Optimize Is (Not) Bad For You
Deep Dive Into The Segment Merge Abyss
Rafał Kuć
Sematext Group, Inc.
Agenda
• Segments – where, what & how
• Writing segments
• Modifying segments
• Segment merging – what, where, how, why
• Force merging
• Force merging & SolrCloud
• Performance considerations
• Specialized merge policies
https://github.com/sematext/lr/tree/master/2017/optimize
3
01
Sematext & I
cloud
metrics
logs
&
4
01
Solr Collection Architecture
Zookeeper
5
01
Solr Collection Architecture
Zookeeper
SOLR
SOLR
SOLR
SOLR
6
01
Solr Collection Architecture
Zookeeper
SOLR
shard shard
SOLR
shard shard
SOLR
shard shard
SOLR
shard shard
7
01
Solr Shard Architecture
TLOG
8
01
Solr Shard Architecture
TLOG
Segment Segment Segment
Segment
9
01
Lucene Segment
Segment Info
Field Names
Stored Field Values
Point Values
Term Dictionary
Term Frequency
Term Proximity
Normalization
Per Document Vals
Live Documents
1
01
Inside the Segment – Term Dictionary
TERM DOCID
lucene <1>, <2>
revolution <1>, <2>
washington <1>
boston <2>
_1.tim
Doc1 Title: Lucene Revolution Washington, City: Washington D.C
Doc2 Title: Lucene Revolution Boston, City: Boston
_1.tip
1
01
Inside the Segment – Doc Values
Doc1 Title: Lucene Revolution Washington, City: Washington D.C
Doc2 Title: Lucene Revolution Boston, City: Boston
DOCID FIELD VALUE
1 Title Lucene Revolution Washington
1 City Washington D.C.
2 Title Lucene Revolution Boston
2 City Boston
_1.dvd
_1.dvm
1
01
Inside the Segment – Stored Fields
Doc1 Title: Lucene Revolution Washington, City: Washington D.C
Doc2 Title: Lucene Revolution Boston, City: Boston
DOCID VALUE
1 Title: Lucene Revolution Washington
City: Washington D.C
2 Title: Lucene Revolution Boston
City: Boston
_1.fdx
_1.fdt
1
01
Inside the Segment – Compound File System
_1.fdt
_1.fdx
_1.fnm
_1.nvd
_1.nvm
_1.si
_1.Lucene50_0.doc
_1.Lucene50_0.pos
_1.Lucene50_0.tim
_1.Lucene50_0.tip
_1.Lucene50_0.dvd
_1.Lucene50_0.dvm
1
01
Inside the Segment – Compound File System
_1.fdt
_1.fdx
_1.fnm
_1.nvd
_1.nvm
_1.si
_1.Lucene50_0.doc
_1.Lucene50_0.pos
_1.Lucene50_0.tim
_1.Lucene50_0.tip
_1.Lucene50_0.dvd
_1.Lucene50_0.dvm
1
01
Inside the Segment – Compound File System
_1.fdt
_1.fdx
_1.fnm
_1.nvd
_1.nvm
_1.si
_1.Lucene50_0.doc
_1.Lucene50_0.pos
_1.Lucene50_0.tim
_1.Lucene50_0.tip
_1.Lucene50_0.dvd
_1.Lucene50_0.dvm
_2.cfs
_2.cfe
1
01
Indexing
1
01
Indexing
1
01
Indexing
1
01
Indexing
level/tier
2
01
Indexing
2
01
Indexing
2
01
Indexing
2
01
Indexing
2
01
Indexing
2
01
Indexing
2
01
Indexing
2
01
Deletes
2
01
Deletes – After Merge
2
01
Atomic Updates
$ curl -XPOST -H 'Content-Type: application/json'
'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[
{
"id" : "3",
"tags" : {
"add" : [ "solr" ]
}
}
]'
retrieve document
{
"id" : 3,
"tags" : [ "lucene" ],
"awesome" : true
}
3
01
Atomic Updates
$ curl -XPOST -H 'Content-Type: application/json'
'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[
{
"id" : "3",
"tags" : {
"add" : [ "solr" ]
}
}
]'
{
"id" : 3,
"tags" : [ "lucene", "solr" ],
"awesome" : true
}
apply changes
3
01
Atomic Updates
$ curl -XPOST -H 'Content-Type: application/json'
'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[
{
"id" : "3",
"tags" : {
"add" : [ "solr" ]
}
}
]'
{
"id" : 3,
"tags" : [ "lucene", "solr" ],
"awesome" : true
}
delete old document
3
01
Atomic Updates
$ curl -XPOST -H 'Content-Type: application/json'
'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[
{
"id" : "3",
"tags" : {
"add" : [ "solr" ]
}
}
]'
{
"id" : 3,
"tags" : [ "lucene", "solr" ],
"awesome" : true
}
3
01
Atomic Updates – In Place
Works on top of numeric, doc values based fields
Fields need to be not indexed and not stored
Doesn’t require delete/index
Support only inc and set modifers
$ curl -XPOST -H 'Content-Type: application/json'
'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[
{
"id" : "3",
"views" : {
"inc" : 100
}
}
]'
3
01
Atomic Updates – In Place
