
---------
- This release fix a correctness issue with SERIAL reads, and LWT writes that do not apply.
Unfortunately, this fix has a performance impact on read performance at the SERIAL or
LOCAL_SERIAL consistency levels. For heavy users of such SERIAL reads, the performance
impact may be noticeable and may also result in an increased of timeouts. For that
reason, a opt-in system property has been added to disable the fix:
-Dcassandra.unsafe.disable-serial-reads-linearizability=true
Use this flag at your own risk as it revert SERIAL reads to the incorrect behavior of
previous versions. See CASSANDRA-12126 for details.
- SASI's `max_compaction_flush_memory_in_mb` setting was previously getting interpreted in bytes. From 3.11.8
it is correctly interpreted in megabytes, but prior to 3.11.10 previous configurations of this setting will
lead to nodes OOM during compaction. From 3.11.10 previous configurations will be detected as incorrect,
logged, and the setting reverted to the default value of 1GB. It is up to the user to correct the setting
after an upgrade, via dropping and recreating the index. See CASSANDRA-16071 for details.
3.11.6
======
Upgrading
---------
- Sstables for tables using with a frozen UDT written by C* 3.0 appear as corrupted.
Background: The serialization-header in the -Statistics.db sstable component contains the type information
of the table columns. C* 3.0 write incorrect type information for frozen UDTs by omitting the
"frozen" information. Non-frozen UDTs were introduced by CASSANDRA-7423 in C* 3.6. Since then, the missing
"frozen" information leads to deserialization issues that result in CorruptSSTableExceptions, potentially other
exceptions as well.
As a mitigation, the sstable serialization-headers are rewritten to contain the missing "frozen" information for
UDTs once, when an upgrade from C* 3.0 is detected. This migration does not touch snapshots or backups.
The sstablescrub tool now performs a check of the sstable serialization-header against the schema. A mismatch of
the types in the serialization-header and the schema will cause sstablescrub to error out and stop by default.
See the new `-e` option. `-e off` disables the new validation code. `-e fix` or `-e fix-only`, e.g.
`sstablescrub -e fix keyspace table`, will validate the serialization-header, rewrite the non-frozen UDTs
in the serialzation-header to frozen UDTs, if that matches the schema, and continue with scrub.
See `sstablescrub -h`.
(CASSANDRA-15035)
- repair_session_max_tree_depth setting has been added to cassandra.yaml to allow operators to reduce
merkle tree size if repair is creating too much heap pressure. See CASSANDRA-14096 for details.
3.11.5
======
Experimental features
---------------------
- An 'enable_sasi_indexes' flag, true by default, has been added to cassandra.yaml to allow operators to prevent
the creation of new SASI indexes, which are considered experimental and are not recommended for production use.
(See https://www.mail-archive.com/dev@cassandra.apache.org/msg13582.html)
- The flags 'enable_sasi_indexes' and 'enable_materialized_views' have been grouped under an experimental features
section in cassandra.yaml.
3.11.4
======
Upgrading
---------
- The order of static columns in SELECT * has been fixed to match that of 2.0 and 2.1 - they are now sorted
alphabetically again, by their name, just like regular columns are. If you use prepared statements and
SELECT * queries, and have both simple and collection static columns in those tables, and are upgrading from an
earlier 3.0 version, then you might be affected by this change. Please see CASSANDRA-14638 for details.
3.11.3
=====
Upgrading
---------
- Materialized view users upgrading from 3.0.15 (3.0.X series) or 3.11.1 (3.11.X series) and later that have performed range movements (join, decommission, move, etc),
should run repair on the base tables, and subsequently on the views to ensure data affected by CASSANDRA-14251 is correctly propagated to all replicas.
- Changes to bloom_filter_fp_chance will no longer take effect on existing sstables when the node is restarted. Only
compactions/upgradesstables regenerates bloom filters and Summaries sstable components. See CASSANDRA-11163
3.11.2
======
Upgrading
---------
- See MAXIMUM TTL EXPIRATION DATE NOTICE above.
- Cassandra is now relying on the JVM options to properly shutdown on OutOfMemoryError. By default it will
rely on the OnOutOfMemoryError option as the ExitOnOutOfMemoryError and CrashOnOutOfMemoryError options
are not supported by the older 1.7 and 1.8 JVMs. A warning will be logged at startup if none of those JVM
options are used. See CASSANDRA-13006 for more details
- Cassandra is not logging anymore by default an Heap histogram on OutOfMemoryError. To enable that behavior
set the 'cassandra.printHeapHistogramOnOutOfMemoryError' System property to 'true'. See CASSANDRA-13006
for more details.
