[jira] Commented: (SOLR-1375) BloomFilter on a field
[ https://issues.apache.org/jira/browse/SOLR-1375?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12745774#action_12745774 ] Lance Norskog commented on SOLR-1375: - At my previous job, we were attempting to add the same document up to 100x per day. We used an MD5 signature for the id and made a bitmap file to pre-check ids before attempting to add them. Because we did not created a bitmap file with 2^32 bits (512M) instead of (2^128) we also had a false positive problem which we were willing to put up with. (It was ok if we did not add all documents. ) We also had the advantage that different feeding machines pulled documents from different sources, and so machine A's set of repeated documents was separate from machine B's. Therefore, each could keep its own bitmap file and the files could be OR'd together periodically in background. I can't recommend what we did. If you like the Bloom Filter for this problem, that's great. This project: [FastBits IBIS|http://crd.lbl.gov/~kewu/fastbit/doc/html/index.html] claims to be super-smart about compressing bits in a disk archive. It might be a better technology than the Nutch Bloom Filter, but who cares. > BloomFilter on a field > -- > > Key: SOLR-1375 > URL: https://issues.apache.org/jira/browse/SOLR-1375 > Project: Solr > Issue Type: New Feature > Components: update >Affects Versions: 1.4 >Reporter: Jason Rutherglen >Priority: Minor > Fix For: 1.5 > > Attachments: SOLR-1375.patch > > Original Estimate: 120h > Remaining Estimate: 120h > > * A bloom filter is a read only probabilistic set. Its useful > for verifying a key exists in a set, though it returns false > positives. http://en.wikipedia.org/wiki/Bloom_filter > * The use case is indexing in Hadoop and checking for duplicates > against a Solr cluster (which when using term dictionary or a > query) is too slow and exceeds the time consumed for indexing. > When a match is found, the host, segment, and term are returned. > If the same term is found on multiple servers, multiple results > are returned by the distributed process. (We'll need to add in > the core name I just realized). > * When new segments are created, and commit is called, a new > bloom filter is generated from a given field (default:id) by > iterating over the term dictionary values. There's a bloom > filter file per segment, which is managed on each Solr shard. > When segments are merged away, their corresponding .blm files is > also removed. In a future version we'll have a central server > for the bloom filters so we're not abusing the thread pool of > the Solr proxy and the networking of the Solr cluster (this will > be done sooner than later after testing this version). I held > off because the central server requires syncing the Solr > servers' files (which is like reverse replication). > * The patch uses the BloomFilter from Hadoop 0.20. I want to jar > up only the necessary classes so we don't have a giant Hadoop > jar in lib. > http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/util/bloom/BloomFilter.html > * Distributed code is added and seems to work, I extended > TestDistributedSearch to test over multiple HTTP servers. I > chose this approach rather than the manual method used by (for > example) TermVectorComponent.testDistributed because I'm new to > Solr's distributed search and wanted to learn how it works (the > stages are confusing). Using this method, I didn't need to setup > multiple tomcat servers and manually execute tests. > * We need more of the bloom filter options passable via > solrconfig > * I'll add more test cases -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (SOLR-1375) BloomFilter on a field
[ https://issues.apache.org/jira/browse/SOLR-1375?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12745800#action_12745800 ] Jason Rutherglen commented on SOLR-1375: Lance, Thanks for the info. BloomFilters can be ORed together. Hadoop uses BFs for map side joins, which is similar to this use case. Centralizing will help when performing millions of id membership tests, though I'm going to benchmark first and see if the current patch is good enough. -J > BloomFilter on a field > -- > > Key: SOLR-1375 > URL: https://issues.apache.org/jira/browse/SOLR-1375 > Project: Solr > Issue Type: New Feature > Components: update >Affects Versions: 1.4 >Reporter: Jason Rutherglen >Priority: Minor > Fix For: 1.5 > > Attachments: SOLR-1375.patch > > Original Estimate: 120h > Remaining Estimate: 120h > > * A bloom filter is a read only probabilistic set. Its useful > for verifying a key exists in a set, though it returns false > positives. http://en.wikipedia.org/wiki/Bloom_filter > * The use case is indexing in Hadoop and checking for duplicates > against a Solr cluster (which when using term dictionary or a > query) is too slow and exceeds the time consumed for indexing. > When a match is found, the host, segment, and term are returned. > If the same term is found on multiple servers, multiple results > are returned by the distributed process. (We'll need to add in > the core name I just realized). > * When new segments are created, and commit is called, a new > bloom filter is generated from a given field (default:id) by > iterating over the term dictionary values. There's a bloom > filter file per segment, which is managed on each Solr shard. > When segments are merged away, their corresponding .blm files is > also removed. In a future version we'll have a central server > for the bloom filters so we're not abusing the thread pool of > the Solr proxy and the networking of the Solr cluster (this will > be done sooner than later after testing this version). I held > off because the central server requires syncing the Solr > servers' files (which is like reverse replication). > * The patch uses the BloomFilter from Hadoop 0.20. I want to jar > up only the necessary classes so we don't have a giant Hadoop > jar in lib. > http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/util/bloom/BloomFilter.html > * Distributed code is added and seems to work, I extended > TestDistributedSearch to test over multiple HTTP servers. I > chose this approach rather than the manual method used by (for > example) TermVectorComponent.testDistributed because I'm new to > Solr's distributed search and wanted to learn how it works (the > stages are confusing). Using this method, I didn't need to setup > multiple tomcat servers and manually execute tests. > * We need more of the bloom filter options passable via > solrconfig > * I'll add more test cases -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (SOLR-1375) BloomFilter on a field