$ curl -XPOST -H 'Content-Type: application/json'
'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[
{
"id" : "3",
"views" : {
"inc" : 100
}
}
]'
retrieve document
{
"id" : 3,
"tags" : [ "lucene", "solr" ],
"awesome" : true
}
3
01
Atomic Updates – In Place
$ curl -XPOST -H 'Content-Type: application/json'
'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[
{
"id" : "3",
"views" : {
"inc" : 100
}
}
]'
{
"id" : 3,
"tags" : [ "lucene", "solr" ],
"awesome" : true,
"views" : 100
}
apply changes
3
01
Atomic Updates – In Place
$ curl -XPOST -H 'Content-Type: application/json'
'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[
{
"id" : "3",
"views" : {
"inc" : 100
}
}
]'
{
"id" : 3,
"tags" : [ "lucene", "solr" ],
"awesome" : true,
"views" : 100
}
update doc values
3
01
Search – Importance of Segments
Immutable – write once read many
3
01
Search – Importance of Segments
Immutable – write once read many
More segments – slower search speed
3
01
Search – Importance of Segments
Immutable – write once read many
More segments – slower search speed
Fewer segments – faster searches
4
01
Search – Importance of Segments
Immutable – write once read many
More segments – slower search speed
Fewer segments – faster searches
Fewer segments – smaller shard size
4
01
Search – Importance of Segments
Immutable – write once read many
More segments – slower search speed
Fewer segments – faster searches
Fewer segments – smaller shard size
Rapid segment changes – worse I/O cache usage
4
01
Taking Control
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">5120</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
4
01
Taking Control
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">5120</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
Merge Scheduler
<mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler" />
4
01
Taking Control
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">5120</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
Merge Scheduler
<mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler" />
Segment Warmer
<mergedSegmentWarmer
class="org.apache.lucene.index.SimpleMergedSegmentWarmer" />
4
01
Taking Control – Default Indexing Throughput
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">5120</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
4
01
Taking Control – Default Indexing Throughput
throughput < 5k/sec @ ~14GB
4
01
Taking Control – Max Merged Segment Size
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">5120</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
Lower higher indexing throughput – smaller segments
Higher better search latency (depends) – more merges
4
01
Taking Control – Lowering Max Merged Size
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">512</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
4
01
Taking Control – Lowering Max Segment Size
throughput < 5k/sec @ ~15.5GB
11% throughput increase
5
01
Taking Control – Merge At Once
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">5120</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
Lower better search latency (depends)
Higher higher indexing throughput
5
01
Taking Control – Lowering Merge At Once
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">2</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">5120</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
5
01
Taking Control – Lowering Merge At Once
throughput < 5k/sec @ ~13GB
8% throughput decrease
5
01
Taking Control – Merge At Once Explicit
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">5120</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
Controls number of segments merged at once during force merge
5
01
Taking Control – Segments Per Tier
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">5120</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
Lower value means more merging, but less segments
Along with maxMergeAtOnce can smoothen I/O spikes
