Release Notes for MongoDB 3.2
On this page
- Patch Releases
- WiredTiger as Default
- Replication Election Enhancements
- Sharded Cluster Enhancements
readConcern
- Partial Indexes
- Document Validation
- Aggregation Pipeline Enhancements
- MongoDB Tools Enhancements
- Encrypted Storage Engine
- Text Search Enhancements
- New Storage Engines
- General Enhancements
- Changes Affecting Compatibility
- Upgrade Process
- Known Issues in 3.2.1
- Known Issues in 3.2.0
- Download
Dec 8, 2015
MongoDB 3.2 is now available. Key features include WiredTiger as the
default storage engine, replication election enhancements, config
servers as replica sets, readConcern
, and document validations.
OpsManager 2.0 is also available. See the Ops Manager documentation and the Ops Manager release notes for more information.
Patch Releases
3.2.22 - Dec 28, 2018
SERVER-38425 Oplog Visibility Query is a collection scan in 3.2.21
3.2.21 - Sep 7, 2018
SERVER-32999: Platform Support: remove Debian 7.
SERVER-36010 Change log messages for Windows stacktraces to use error() or severe() rather than log().
SERVER-30724 Initial sync might miss ops that were in flight when it started.
3.2.20 - May 10, 2018
SERVER-32241: applyOps reports success even when a nested applyOps fails.
SERVER-32923: Platform Support: remove SLES11 builds.
SERVER-31535: Platform Support: remove Ubuntu 12.04 builds.
3.2.19 - Feb 6, 2018
SERVER-30189: Reduce calls to allocator for large $in expressions
SERVER-30853: Update Mongod init scripts to set unlimited locked memory
SERVER-32001: Unindexing a key in a partial unique index may cause server crash
SERVER-32048: Updates using a numeric path component may cause index entries not to be created
3.2.18 - Nov 29, 2017
SERVER-29287: Upgrade pcre to 8.41
SERVER-31101: WT table not dropped after collection is dropped due to long-running OperationContext
SERVER-31149: Enable recovery progress messages
3.2.17 - Sept 28, 2017
Issues fixed:
SERVER-30636: RangeDeleter assert failed because of replication lag
SERVER-30943: Segmentation fault on attempt to access an invalidated BSON Object in JS scope
WT-3327: Checkpoints can hang if time runs backward
3.2.16 - Jul 27, 2017
Issues fixed:
SERVER-26952: Cache SCRAM-SHA-1 ClientKey
SERVER-28578: When doing an upgrade from PV0 to PV1, we should not return from the reconfigure until the lastVote document is written.
SERVER-29568: Enable configuration of OpenSSL cipher suite via setParameter
3.2.15 - Jul 5, 2017
Issues fixed:
SERVER-29237: Add ShardingTaskExecutorPoolMaxConnecting flag for
mongos
.SERVER-29850: Access violation due to a bug in internal page splitting in WiredTiger.
WT-3362: Cursor opens should never block for the duration of a checkpoint.
3.2.14 -Jun 13, 2017
Issues fixed:
SERVER-26452:
renameCollection
should handle write conflicts.SERVER-29365: No-op
applyOps
does not wait for majority writeConcern before returning.SERVER-28014: When ssl mode is
preferSSL
, should log connections that do not use SSL.
3.2.13 -- May 1, 2017
Issues fixed:
SERVER-3181: Add
nameOnly
option to listDatabases to only get db names, not size info.SERVER-21818: Capture system metrics in FTDC
SERVER-25318: Limit total memory utilization for bulk index builds
3.2.12 -- Feb 1, 2017
Issues fixed:
SERVER-27125 Arbiters in
pv1
should vote no in elections if they can see a healthy primary of equal or greater priority to the candidate.SERVER-25012:
createIndex
blocks for duration of checkpoint while holding locks.SERVER-25865:
$group
operation is slow on Windows.
3.2.11 -- Nov 18, 2016
Issues fixed:
SERVER-26182: In a mixed version replica set with v3.2 and v3.0 members, a sync of a v3.2 member from a v3.0 member can result in a query response that exceed 16 MB BSON size limit and crash the v3.2 member.
SERVER-24662: Upgrade to Perl compatible regular expressions (PCRE 8.39).
SERVER-26652 Invalid definitions in
systemd
configuration for Debian.SERVER-24386:
killCursor
operation during aggregation pipeline can cause segmentation fault.
