資料結構一直改，MongoDB 能幫上什麼忙

What's new in this version:

Security:
- Remove size limits on BSON audit events
- Improve deterministic calculation of key container names
- mongod cannot verify certificates from the CNG provider

Sharding:
- sh.status() “Last reported error:” is actually 5th Latest error message
- Parts of the _configsvrShardCollection command do not retry on network errors
- MigrationSourceManager is not exception safe before startClone completes
- Ignore duplicate key error from refreshLogicalSessionCacheNow
- Optimize splitVector for the jumbo-chunk case
- agg_out.js concurrency workload always fails to shard the output collection
- failcommand_ignores_internal.js fails against mongod 3.6
- Migrating session info can trigger fassert when destination shard has transaction history truncated by oplog
- Shard secondaries with 4.0 binary and 3.6 FCV are calling _flushDatabaseCacheUpdates

Replication:
- Replication recovery does not update the logical clock
- Wait for specified write concern whenever commitTransaction returns a NoSuchTransaction error
- commands_that_accept_wc tests can give secondaries priority zero
- prohibit MapReduce on sessions with txnNumbers
- writeConcern can be satisfied with an arbiter if the write was committed
- Killing session on a secondary currently applying prepare oplog entry can fassert
- Allow shutdown error when reading last applied optime on startup
- CollectionCloner should handle QueryPlanKilled on collection drop
- Fix aggregation_currentop.js such that we don’t compare timestamps generated from 2 different sources (mozjs & server).
- server_write_concern_metrics.js must use requires_journaling tag
- opWriteConcernCounters can cause undefined behavior due to overflow
- Blacklist max_time_ms.js from read concern linearizable passthrough

Query:
- Allow $not to be applied to $regex (currently only /regex/ syntax is allowed)
- Reduce severity or remove log message for PlanExecutor::DEAD error during find
- External sorter should use 64-bit integers for file offsets
- Add debug logging to change_streams/shell_helper.js
- Backport changes to apply_ops_concurrent_non_atomic.js to account for HMAC key inserts in 3.6 and 4.0.
- Ensure internal options cannot be specified in a raw aggregate command sent to mongos
- TextMatchExpression crashes instead of serializing in some cases

Aggregation:
- Wrong ns in system.profile for aggregation query
- Report high-water-mark resume token with each (possibly empty) change stream batch
- Return postBatchResumeToken from all mongoD change streams
- Allow ARM to consume postBatchResumeToken for merging
- Propagate postBatchResumeToken through mongoS to client
- Allow resuming from a high-water-mark resume token
- Always set an initial postBatchResumeToken
- Upgrade/Downgrade testing for change stream high water mark
- Improve robustness of postBatchResumeToken integration tests
- Single-collection high water marks omit UUID on shards where the collection does not exist
- $graphLookup should force a pipeline to split in sharded cluster
- Backport timelib fix for incorrect snprintf invocation with static buffer
- Views collation check should traverse through nested $lookup pipelines
- Re-enable batching in DSCursor for change stream cursors
- Aggregation operator $sqrt output for NumberDecimal is the same as $exp
- Validate fields in $geoNear
- Do not prematurely reject resume attempt in DSShardCheckResumability

JavaScript:
- Remove unused C++ injected JS constructors

Storage:
- Reduce file handle usage in File based Sorter
- Return the oldest read timestamp used by any open transaction
- Hyphenated database names do not work with dbStats.fsUsedSize / TotalSize
- cappedTruncateAfter must not set oldest timestamp during startup recovery when enableMajorityReadConcern=false
- MigrationDestinationManager assigns incorrect timestamps while building multiple indexes
- Cope with large BSON blobs in queryable’s listDirectory call.
- A failure to timestamp a storage transaction requires restarting the transaction
- GlobalLock acquisition should throw when ticket acquisition times out if there is a max lock timeout and no deadline
- Mobile SE: Adjust SQLite Pragmas for Improved Performance
- Ensure that a node performing an initial sync from a secondary with a in-progress index build creates the index before initial sync is done
- Change listIndexes command behavior to show in-progress index builds
- decrease number of updates in rollback_wt_cache_full.js
- Make catalog_raii_test more resistant to clock issues on Windows
- Fix lock stats suboperation tests for mobile