For better indexing throughput set maxMergeAtOnce <
segmentsPerTier
5
01
Taking Control – Combined Together
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">30</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">30</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">512</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
5
01
Taking Control – Combined Together
throughput < 5k/sec @ ~15GB
but look at read difference
5
01
Taking Control – Default vs Combined Read/Write
default settings
5
01
Taking Control – Default vs Combined Read/Write
default settings combined changes settings
5
01
Taking Control – Reclaim Deletes Weight
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">5120</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
Controls importance of merging segments with deleted documents
Increase to put priority on merging segments with deleted documents
6
01
Taking Control – No CFS Ratio
Merge Policy Factory
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="maxMergeAtOnceExplicit">30</int>
<int name="segmentsPerTier">10</int>
<int name="floorSegmentMB">2048</int>
<int name="maxMergedSegmentMB">5120</int>
<double name="noCFSRatio">0.1</double>
<int name="maxCFSSegmentSizeMB">2048</int>
<double name="reclaimDeletesWeight">2.0</double>
<double name="forceMergeDeletesPctAllowed">10.0</double>
</mergePolicyFactory>
Controls compound file system segments ratio
To completely disable CFS set to 0.0
6
01
Taking Control – Merge Scheduler
Controls maximum number of concurrent merges
Merge Scheduler
<mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler">
<int name="maxMergeCount">4</int>
<int name="maxThreadCount">4</int>
</mergeScheduler>
6
01
Taking Control – Merge Scheduler
Controls number of threads dedicated to merging
Merge Scheduler
<mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler">
<int name="maxMergeCount">4</int>
<int name="maxThreadCount">4</int>
</mergeScheduler>
6
01
Taking Control – Merge Scheduler
Controls number of threads dedicated to merging
For spinning drives set maxThreadCount to 1
Merge Scheduler
<mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler">
<int name="maxMergeCount">4</int>
<int name="maxThreadCount">4</int>
</mergeScheduler>
6
01
Taking Control – Merge Scheduler
Controls number of threads dedicated to merging
For spinning drives set maxThreadCount to 1
For SSD set maxThreadCount to min(4, #CPUs / 2)
Merge Scheduler
<mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler">
<int name="maxMergeCount">4</int>
<int name="maxThreadCount">4</int>
</mergeScheduler>
6
01
Optimize aka Force Merge
Forces segment merge – usually very expensive
6
01
Optimize aka Force Merge
Forces segment merge – usually very expensive
Desired number of segments can be specified
6
01
Optimize aka Force Merge
Forces segment merge – usually very expensive
Desired number of segments can be specified
Done on all shards at the same time (by default)
6
01
Optimize aka Force Merge
Forces segment merge – usually very expensive
Desired number of segments can be specified
Done on all shards at the same time (by default)
Can be very bad or very good – depending on the use case
6
01
Optimize aka Force Merge
Forces segment merge – usually very expensive
Desired number of segments can be specified
Done on all shards at the same time (by default)
Can be very bad or very good – depending on the use case
$ curl
'http://solr:8983/solr/lr/update?optimize=true&numSegments=1&waitFlush=false'
7
01
Force Merge – The Good
Improves search speed (fewer segments)
7
01
Force Merge – The Good
Improves search speed (fewer segments)
Removes deleted documents
7
01
Force Merge – The Good
Improves search speed (fewer segments)
Removes deleted documents
Shrinks the index by pruning duplicated data
7
01
Force Merge – The Good
Improves search speed (fewer segments)
Removes deleted documents
Shrinks the index by pruning duplicated data
Reduces number of used files