3.11.1
======
Upgrading
---------
- Creating Materialized View with filtering on non-primary-key base column
(added in CASSANDRA-10368) is disabled, because the liveness of view row
is depending on multiple filtered base non-key columns and base non-key
column used in view primary-key. This semantic cannot be supported without
storage format change, see CASSANDRA-13826. For append-only use case, you
may still use this feature with a startup flag: "-Dcassandra.mv.allow_filtering_nonkey_columns_unsafe=true"
Compact Storage (only when upgrading from 3.X or any version lower than 3.0.15)
---------------
- Starting version 4.0, Thrift is no longer supported.
Starting version 5.0, COMPACT STORAGE will no longer be supported.
'ALTER ... DROP COMPACT STORAGE' statement makes Compact Tables CQL-compatible,
exposing internal structure of Thrift/Compact Tables. You can find more details
on exposed internal structure under:
http://cassandra.apache.org/doc/latest/cql/appendices.html#appendix-c-dropping-compact-storage
For uninterrupted cluster upgrades, drivers now support 'NO_COMPACT' startup option.
Supplying this flag will have same effect as 'DROP COMPACT STORAGE', but only for the
current connection.
In order to upgrade, clients supporting a non-compact schema view can be rolled out
gradually. When all the clients are updated 'ALTER ... DROP COMPACT STORAGE' can be
executed. After dropping compact storage, ’NO_COMPACT' option will have no effect
after that.
Materialized Views
-------------------
Materialized Views (only when upgrading from any version lower than 3.0.15 (3.0 series) or 3.11.1 (3.X series))
---------------------------------------------------------------------------------------
- Cassandra will no longer allow dropping columns on tables with Materialized Views.
- A change was made in the way the Materialized View timestamp is computed, which
may cause an old deletion to a base column which is view primary key (PK) column
to not be reflected in the view when repairing the base table post-upgrade. This
condition is only possible when a column deletion to an MV primary key (PK) column
not present in the base table PK (via UPDATE base SET view_pk_col = null or DELETE
view_pk_col FROM base) is missed before the upgrade and received by repair after the upgrade.
If such column deletions are done on a view PK column which is not a base PK, it's advisable
to run repair on the base table of all nodes prior to the upgrade. Alternatively it's possible
to fix potential inconsistencies by running repair on the views after upgrade or drop and
re-create the views. See CASSANDRA-11500 for more details.
- Removal of columns not selected in the Materialized View (via UPDATE base SET unselected_column
= null or DELETE unselected_column FROM base) may not be properly reflected in the view in some
situations so we advise against doing deletions on base columns not selected in views
until this is fixed on CASSANDRA-13826.
3.11.0
======
Upgrading
---------
- Creating Materialized View with filtering on non-primary-key base column
(added in CASSANDRA-10368) is disabled, because the liveness of view row
is depending on multiple filtered base non-key columns and base non-key
column used in view primary-key. This semantic cannot be supported without
storage format change, see CASSANDRA-13826. For append-only use case, you
may still use this feature with a startup flag: "-Dcassandra.mv.allow_filtering_nonkey_columns_unsafe=true"
- The NativeAccessMBean isAvailable method will only return true if the
native library has been successfully linked. Previously it was returning
true if JNA could be found but was not taking into account link failures.
- Primary ranges in the system.size_estimates table are now based on the keyspace
replication settings and adjacent ranges are no longer merged (CASSANDRA-9639).
- In 2.1, the default for otc_coalescing_strategy was 'DISABLED'.
In 2.2 and 3.0, it was changed to 'TIMEHORIZON', but that value was shown
to be a performance regression. The default for 3.11.0 and newer has
been reverted to 'DISABLED'. Users upgrading from Cassandra 2.2 or 3.0 should
be aware that the default has changed.
- The StorageHook interface has been modified to allow to retrieve read information from
SSTableReader (CASSANDRA-13120).
3.10
====
New features
------------
- New `DurationType` (cql duration). See CASSANDRA-11873
- Runtime modification of concurrent_compactors is now available via nodetool
- Support for the assignment operators +=/-= has been added for update queries.