Operations:
- Expose metrics on idle versus active client threads
- Improve the LDAP server logging
- mongo shell should be linked with ErrorExtraInfo derivatives
- Add getResumeToken shell helper
- Cannot use TLS with readPreference={mode: “secondary”} without specifying –ssl to mongo shell

Build and Packaging:
- When using thin archives the –cache=nolinked mode should push thin archives to the cache
- Add release process builder for embedded SDKs
- install_compass fails on MacOS
- Remove SCons cache pruning from prior branches
- Stripped binaries and .debug files should not be cached

Tools:
- mongodump does not dump system.js collections
- Build Tools with Go 1.11
- mongoimport –uri logs incorrect connected hosts

Internals:
- service_state_machine.cpp should log a backtrace if there’s an uncaught exception
- Mongobridge nodes don’t remember their network partition configuration after a restart
- Mongos write path doesn’t look for retryable write concern errors
- BSONElement::safeNumberLong is not safe
- printShardingStatus.js races with ShardingUptimeReporter thread
- Improve watchdog_test reliability
- DBClientRS should propagate URI options through all paths
- Improve thread safety of PeriodicRunnerImpl
- –ssl=off builds emit a scons warning
- Powercycle kill by PID might try to kill the wrong process
- Maven central release automation cannot close sonatype repository (401 unauthorized)
- Provide reason for transaction abort
- Background indexes created through applyOps should run on the command thread
- Accept connection failure on Windows in ssl_alert_reporting.js
- Use generate.tasks for required tasks over target runtime
- Make periodic_runner_impl_test more lenient in OnePausableJobResumesCorrectly
- currentOp is not resilient to drop shard
- Increase query execution time for the test case in max_time_ms.js that expects it to hit the time limit
- Make bulldlogger credentials location configurable via environment variable
- Incorrect error reported while re-installing with the Windows MSI
- $elemMatch $ne serialization is incorrect, doesn’t roundtrip
- Make SCons default –jobs to CPU count
- Further refine readWriteAnyDatabase
- Synchronize user set modification in AuthorizationSession with Client
- Use generate.tasks for already converted tasks on all variants
- Avoid double-authentication during connect from mongo shell
- New test suites do not handle excludes properly when dividing suites
- waitForSecondaries in background dbhash check must wait for lastApplied to reach clusterTime when enableMajorityReadConcern=false
- Allow commands that do not require auth to refresh sessions
- Better handle timeouts for generated tasks with repeated execution
- Coverity analysis defect 105263: Dereference after null check
- Specifically use the version of the android NDK that we want to use
- Fix opCtx and baton waits
- burn_in_tests.py doesn’t run tests in the configuration for *_gen Evergreen tasks
- improve port_options.js logfile polling
- Clean up cloud_nightly project file
- System-Performance: Write project in runtime.yml
- Don’t override timeouts if not all test have history
- Improve watchdog_test.exe test reliability
- Free Monitoring may ignore re-register requests on secondaries
- Race in PeriodicRunnerImpl between start() and stop()
- change_streams_resume_at_same_clustertime.js should not assume same that multi-update across shards are performed at the same clusterTime
- Handle splitting tasks with only filtered test history
- Set setup_group_can_fail_task to true for compile-related task groups
- Tag JavaScript tests with the reason they’re unable to run in Atlas
- Pin all Gradle dependencies
- Ignore mongorestore error “x509 certificate routines:X509_STORE_add_cert:cert already in hash table”
- mongodump failing on Windows with “error opening system CA store: Access is denied.”
- Add CGO flags for building on Windows
- Add CGO flags for building on MacOS
- Build with tools with Address Space Layout Randomised (ASLR) flags enabled
- Add prototype implementation allowing limiting of IO per subsystem
- Improve caching of small updates to large values
- Give applications a chance to handle panic before API panic returns
- Update WiredTiger copyrights to 2019
- Retry Windows functions on access denied
- Fix null pointer access to WT_DATA_HANDLE in __wt_page_in_func
- Consolidate capacity and block manager bytes written
- Coverity: possible divide by zero conn_capacity:434
- Coverity warning in conn_capacity.c
- Sync backup file before returning backup cursor