3.2.10 -- Sep 30, 2016
Issues fixed:
SERVER-25974: When WT cache utilization is full, application threads can stall for an extended period of time.
SERVER-20306: MongoDB with WiredTiger may experience excessive memory fragmentation, leading to swapping and/or out-of-memory errors.
SERVER-16801: When updating a field of one numerical type to the same number of different numerical type, update operation considers it as a noop.
3.2.9 -- Aug 16, 2016
Issues fixed:
SERVER-7285: Support systemd in future compatible Ubuntu distributions.
WT-2798: Create operations on WiredTiger when journaling is disabled may lead to inconsistent data in the event of a crash.
SERVER-17856: On
mongod
instances, users can runcurrentOp
andkillOp
on own operations.
3.2.8 -- Jul 12, 2016
Issues fixed:
SERVER-18329: Debian 8(Jessie) packages.
SERVER-24580: Improve performance when WiredTiger cache is full.
WT-2696: Race condition on unclean shutdown may miss log records with large updates.
WT-2706: Race condition on log file switch can cause missing log records.
3.2.7 -- Jun 7, 2016
Issues fixed:
SERVER-24054: JS segmentation fault on load of certain NaNs.
SERVER-24058: Connection pool asio doesn't honor setup timeouts.
SERVER-24117: Mongo binaries ELF stack has become executable.
3.2.6 -- Apr 28, 2016
First production release of the in-memory storage engine.
Issues fixed:
SERVER-22970: Background index build may result in extra index key entries that do not correspond to indexed documents.
SERVER-22043:
mongo
shell methodcount()
ignores read preference.
3.2.5 -- Apr 14, 2016
Issues fixed:
SERVER-22964: IX GlobalLock held while waiting for WiredTiger cache eviction.
SERVER-22831: Low query rate with heavy cache pressure and an idle collection.
SERVER-21681: Include index size stats for in-memory storage engine.
3.2.4 -- Mar 8, 2016
Issues fixed:
SERVER-22495, SERVER-22728: Update optime when running with journaling disabled.
SERVER-22269: Have read concern
majority
reflect journaled state on the primarySERVER-22683:
replication.enableMajorityReadConcern
ignores actual setting value and instead impliestrue
.SERVER-22043:
count()
method in themongo
shell does not apply the read preferences.
3.2.3 -- Feb 17, 2016
Issues fixed:
SERVER-22261: For MMAPv1 journaling, the "last sequence number" file (
lsn
file) may be ahead of what is synced to the data files.SERVER-22167: In some cases, insert operations fails to add the
_id
field to large documents.SERVER-22456: Increased timeout for querying oplog to 1 minute.
3.2.2 -- Feb 16, 2016
Replaced by MongoDB 3.2.3. Users wishing to run MongoDB 3.2 should skip 3.2.2 and upgrade directly to 3.2.3.
3.2.1 -- Jan 12, 2016
Issues fixed:
SERVER-21868: During a regular shutdown of a replica set, secondaries may mark certain replicated but yet to be applied operations as successfully applied.
SERVER-20262: Improve insert workload performance with WiredTiger on Windows.
SERVER-21366: Long-running transactions during chunk moves.
WiredTiger as Default
Starting in 3.2, MongoDB uses the WiredTiger as the default storage engine.
To specify the MMAPv1 storage engine, you must specify the storage engine setting either:
On the command line with the
--storageEngine
option:mongod --storageEngine mmapv1 Or in a Configuration File, using the
storage.engine
setting:storage: engine: mmapv1
Note
For existing deployments, if you do not specify the
--storageEngine
or the storage.engine
setting,
MongoDB 3.2 can automatically determine the storage engine
used to create the data files in the --dbpath
or
storage.dbPath
.
If specifying --storageEngine
or storage.engine
,
mongod
will not start if dbPath
contains data files
created by a storage engine other than the one specified.
WiredTiger Default Cache Size
Starting in MongoDB 3.2, the WiredTiger internal cache, by default, will use the larger of either:
60% of RAM minus 1 GB, or
1 GB.
For more information, see WiredTiger and Memory Use.
WiredTiger Journal Write Frequency
MongoDB 3.2 configures WiredTiger to write to the journal files at every 50 milliseconds. This is in addition to the existing journal write intervals and conditions. For more information, see Journaling Process.
Replication Election Enhancements
Starting in MongoDB 3.2, MongoDB reduces replica set failover time and accelerates the detection of multiple simultaneous primaries.