7
01
Force Merge – The Bad
Invalidates operating system I/O cache
7
01
Force Merge – The Bad
Invalidates operating system I/O cache
Very expensive to perform – rewrites all segments
7
01
Force Merge – The Bad
Invalidates operating system I/O cache
Very expensive to perform – rewrites all segments
Not efficient on changing data
7
01
Force Merge – The Bad
Invalidates operating system I/O cache
Very expensive to perform – rewrites all segments
Not efficient on changing data
May cause performance issues
7
01
Force Merge – The Bad
Invalidates operating system I/O cache
Very expensive to perform – rewrites all segments
Not efficient on changing data
May cause performance issues
Will cause temporary increase of disk usage (up to 3x)
7
01
Force Merge – SolrCloud Performance Example
8
01
Force Merge – SolrCloud Performance Example
8
01
Force Merge – Legacy
Index on the master server
Solr Master
Solr Slave
Solr Slave
Solr Slave
index
Documents
8
01
Force Merge – Legacy
Index on the master server
Force merge on the master server
Solr Master
Solr Slave
Solr Slave
Solr Slave
force merge
8
01
Force Merge – Legacy
Index on the master server
Force merge on the master server
Replicate after optimize is done
Solr Master
Solr Slave
Solr Slave
Solr Slave
pull after optimize
8
01
Force Merge – SolrCloud (Solr 7 – pull replicas)
Create collection
Force merge
Solr will do the rest
Solr Solr
Solr Solr
Primary 1
Primary 2 Pull Replica 2
Pull Replica 1
8
01
Force Merge – SolrCloud (NRT, pre 7.0)
Ask yourself if you really need force merge
Solr Solr
Solr Solr
8
01
Force Merge – SolrCloud (NRT replicas, pre 7.0)
Ask yourself if you really need force merge
Create collection on part of the nodes
Solr Solr
Solr Solr
Primary 1
Primary 2
8
01
Force Merge – SolrCloud (NRT replicas, pre 7.0)
Ask yourself if you really need force merge
Create collection on part of the nodes
Index
Solr Solr
Solr Solr
Primary 1
Primary 2
DocumentsDocuments
Documents
Documents
8
01
Force Merge – SolrCloud (NRT replicas, pre 7.0)
Ask yourself if you really need force merge
Create collection on part of the nodes
Index
Force merge
Solr Solr
Solr Solr
Primary 1
Primary 2optimize
8
01
Force Merge – SolrCloud (NRT replicas, pre 7.0)
Ask yourself if you really need force merge
Create collection on part of the nodes
Index
Force merge
Create replicas
Solr Solr
Solr Solr
Primary 1
Primary 2 Replica 2
Replica 1
9
01
Specialized Merge Policy Example – Sorting
Sorting Merge Policy Factory Example
<mergePolicyFactory class="org.apache.solr.index.SortingMergePolicyFactory">
<str name="sort">timestamp desc</str>
<str name="wrapper.prefix">inner</str>
<str name="inner.class">org.apache.solr.index.TieredMergePolicyFactory</str>
<int name="inner.maxMergeAtOnce">10</int>
<int name="inner.segmentsPerTier">10</int>
<double name="inner.noCFSRatio">0.1</double>
</mergePolicyFactory>
9
01
Specialized Merge Policy Example – Sorting
Sorting Merge Policy Factory Example
<mergePolicyFactory class="org.apache.solr.index.SortingMergePolicyFactory">
<str name="sort">timestamp desc</str>
<str name="wrapper.prefix">inner</str>
<str name="inner.class">org.apache.solr.index.TieredMergePolicyFactory</str>
<int name="inner.maxMergeAtOnce">10</int>
<int name="inner.segmentsPerTier">10</int>
<double name="inner.noCFSRatio">0.1</double>
</mergePolicyFactory>
Pre-sorts data during merge for:
- faster range queries
- faster data retrieval
- possibility of early query termination
- convenient for time based data
9
01
http://sematext.com/jobs
You love like we do?
You want to work with ?
Want to work with open source?
You want to do fun stuff?
9
01
Get in touch
Rafał
rafal.kuc@sematext.com
@kucrafal
http://sematext.com
@sematext http://sematext.com/jobs
Come talk to us
at the booth
Thank You

Solr Search Engine: Optimize Is (Not) Bad for You

  • 1.
    Optimize Is (Not)Bad For You Deep Dive Into The Segment Merge Abyss Rafał Kuć Sematext Group, Inc.
  • 2.