- An Index implementation may now provide a task which runs prior to joining
the ring. See CASSANDRA-12039
- Filtering on partition key columns is now also supported for queries without
secondary indexes.
- A slow query log has been added: slow queries will be logged at DEBUG level.
For more details refer to CASSANDRA-12403 and slow_query_log_timeout_in_ms
in cassandra.yaml.
- Support for GROUP BY queries has been added.
- A new compaction-stress tool has been added to test the throughput of compaction
for any cassandra-stress user schema. see compaction-stress help for how to use.
- Compaction can now take into account overlapping tables that don't take part
in the compaction to look for deleted or overwritten data in the compacted tables.
Then such data is found, it can be safely discarded, which in turn should enable
the removal of tombstones over that data.
The behavior can be engaged in two ways:
- as a "nodetool garbagecollect -g CELL/ROW" operation, which applies
single-table compaction on all sstables to discard deleted data in one step.
- as a "provide_overlapping_tombstones:CELL/ROW/NONE" compaction strategy flag,
which uses overlapping tables as a source of deletions/overwrites during all
compactions.
The argument specifies the granularity at which deleted data is to be found:
- If ROW is specified, only whole deleted rows (or sets of rows) will be
discarded.
- If CELL is specified, any columns whose value is overwritten or deleted
will also be discarded.
- NONE (default) specifies the old behavior, overlapping tables are not used to
decide when to discard data.
Which option to use depends on your workload, both ROW and CELL increase the
disk load on compaction (especially with the size-tiered compaction strategy),
with CELL being more resource-intensive. Both should lead to better read
performance if deleting rows (resp. overwriting or deleting cells) is common.
- Prepared statements are now persisted in the table prepared_statements in
the system keyspace. Upon startup, this table is used to preload all
previously prepared statements - i.e. in many cases clients do not need to
re-prepare statements against restarted nodes.
- cqlsh can now connect to older Cassandra versions by downgrading the native
protocol version. Please note that this is currently not part of our release
testing and, as a consequence, it is not guaranteed to work in all cases.
See CASSANDRA-12150 for more details.
- Snapshots that are automatically taken before a table is dropped or truncated
will have a "dropped" or "truncated" prefix on their snapshot tag name.
- Metrics are exposed for successful and failed authentication attempts.
These can be located using the object names org.apache.cassandra.metrics:type=Client,name=AuthSuccess
and org.apache.cassandra.metrics:type=Client,name=AuthFailure respectively.
- Add support to "unset" JSON fields in prepared statements by specifying DEFAULT UNSET.
See CASSANDRA-11424 for details
- Allow TTL with null value on insert and update. It will be treated as equivalent to inserting a 0.
- Removed outboundBindAny configuration property. See CASSANDRA-12673 for details.
Upgrading
---------
- Support for alter types of already defined tables and of UDTs fields has been disabled.
If it is necessary to return a different type, please use casting instead. See
CASSANDRA-12443 for more details.
- Specifying the default_time_to_live option when creating or altering a
materialized view was erroneously accepted (and ignored). It is now
properly rejected.
- Only Java and JavaScript are now supported UDF languages.
The sandbox in 3.0 already prevented the use of script languages except Java
and JavaScript.
- Compaction now correctly drops sstables out of CompactionTask when there
isn't enough disk space to perform the full compaction. This should reduce
pending compaction tasks on systems with little remaining disk space.
- Request timeouts in cassandra.yaml (read_request_timeout_in_ms, etc) now apply to the
"full" request time on the coordinator. Previously, they only covered the time from
when the coordinator sent a message to a replica until the time that the replica
responded. Additionally, the previous behavior was to reset the timeout when performing
a read repair, making a second read to fix a short read, and when subranges were read
as part of a range scan or secondary index query. In 3.10 and higher, the timeout
is no longer reset for these "subqueries". The entire request must complete within
the specified timeout. As a consequence, your timeouts may need to be adjusted
to account for this. See CASSANDRA-12256 for more details.
- Logs written to stdout are now consistent with logs written to files.
Time is now local (it was UTC on the console and local in files). Date, thread, file
and line info where added to stdout. (see CASSANDRA-12004)
- The 'clientutil' jar, which has been somewhat broken on the 3.x branch, is not longer provided.