As part of this enhancement, MongoDB introduces a version 1 of the
replication protocol. New replica sets will, by default, use
protocolVersion: 1
. Previous versions of
MongoDB use version 0 of the protocol.
In addition, MongoDB introduces a new replica set configuration option
electionTimeoutMillis
.
electionTimeoutMillis
specifies the time limit in
milliseconds for detecting when a replica set's primary is unreachable.
electionTimeoutMillis
only applies if using the
version 1 of the replication protocol
.
Sharded Cluster Enhancements
MongoDB 3.2 deprecates the use of three mirrored mongod
instances for config servers.
Instead, starting in 3.2, the config servers for a sharded cluster can be deployed as a replica set. The replica set config servers must run the WiredTiger storage engine.
This change improves consistency across the config servers, since MongoDB can take advantage of the standard replica set read and write protocols for sharding config data. In addition, this allows a sharded cluster to have more than 3 config servers since a replica set can have up to 50 members.
For more information, see Config Servers. To deploy a new sharded cluster with replica set config servers, see Deploy a Sharded Cluster.
MongoDB 3.2 deprecates the use of master-slave replication for components of sharded clusters.
Starting in 3.2, mongos
, during its startup, will continue
to try to contact the config servers until one becomes available. In
previous versions, mongos
, during its startup, would shut
down if it could not find a config server.
readConcern
MongoDB 3.2 introduces the readConcern
query option for replica sets and replica
set shards. For the WiredTiger storage engine, the readConcern
option allows clients to
choose a level of isolation for their reads. You can specify a
readConcern
of "majority"
to read data that has been written to
a majority of nodes and thus cannot be rolled back. By default, MongoDB
uses a readConcern
of "local"
to return the most recent data
available to the node at the time of the query, even if the data has
not been persisted to a majority of nodes and may be rolled back. With
the MMAPv1 storage engine, you can only specify a
readConcern
of "local"
.
readConcern
requires MongoDB drivers updated for MongoDB 3.2.
For details on readConcern
, including operations that support the
option, see Read Concern.
Partial Indexes
MongoDB 3.2 provides the option to create indexes that only index
the documents in a collection that meet a specified filter expression.
By indexing a subset of the documents in a collection, partial indexes
have lower storage requirements and reduced performance costs for index
creation and maintenance. You can specify a partialFilterExpression
option for all MongoDB index types.
The partialFilterExpression
option accepts a document that specifies the
condition using:
equality expressions (i.e.
field: value
or using the$eq
operator),$exists: true
expression,$type
expressions,$and
operator at the top-level only
For details, see Partial Indexes.
Document Validation
Starting in 3.2, MongoDB provides the capability to validate documents during updates and insertions. Validation rules are specified on a per-collection basis.
To specify document validation on a new collection, use the new
validator
option in the db.createCollection()
method. To
add document validation to an existing collection, use the new
validator
option in the collMod
command. For more
information, see Schema Validation.
To view the validation specifications for a collection, use the
db.getCollectionInfos()
method.
The following commands can bypass validation per operation using the
new option bypassDocumentValidation
:
applyOps
commandfindAndModify
command anddb.collection.findAndModify()
methodmapReduce
command anddb.collection.mapReduce()
methodinsert
commandupdate
command$out
for theaggregate
command anddb.collection.aggregate()
method
For deployments that have enabled access control, you must have
bypassDocumentValidation
action. The built-in roles
dbAdmin
and restore
provide this action.
Aggregation Pipeline Enhancements
MongoDB introduces:
New stages, accumulators, and expressions.
Performance improvements on sharded clusters.