    Agenda • Segments –where, what & how • Writing segments • Modifying segments • Segment merging – what, where, how, why • Force merging • Force merging & SolrCloud • Performance considerations • Specialized merge policies https://github.com/sematext/lr/tree/master/2017/optimize
  • 3.
  • 4.
  • 5.
  • 6.
    6 01 Solr Collection Architecture Zookeeper SOLR shardshard SOLR shard shard SOLR shard shard SOLR shard shard
  • 7.
  • 8.
  • 9.
    9 01 Lucene Segment Segment Info FieldNames Stored Field Values Point Values Term Dictionary Term Frequency Term Proximity Normalization Per Document Vals Live Documents
  • 10.
    1 01 Inside the Segment– Term Dictionary TERM DOCID lucene <1>, <2> revolution <1>, <2> washington <1> boston <2> _1.tim Doc1 Title: Lucene Revolution Washington, City: Washington D.C Doc2 Title: Lucene Revolution Boston, City: Boston _1.tip
  • 11.
    1 01 Inside the Segment– Doc Values Doc1 Title: Lucene Revolution Washington, City: Washington D.C Doc2 Title: Lucene Revolution Boston, City: Boston DOCID FIELD VALUE 1 Title Lucene Revolution Washington 1 City Washington D.C. 2 Title Lucene Revolution Boston 2 City Boston _1.dvd _1.dvm
  • 12.
    1 01 Inside the Segment– Stored Fields Doc1 Title: Lucene Revolution Washington, City: Washington D.C Doc2 Title: Lucene Revolution Boston, City: Boston DOCID VALUE 1 Title: Lucene Revolution Washington City: Washington D.C 2 Title: Lucene Revolution Boston City: Boston _1.fdx _1.fdt
  • 13.
    1 01 Inside the Segment– Compound File System _1.fdt _1.fdx _1.fnm _1.nvd _1.nvm _1.si _1.Lucene50_0.doc _1.Lucene50_0.pos _1.Lucene50_0.tim _1.Lucene50_0.tip _1.Lucene50_0.dvd _1.Lucene50_0.dvm
  • 14.
    1 01 Inside the Segment– Compound File System _1.fdt _1.fdx _1.fnm _1.nvd _1.nvm _1.si _1.Lucene50_0.doc _1.Lucene50_0.pos _1.Lucene50_0.tim _1.Lucene50_0.tip _1.Lucene50_0.dvd _1.Lucene50_0.dvm
  • 15.
    1 01 Inside the Segment– Compound File System _1.fdt _1.fdx _1.fnm _1.nvd _1.nvm _1.si _1.Lucene50_0.doc _1.Lucene50_0.pos _1.Lucene50_0.tim _1.Lucene50_0.tip _1.Lucene50_0.dvd _1.Lucene50_0.dvm _2.cfs _2.cfe
  • 16.
  • 17.
  • 18.
  • 19.
  • 20.
  • 21.
  • 22.
  • 23.
  • 24.
  • 25.
  • 26.
  • 27.
  • 28.
  • 29.
    2 01 Atomic Updates $ curl-XPOST -H 'Content-Type: application/json' 'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[ { "id" : "3", "tags" : { "add" : [ "solr" ] } } ]' retrieve document { "id" : 3, "tags" : [ "lucene" ], "awesome" : true }
  • 30.
    3 01 Atomic Updates $ curl-XPOST -H 'Content-Type: application/json' 'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[ { "id" : "3", "tags" : { "add" : [ "solr" ] } } ]' { "id" : 3, "tags" : [ "lucene", "solr" ], "awesome" : true } apply changes
  • 31.
    3 01 Atomic Updates $ curl-XPOST -H 'Content-Type: application/json' 'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[ { "id" : "3", "tags" : { "add" : [ "solr" ] } } ]' { "id" : 3, "tags" : [ "lucene", "solr" ], "awesome" : true } delete old document
  • 32.
    3 01 Atomic Updates $ curl-XPOST -H 'Content-Type: application/json' 'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[ { "id" : "3", "tags" : { "add" : [ "solr" ] } } ]' { "id" : 3, "tags" : [ "lucene", "solr" ], "awesome" : true }
  • 33.