The features provided by that jar are provided by any good java driver and we advise relying on drivers rather on
that jar, but if you need that jar for backward compatiblity until you do so, you should use the version provided
on previous Cassandra branch, like the 3.0 branch (by design, the functionality provided by that jar are stable
accross versions so using the 3.0 jar for a client connecting to 3.x should work without issues).
- (Tools development) DatabaseDescriptor no longer implicitly startups components/services like
commit log replay. This may break existing 3rd party tools and clients. In order to startup
a standalone tool or client application, use the DatabaseDescriptor.toolInitialization() or
DatabaseDescriptor.clientInitialization() methods. Tool initialization sets up partitioner,
snitch, encryption context. Client initialization just applies the configuration but does not
setup anything. Instead of using Config.setClientMode() or Config.isClientMode(), which are
deprecated now, use one of the appropiate new methods in DatabaseDescriptor.
- Application layer keep-alives were added to the streaming protocol to prevent idle incoming connections from
timing out and failing the stream session (CASSANDRA-11839). This effectively deprecates the streaming_socket_timeout_in_ms
property in favor of streaming_keep_alive_period_in_secs. See cassandra.yaml for more details about this property.
- Duration litterals support the ISO 8601 format. By consequence, identifiers matching that format
(e.g P2Y or P1MT6H) will not be supported anymore (CASSANDRA-11873).
3.8
===
New features
------------
- Shared pool threads are now named according to the stage they are executing
tasks for. Thread names mentioned in traced queries change accordingly.
- A new option has been added to cassandra-stress "-rate fixed={number}/s"
that forces a scheduled rate of operations/sec over time. Using this, stress can
accurately account for coordinated ommission from the stress process.
- The cassandra-stress "-rate limit=" option has been renamed to "-rate throttle="
- hdr histograms have been added to stress runs, it's output can be saved to disk using:
"-log hdrfile=" option. This histogram includes response/service/wait times when used with the
fixed or throttle rate options. The histogram file can be plotted on
http://hdrhistogram.github.io/HdrHistogram/plotFiles.html
- TimeWindowCompactionStrategy has been added. This has proven to be a better approach
to time series compaction and new tables should use this instead of DTCS. See
CASSANDRA-9666 for details.
- Change-Data-Capture is now available. See cassandra.yaml and for cdc-specific flags and
a brief explanation of on-disk locations for archived data in CommitLog form. This can
be enabled via ALTER TABLE ... WITH cdc=true.
Upon flush, CommitLogSegments containing data for CDC-enabled tables are moved to
the data/cdc_raw directory until removed by the user and writes to CDC-enabled tables
will be rejected with a WriteTimeoutException once cdc_total_space_in_mb is reached
between unflushed CommitLogSegments and cdc_raw.
NOTE: CDC is disabled by default in the .yaml file. Do not enable CDC on a mixed-version
cluster as it will lead to exceptions which can interrupt traffic. Once all nodes
have been upgraded to 3.8 it is safe to enable this feature and restart the cluster.
Upgrading
---------
- The ReversedType behaviour has been corrected for clustering columns of
BYTES type containing empty value. Scrub should be run on the existing
SSTables containing a descending clustering column of BYTES type to correct
their ordering. See CASSANDRA-12127 for more details.
- Ec2MultiRegionSnitch will no longer automatically set broadcast_rpc_address
to the public instance IP if this property is defined on cassandra.yaml.
- The name "json" and "distinct" are not valid anymore a user-defined function
names (they are still valid as column name however). In the unlikely case where
you had defined functions with such names, you will need to recreate
those under a different name, change your code to use the new names and
drop the old versions, and this _before_ upgrade (see CASSANDRA-10783 for more
details).
Deprecation
-----------
- DateTieredCompactionStrategy has been deprecated - new tables should use
TimeWindowCompactionStrategy. Note that migrating an existing DTCS-table to TWCS might
cause increased compaction load for a while after the migration so make sure you run
tests before migrating. Read CASSANDRA-9666 for background on this.
3.7
===
Upgrading
---------
- A maximum size for SSTables values has been introduced, to prevent out of memory
exceptions when reading corrupt SSTables. This maximum size can be set via
max_value_size_in_mb in cassandra.yaml. The default is 256MB, which matches the default
value of native_transport_max_frame_size_in_mb. SSTables will be considered corrupt if
they contain values whose size exceeds this limit. See CASSANDRA-9530 for more details.
3.6
=====
New features