New Aggregation Stages
Stage | Description | Syntax | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Randomly selects N documents from its input. | { $sample: { size: <positive integer> } } | ||||||||||
Returns statistics on index usage. | { $indexStats: { } } | ||||||||||
Performs a left outer join with another collection. |
|
New Accumulators for $group
Stage
Accumulator | Description | Syntax |
---|---|---|
Calculates standard deviation. | { $stdDevSamp: <array> } | |
Calculates population standard deviation. | { $stdDevPop: <array> } |
New Aggregation Arithmetic Operators
Operator | Description | Syntax |
---|---|---|
Calculates the square root. | { $sqrt: <number> } | |
Returns the absolute value of a number. | { $abs: <number> } | |
Calculates the log of a number in the specified base. | { $log: [ <number>, <base> ] } | |
Calculates the log base 10 of a number. | { $log10: <number> } | |
Calculates the natural log of a number. | { $ln: <number> } | |
Raises a number to the specified exponent. | { $pow: [ <number>, <exponent> ] } | |
Raises e to the specified exponent. | { exp: <number> } | |
Truncates a number to its integer. | { $trunc: <number> } | |
Returns the smallest integer greater than or equal to the
specified number. | { $ceil: <number> } | |
Returns the largest integer less than or equal to the specified
number. | { floor: <number> } |
New Aggregation Array Operators
Operator | Description | Syntax | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Returns a subset of an array. |
or
| |||||||||
Returns the element at the specified array index. | { $arrayElemAt: [ <array>, <idx> ] } | |||||||||
Concatenates arrays. |
| |||||||||
Determines if the operand is an array. | { $isArray: [ <expression> ] } | |||||||||
Selects a subset of the array based on the condition. |
|
Accumulator Expression Availability
Starting in version 3.2, the following accumulator expressions,
previously only available in the $group
stage, are now also
available in the $project
stage:
When used as part of the $project
stage, these accumulator
expressions can accept either:
A single argument:
<accumulator> : <arg>
Multiple arguments:
<accumulator> : [ <arg1>, <arg2>, ... ]
General Enhancements
In MongoDB 3.2,
$project
stage supports using the square brackets[]
to directly create new array fields. For an example, see Project New Array Fields.MongoDB 3.2 introduces the
minDistance
option for the$geoNear
stage.$unwind
stage no longer errors on non-array operand. If the operand does not resolve to an array but is not missing, null, or an empty array,$unwind
treats the operand as a single element array.$unwind
stage can:include the array index of the array element in the output by specifying a new option
includeArrayIndex
in the stage specification.output those documents where the array field is missing, null or an empty array by specifying a new option
preserveNullAndEmptyArrays
in the stage specification.
To support these new features,
$unwind
can now take an alternate syntax. See$unwind
for details.
Optimization
Indexes can cover aggregation operations.
MongoDB improves the overall performance of the pipeline in large sharded clusters.
If the pipeline starts with an exact $match
on a shard key,
the entire pipeline runs on the matching shard only. Previously, the
pipeline would have been split, and the work of merging it would have
to be done on the primary shard.
For aggregation operations that run on multiple shards, if the
operations do not require running on the database's primary shard,
these operations can route the results to any shard to merge the
results and avoid overloading the primary shard for that database.
Aggregation operations that require running on the database's primary
shard are the $out
stage and $lookup
stage.
Compatibility
For compatibility changes, see Aggregation Compatibility Changes.
MongoDB Tools Enhancements
mongodump
andmongorestore
add support for archive files and standard output/input streams with a new--archive
option. This enhancement allows for the streaming of the dump data over a network device via a pipe. For examples, seemongodump
andmongorestore
add support for compressed data dumps with a new--gzip
option. This enhancement reduces storage space for the dump files. For examples, see:
Encrypted Storage Engine
Note
Enterprise Feature
Available in MongoDB Enterprise only.
Important
Available for the WiredTiger Storage Engine only.
Encryption at rest, when used in conjunction with transport encryption and good security policies that protect relevant accounts, passwords, and encryption keys, can help ensure compliance with security and privacy standards, including HIPAA, PCI-DSS, and FERPA.
MongoDB Enterprise 3.2 introduces a native encryption option for the WiredTiger storage engine. This feature allows MongoDB to encrypt data files such that only parties with the decryption key can decode and read the data. For detail, see Encrypted Storage Engine.
Text Search Enhancements
text
Index Version 3
MongoDB 3.2 introduces a version 3 of the text index. Key features of the new version of the index are:
Improved case insensitivity.
Additional delimiters for tokenization.
Starting in MongoDB 3.2, version 3 is the default version for new text indexes.
$text
Operator Enhancements
The $text
operator adds support for:
case sensitive text search with the new
$caseSensitive
option, anddiacritic sensitive text search with the new
$diacriticSensitive
option.
For more information and examples, see the $text
operator
reference sections Case Insensitivity and
Diacritic Insensitivity.
Support for Additional Languages
Note
Enterprise Feature
Available in MongoDB Enterprise only.
Starting in 3.2, MongoDB Enterprise provides support for the following languages: Arabic, Farsi (specifically Dari and Iranian Persian dialects), Urdu, Simplified Chinese, and Traditional Chinese.
For details, see Text Search with Basis Technology Rosette Linguistics Platform.