    3 01 Atomic Updates –In Place Works on top of numeric, doc values based fields Fields need to be not indexed and not stored Doesn’t require delete/index Support only inc and set modifers $ curl -XPOST -H 'Content-Type: application/json' 'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[ { "id" : "3", "views" : { "inc" : 100 } } ]'
  • 34.
    3 01 Atomic Updates –In Place $ curl -XPOST -H 'Content-Type: application/json' 'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[ { "id" : "3", "views" : { "inc" : 100 } } ]' retrieve document { "id" : 3, "tags" : [ "lucene", "solr" ], "awesome" : true }
  • 35.
    3 01 Atomic Updates –In Place $ curl -XPOST -H 'Content-Type: application/json' 'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[ { "id" : "3", "views" : { "inc" : 100 } } ]' { "id" : 3, "tags" : [ "lucene", "solr" ], "awesome" : true, "views" : 100 } apply changes
  • 36.
    3 01 Atomic Updates –In Place $ curl -XPOST -H 'Content-Type: application/json' 'http://localhost:8983/solr/lr/update?commit=true' --data-binary '[ { "id" : "3", "views" : { "inc" : 100 } } ]' { "id" : 3, "tags" : [ "lucene", "solr" ], "awesome" : true, "views" : 100 } update doc values
  • 37.
    3 01 Search – Importanceof Segments Immutable – write once read many
  • 38.
    3 01 Search – Importanceof Segments Immutable – write once read many More segments – slower search speed
  • 39.
    3 01 Search – Importanceof Segments Immutable – write once read many More segments – slower search speed Fewer segments – faster searches
  • 40.
    4 01 Search – Importanceof Segments Immutable – write once read many More segments – slower search speed Fewer segments – faster searches Fewer segments – smaller shard size
  • 41.
    4 01 Search – Importanceof Segments Immutable – write once read many More segments – slower search speed Fewer segments – faster searches Fewer segments – smaller shard size Rapid segment changes – worse I/O cache usage
  • 42.
    4 01 Taking Control Merge PolicyFactory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">10</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">5120</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory>
  • 43.
    4 01 Taking Control Merge PolicyFactory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">10</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">5120</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory> Merge Scheduler <mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler" />
  • 44.
    4 01 Taking Control Merge PolicyFactory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">10</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">5120</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory> Merge Scheduler <mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler" /> Segment Warmer <mergedSegmentWarmer class="org.apache.lucene.index.SimpleMergedSegmentWarmer" />
  • 45.
    4 01 Taking Control –Default Indexing Throughput Merge Policy Factory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">10</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">5120</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory>
  • 46.
    4 01 Taking Control –Default Indexing Throughput throughput < 5k/sec @ ~14GB
  • 47.
    4 01 Taking Control –Max Merged Segment Size Merge Policy Factory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">10</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">5120</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory> Lower higher indexing throughput – smaller segments Higher better search latency (depends) – more merges
  • 48.
    4 01 Taking Control –Lowering Max Merged Size Merge Policy Factory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">10</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">512</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory>
  • 49.
    4 01 Taking Control –Lowering Max Segment Size throughput < 5k/sec @ ~15.5GB 11% throughput increase
  • 50.
    5 01 Taking Control –Merge At Once Merge Policy Factory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">10</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">5120</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory> Lower better search latency (depends) Higher higher indexing throughput
  • 51.
    5 01 Taking Control –Lowering Merge At Once Merge Policy Factory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">2</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">5120</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory>
  • 52.
    5 01 Taking Control –Lowering Merge At Once throughput < 5k/sec @ ~13GB 8% throughput decrease
  • 53.
    5 01 Taking Control –Merge At Once Explicit Merge Policy Factory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">10</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">5120</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory> Controls number of segments merged at once during force merge
  • 54.
    5 01 Taking Control –Segments Per Tier Merge Policy Factory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">10</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">5120</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory> Lower value means more merging, but less segments Along with maxMergeAtOnce can smoothen I/O spikes For better indexing throughput set maxMergeAtOnce < segmentsPerTier
  • 55.