[ https://issues.apache.org/jira/browse/SOLR-1375?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12746591#action_12746591 ] Andrzej Bialecki commented on SOLR-1375: - See here for a Java impl. of FastBits: http://code.google.com/p/compressedbitset/ . Re: BloomFilters - in BloomIndexComponent you seem to assume that when BloomKeySet.contains(key) returns true then a key exists in a set. This is not strictly speaking true. You can only be sure with 1.0 probability that a key does NOT exist in a set, for other key when the result is true you only have a (1.0 - eps) probability that the answer is correct, i.e. the BloomFilter will return a false positive result for non-existent keys, with (eps) probability. You should take this into account when writing client code. > BloomFilter on a field > -- > > Key: SOLR-1375 > URL: https://issues.apache.org/jira/browse/SOLR-1375 > Project: Solr > Issue Type: New Feature > Components: update >Affects Versions: 1.4 >Reporter: Jason Rutherglen >Priority: Minor > Fix For: 1.5 > > Attachments: SOLR-1375.patch, SOLR-1375.patch, SOLR-1375.patch > > Original Estimate: 120h > Remaining Estimate: 120h > > * A bloom filter is a read only probabilistic set. Its useful > for verifying a key exists in a set, though it returns false > positives. http://en.wikipedia.org/wiki/Bloom_filter > * The use case is indexing in Hadoop and checking for duplicates > against a Solr cluster (which when using term dictionary or a > query) is too slow and exceeds the time consumed for indexing. > When a match is found, the host, segment, and term are returned. > If the same term is found on multiple servers, multiple results > are returned by the distributed process. (We'll need to add in > the core name I just realized). > * When new segments are created, and commit is called, a new > bloom filter is generated from a given field (default:id) by > iterating over the term dictionary values. There's a bloom > filter file per segment, which is managed on each Solr shard. > When segments are merged away, their corresponding .blm files is > also removed. In a future version we'll have a central server > for the bloom filters so we're not abusing the thread pool of > the Solr proxy and the networking of the Solr cluster (this will > be done sooner than later after testing this version). I held > off because the central server requires syncing the Solr > servers' files (which is like reverse replication). > * The patch uses the BloomFilter from Hadoop 0.20. I want to jar > up only the necessary classes so we don't have a giant Hadoop > jar in lib. > http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/util/bloom/BloomFilter.html > * Distributed code is added and seems to work, I extended > TestDistributedSearch to test over multiple HTTP servers. I > chose this approach rather than the manual method used by (for > example) TermVectorComponent.testDistributed because I'm new to > Solr's distributed search and wanted to learn how it works (the > stages are confusing). Using this method, I didn't need to setup > multiple tomcat servers and manually execute tests. > * We need more of the bloom filter options passable via > solrconfig > * I'll add more test cases -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (SOLR-1375) BloomFilter on a field
[ https://issues.apache.org/jira/browse/SOLR-1375?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12747734#action_12747734 ] Jason Rutherglen commented on SOLR-1375: The other attribute to add is the ability to set the hash function to use (i.e. Murmur) > BloomFilter on a field > -- > > Key: SOLR-1375 > URL: https://issues.apache.org/jira/browse/SOLR-1375 > Project: Solr > Issue Type: New Feature > Components: update >Affects Versions: 1.4 >Reporter: Jason Rutherglen >Priority: Minor > Fix For: 1.5 > > Attachments: SOLR-1375.patch, SOLR-1375.patch, SOLR-1375.patch, > SOLR-1375.patch > > Original Estimate: 120h > Remaining Estimate: 120h > > * A bloom filter is a read only probabilistic set. Its useful > for verifying a key exists in a set, though it returns false > positives. http://en.wikipedia.org/wiki/Bloom_filter > * The use case is indexing in Hadoop and checking for duplicates > against a Solr cluster (which when using term dictionary or a > query) is too slow and exceeds the time consumed for indexing. > When a match is found, the host, segment, and term are returned. > If the same term is found on multiple servers, multiple results > are returned by the distributed process. (We'll need to add in > the core name I just realized). > * When new segments are created, and commit is called, a new > bloom filter is generated from a given field (default:id) by > iterating over the term dictionary values. There's a bloom > filter file per segment, which is managed on each Solr shard. > When segments are merged away, their corresponding .blm files is > also removed. In a future version we'll have a central server > for the bloom filters so we're not abusing the thread pool of > the Solr proxy and the networking of the Solr cluster (this will > be done sooner than later after testing this version). I held > off because the central server requires syncing the Solr > servers' files (which is like reverse replication). > * The patch uses the BloomFilter from Hadoop 0.20. I want to jar > up only the necessary classes so we don't have a giant Hadoop > jar in lib. > http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/util/bloom/BloomFilter.html > * Distributed code is added and seems to work, I extended > TestDistributedSearch to test over multiple HTTP servers. I > chose this approach rather than the manual method used by (for > example) TermVectorComponent.testDistributed because I'm new to > Solr's distributed search and wanted to learn how it works (the > stages are confusing). Using this method, I didn't need to setup > multiple tomcat servers and manually execute tests. > * We need more of the bloom filter options passable via > solrconfig > * I'll add more test cases -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