New Storage Engines
inMemory
Storage Engine
Note
Enterprise Feature
Available in MongoDB Enterprise only.
MongoDB Enterprise 3.2 provides an in-memory storage engine. Other than some metadata, the in-memory storage engine does not maintain any on-disk data. By avoiding disk I/O, the in-memory storage engine allows for more predictable latency of database operations.
To select this storage engine, specify
inMemory
for the--storageEngine
option or thestorage.engine
setting.--dbpath
. Although the in-memory storage engine does not write data to the filesystem, it maintains in the--dbpath
small metadata files and diagnostic data as well temporary files for building large indexes.
The inMemory
storage engine uses document-level locking. For more details,
see In-Memory Storage Engine.
ephemeralForTest
Storage Engine
MongoDB 3.2 provides a new for-test storage engine. Other than some metadata, the for-test storage engine does not maintain any on-disk data, removing the need to clean up between test runs. The for-test storage engine is unsupported.
Warning
For test purposes only. Do not use in production.
To select this storage engine, specify
ephemeralForTest
for the--storageEngine
option or thestorage.engine
setting.--dbpath
. Although the for-test storage engine does not write data to the filesystem, it maintains small metadata files in the--dbpath
.
The ephemeralForTest
storage engine uses collection-level locking.
General Enhancements
Bit Test Query Operators
MongoDB 3.2 provides new query operators to test bit values:
SpiderMonkey JavaScript Engine
MongoDB 3.2 uses SpiderMonkey as the JavaScript engine for the
mongo
shell and mongod
server. SpiderMonkey
provides support for additional platforms and has an improved memory
management model.
This change affects all JavaScript behavior including the commands
mapReduce
, group, and the query operator
$where
; however, this change should be completely
transparent to the user.
mongo
Shell and CRUD API
To provide consistency with the MongoDB drivers' CRUD
(Create/Read/Update/Delete) API, the mongo
shell introduces
additional CRUD methods that are consistent with the drivers' CRUD API:
New API | Description |
---|---|
Equivalent to initializing | |
Equivalent to db.collection.remove() . | |
Equivalent to
| |
Equivalent to db.collection.findAndModify() method
with remove set to true. | |
Equivalent to db.collection.findAndModify() method
with update set to a replacement document. | |
Equivalent to db.collection.findAndModify() method
with update set to a document that specifies modifications
using update operators. | |
Equivalent to db.collection.insert() method
with an array of documents as the parameter. | |
Equivalent to db.collection.insert() method
with a single document as the parameter. | |
Equivalent to db.collection.update( <query>,
<update> ) method with a replacement
document as the <update> parameter. | |
Equivalent to db.collection.update( <query>,
<update>, { multi: true, ... })
method with an <update> document that specifies
modifications using update operators and the multi option set to
true. | |
Equivalent to db.collection.update( <query>,
<update> ) method with an
<update> document that specifies modifications using
update operators. |
WiredTiger and fsyncLock
Starting in MongoDB 3.2, the WiredTiger storage engine supports the
fsync
command with the lock
option or the
mongo
shell method db.fsyncLock()
. That is, for
the WiredTiger storage engine, these operations can guarantee that the
data files do not change, ensuring consistency for the purposes of
creating backups.
Platform Support
Starting in 3.2, 32-bit binaries are deprecated and will be unavailable in future releases.
MongoDB 3.2 also deprecates support for Red Hat Enterprise Linux 5.
$type
Operator Accepts String Aliases
$type
operator accepts string aliases for the BSON types in
addition to the numbers corresponding to the BSON types.
explain()
Support for distinct()
Operation
db.collection.explain()
adds support for
db.collection.distinct()
method. For more information, see
db.collection.explain()
.
explain
Support for findAndModify
and distinct
Commands
explain
adds support for the distinct
and
findAndModify
commands. For more information, see
explain
.
Deprecation of the HTTP Interface
Starting in 3.2, MongoDB deprecates its HTTP interface.
keysExamined
Count Includes the Last Scanned Key
For explain
operations run in executionStats
or
allPlansExecution
mode, the explain output contains the keysExamined
statistic,
representing the number of index keys examined during index scans.
Prior to 3.2, keysExamined
count in some queries did not include the
last scanned key. As of 3.2 this error has been corrected. For more
information, see
inputStage
.
The diagnostic logs and the system profiler report on this statistic.