    5 01 Taking Control –Combined Together Merge Policy Factory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">30</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">30</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">512</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory>
  • 56.
    5 01 Taking Control –Combined Together throughput < 5k/sec @ ~15GB but look at read difference
  • 57.
    5 01 Taking Control –Default vs Combined Read/Write default settings
  • 58.
    5 01 Taking Control –Default vs Combined Read/Write default settings combined changes settings
  • 59.
    5 01 Taking Control –Reclaim Deletes Weight Merge Policy Factory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">10</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">5120</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory> Controls importance of merging segments with deleted documents Increase to put priority on merging segments with deleted documents
  • 60.
    6 01 Taking Control –No CFS Ratio Merge Policy Factory <mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory"> <int name="maxMergeAtOnce">10</int> <int name="maxMergeAtOnceExplicit">30</int> <int name="segmentsPerTier">10</int> <int name="floorSegmentMB">2048</int> <int name="maxMergedSegmentMB">5120</int> <double name="noCFSRatio">0.1</double> <int name="maxCFSSegmentSizeMB">2048</int> <double name="reclaimDeletesWeight">2.0</double> <double name="forceMergeDeletesPctAllowed">10.0</double> </mergePolicyFactory> Controls compound file system segments ratio To completely disable CFS set to 0.0
  • 61.
    6 01 Taking Control –Merge Scheduler Controls maximum number of concurrent merges Merge Scheduler <mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler"> <int name="maxMergeCount">4</int> <int name="maxThreadCount">4</int> </mergeScheduler>
  • 62.
    6 01 Taking Control –Merge Scheduler Controls number of threads dedicated to merging Merge Scheduler <mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler"> <int name="maxMergeCount">4</int> <int name="maxThreadCount">4</int> </mergeScheduler>
  • 63.
    6 01 Taking Control –Merge Scheduler Controls number of threads dedicated to merging For spinning drives set maxThreadCount to 1 Merge Scheduler <mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler"> <int name="maxMergeCount">4</int> <int name="maxThreadCount">4</int> </mergeScheduler>
  • 64.
    6 01 Taking Control –Merge Scheduler Controls number of threads dedicated to merging For spinning drives set maxThreadCount to 1 For SSD set maxThreadCount to min(4, #CPUs / 2) Merge Scheduler <mergeScheduler class="org.apache.lucene.index.ConcurrentMergeScheduler"> <int name="maxMergeCount">4</int> <int name="maxThreadCount">4</int> </mergeScheduler>
  • 65.
    6 01 Optimize aka ForceMerge Forces segment merge – usually very expensive
  • 66.
    6 01 Optimize aka ForceMerge Forces segment merge – usually very expensive Desired number of segments can be specified
  • 67.
    6 01 Optimize aka ForceMerge Forces segment merge – usually very expensive Desired number of segments can be specified Done on all shards at the same time (by default)
  • 68.
    6 01 Optimize aka ForceMerge Forces segment merge – usually very expensive Desired number of segments can be specified Done on all shards at the same time (by default) Can be very bad or very good – depending on the use case
  • 69.
    6 01 Optimize aka ForceMerge Forces segment merge – usually very expensive Desired number of segments can be specified Done on all shards at the same time (by default) Can be very bad or very good – depending on the use case $ curl 'http://solr:8983/solr/lr/update?optimize=true&numSegments=1&waitFlush=false'
  • 70.
    7 01 Force Merge –The Good Improves search speed (fewer segments)
  • 71.
    7 01 Force Merge –The Good Improves search speed (fewer segments) Removes deleted documents
  • 72.
    7 01 Force Merge –The Good Improves search speed (fewer segments) Removes deleted documents Shrinks the index by pruning duplicated data
  • 73.
    7 01 Force Merge –The Good Improves search speed (fewer segments) Removes deleted documents Shrinks the index by pruning duplicated data Reduces number of used files
  • 74.
    7 01 Force Merge –The Bad Invalidates operating system I/O cache
  • 75.