Geospatial Optimization
MongoDB 3.2 introduces version 3 of 2dsphere Indexes, which index
GeoJSON geometries at a finer gradation. The
new version improves performance of 2dsphere
index queries over
smaller regions. In addition, for both 2d Indexes and 2dsphere
indexes, the performance of geoNear queries has been improved for dense
datasets.
Diagnostic Data Capture
To facilitate analysis of the MongoDB server behavior by MongoDB
engineers, MongoDB 3.2 introduces a diagnostic data collection
mechanism for logging server statistics to diagnostic files at periodic
intervals. By default, the mechanism captures data at 1 second
intervals. To modify the interval, see
diagnosticDataCollectionPeriodMillis
.
MongoDB creates a diagnostic.data
directory under the
mongod
instance's --dbpath
or storage.dbPath
.
The diagnostic data is stored in files under this directory.
The maximum size of the diagnostic files is configurable with the
diagnosticDataCollectionFileSizeMB
, and the maximum size
of the diagnostic.data
directory is configurable with
diagnosticDataCollectionDirectorySizeMB
.
The default values for the capture interval and the maximum sizes are chosen to provide useful data to MongoDB engineers with minimal impact on performance and storage size. Typically, these values will only need modifications as requested by MongoDB engineers for specific diagnostic purposes.
Write Concern
For replica sets using
protocolVersion: 1
, secondaries acknowledge write operations after the secondary members have written to their respective on-disk journals, regardless of the j option.For replica sets using
protocolVersion: 1
,w: "majority"
implies j: true.With
j: true
, MongoDB returns only after the requested number of members, including the primary, have written to the journal. Previouslyj: true
write concern in a replica set only requires the primary to write to the journal, regardless of the w: <value> write concern.
journalCommitInterval
for WiredTiger
MongoDB 3.2 adds support for specifying the journal commit interval for
the WiredTiger storage engine. See --journalCommitInterval
option. In previous versions, the option is applicable to MMAPv1
storage engine only.
For the corresponding configuration file setting, MongoDB 3.2 adds the storage.journal.commitIntervalMs setting and deprecates storage.mmapv1.journal.commitIntervalMs. The deprecated storage.mmapv1.journal.commitIntervalMs setting acts as an alias to the new storage.journal.commitIntervalMs setting.
Changes Affecting Compatibility
Some MongoDB 3.2 changes can affect compatibility and may require user actions. For a detailed list of compatibility changes, see Compatibility Changes in MongoDB 3.2.
Upgrade Process
See Upgrade MongoDB to 3.2 for full upgrade instructions.
Known Issues in 3.2.1
List of known issues in the 3.2.1 release:
Clients may fail to discover new primaries when clock skew between nodes is greater than
electionTimeout
: SERVER-21744fromMigrate
flag never set for deletes in oplog: SERVER-21678Running
explain
with a read preference in a v3.2mongo
shell connected to a v3.0mongos
or in a v3.0mongo
shell connected to a v3.0mongos
but with v3.2 shards is incompatible: SERVER-21661Results of the connPoolStats command are no longer correct: SERVER-21597
ApplyOps background index creation may deadlock: SERVER-21583
Performance regression for
w:majority
writes with replica set protocolVersion 1: SERVER-21581Performance regression on unicode-aware text processing logic (text index v3): SERVER-19936
Results from the
$indexStats
operator do not take into account queries which use the$match
ormapReduce
functions: SERVER-22048
Known Issues in 3.2.0
List of known issues in the 3.2.0 release:
findAndModify operations not captured by the profiler: SERVER-21772
getMore
command does not set"nreturned"
operation counter: SERVER-21750Clients may fail to discover new primaries when clock skew between nodes is greater than
electionTimeout
: SERVER-21744fromMigrate
flag never set for deletes in oplog: SERVER-21678Running
explain
with a read preference in a v3.2mongo
shell connected to a v3.0mongos
or in a v3.0mongo
shell connected to a v3.0mongos
but with v3.2 shards is incompatible: SERVER-21661Results of the connPoolStats command are no longer correct: SERVER-21597
ApplyOps background index creation may deadlock: SERVER-21583
Performance regression for
w:majority
writes with replica set protocolVersion 1: SERVER-21581Performance regression on unicode-aware text processing logic (text index v3): SERVER-19936
Severe performance regression in insert workload under Windows with WiredTiger: SERVER-21792
Results from the
$indexStats
operator do not take into account queries which use the$match
ormapReduce
functions: SERVER-22048
Download
To download MongoDB 3.2, go to the downloads page.