    7 01 Force Merge –The Bad Invalidates operating system I/O cache Very expensive to perform – rewrites all segments
  • 76.
    7 01 Force Merge –The Bad Invalidates operating system I/O cache Very expensive to perform – rewrites all segments Not efficient on changing data
  • 77.
    7 01 Force Merge –The Bad Invalidates operating system I/O cache Very expensive to perform – rewrites all segments Not efficient on changing data May cause performance issues
  • 78.
    7 01 Force Merge –The Bad Invalidates operating system I/O cache Very expensive to perform – rewrites all segments Not efficient on changing data May cause performance issues Will cause temporary increase of disk usage (up to 3x)
  • 79.
    7 01 Force Merge –SolrCloud Performance Example
  • 80.
    8 01 Force Merge –SolrCloud Performance Example
  • 81.
    8 01 Force Merge –Legacy Index on the master server Solr Master Solr Slave Solr Slave Solr Slave index Documents
  • 82.
    8 01 Force Merge –Legacy Index on the master server Force merge on the master server Solr Master Solr Slave Solr Slave Solr Slave force merge
  • 83.
    8 01 Force Merge –Legacy Index on the master server Force merge on the master server Replicate after optimize is done Solr Master Solr Slave Solr Slave Solr Slave pull after optimize
  • 84.
    8 01 Force Merge –SolrCloud (Solr 7 – pull replicas) Create collection Force merge Solr will do the rest Solr Solr Solr Solr Primary 1 Primary 2 Pull Replica 2 Pull Replica 1
  • 85.
    8 01 Force Merge –SolrCloud (NRT, pre 7.0) Ask yourself if you really need force merge Solr Solr Solr Solr
  • 86.
    8 01 Force Merge –SolrCloud (NRT replicas, pre 7.0) Ask yourself if you really need force merge Create collection on part of the nodes Solr Solr Solr Solr Primary 1 Primary 2
  • 87.
    8 01 Force Merge –SolrCloud (NRT replicas, pre 7.0) Ask yourself if you really need force merge Create collection on part of the nodes Index Solr Solr Solr Solr Primary 1 Primary 2 DocumentsDocuments Documents Documents
  • 88.
    8 01 Force Merge –SolrCloud (NRT replicas, pre 7.0) Ask yourself if you really need force merge Create collection on part of the nodes Index Force merge Solr Solr Solr Solr Primary 1 Primary 2optimize
  • 89.
    8 01 Force Merge –SolrCloud (NRT replicas, pre 7.0) Ask yourself if you really need force merge Create collection on part of the nodes Index Force merge Create replicas Solr Solr Solr Solr Primary 1 Primary 2 Replica 2 Replica 1
  • 90.
    9 01 Specialized Merge PolicyExample – Sorting Sorting Merge Policy Factory Example <mergePolicyFactory class="org.apache.solr.index.SortingMergePolicyFactory"> <str name="sort">timestamp desc</str> <str name="wrapper.prefix">inner</str> <str name="inner.class">org.apache.solr.index.TieredMergePolicyFactory</str> <int name="inner.maxMergeAtOnce">10</int> <int name="inner.segmentsPerTier">10</int> <double name="inner.noCFSRatio">0.1</double> </mergePolicyFactory>
  • 91.
    9 01 Specialized Merge PolicyExample – Sorting Sorting Merge Policy Factory Example <mergePolicyFactory class="org.apache.solr.index.SortingMergePolicyFactory"> <str name="sort">timestamp desc</str> <str name="wrapper.prefix">inner</str> <str name="inner.class">org.apache.solr.index.TieredMergePolicyFactory</str> <int name="inner.maxMergeAtOnce">10</int> <int name="inner.segmentsPerTier">10</int> <double name="inner.noCFSRatio">0.1</double> </mergePolicyFactory> Pre-sorts data during merge for: - faster range queries - faster data retrieval - possibility of early query termination - convenient for time based data
  • 92.
    9 01 http://sematext.com/jobs You love likewe do? You want to work with ? Want to work with open source? You want to do fun stuff?
  • 93.
  • 94.