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Jeremy Hanna edited comment on CASSANDRA-3843 at 2/21/12 2:30 PM: ------------------------------------------------------------------ I did repairs on all the nodes and then compacts on all the nodes. Then I did a pig job to simply count the number of rows in the column family. Again I think the overall writes were reduced but there are writes going on. I need to turn debug on and do the same test again. I did the compactions at 6:42 and the range scans at 14:16: {code} -rw-r--r-- 1 root root 40106228511 Feb 21 06:42 account_snapshot-g-792-Data.db -rw-r--r-- 1 root root 206884816 Feb 21 06:42 account_snapshot-g-792-Filter.db -rw-r--r-- 1 root root 2913796038 Feb 21 06:42 account_snapshot-g-792-Index.db -rw-r--r-- 1 root root 4276 Feb 21 06:42 account_snapshot-g-792-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-793-Compacted -rw-r--r-- 1 root root 287286 Feb 21 14:16 account_snapshot-g-793-Data.db -rw-r--r-- 1 root root 976 Feb 21 14:16 account_snapshot-g-793-Filter.db -rw-r--r-- 1 root root 20857 Feb 21 14:16 account_snapshot-g-793-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:16 account_snapshot-g-793-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-794-Compacted -rw-r--r-- 1 root root 87770771 Feb 21 14:17 account_snapshot-g-794-Data.db -rw-r--r-- 1 root root 293944 Feb 21 14:17 account_snapshot-g-794-Filter.db -rw-r--r-- 1 root root 6377968 Feb 21 14:17 account_snapshot-g-794-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:17 account_snapshot-g-794-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-795-Compacted -rw-r--r-- 1 root root 78459166 Feb 21 14:17 account_snapshot-g-795-Data.db -rw-r--r-- 1 root root 262600 Feb 21 14:17 account_snapshot-g-795-Filter.db -rw-r--r-- 1 root root 5698156 Feb 21 14:17 account_snapshot-g-795-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:17 account_snapshot-g-795-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-796-Compacted -rw-r--r-- 1 root root 69838937 Feb 21 14:17 account_snapshot-g-796-Data.db -rw-r--r-- 1 root root 234000 Feb 21 14:17 account_snapshot-g-796-Filter.db -rw-r--r-- 1 root root 5077447 Feb 21 14:17 account_snapshot-g-796-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:17 account_snapshot-g-796-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-797-Compacted -rw-r--r-- 1 root root 68094433 Feb 21 14:17 account_snapshot-g-797-Data.db -rw-r--r-- 1 root root 227808 Feb 21 14:17 account_snapshot-g-797-Filter.db -rw-r--r-- 1 root root 4943098 Feb 21 14:17 account_snapshot-g-797-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:17 account_snapshot-g-797-Statistics.db -rw-r--r-- 1 root root 304163307 Feb 21 14:20 account_snapshot-g-798-Data.db -rw-r--r-- 1 root root 1019776 Feb 21 14:20 account_snapshot-g-798-Filter.db -rw-r--r-- 1 root root 22096669 Feb 21 14:20 account_snapshot-g-798-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:20 account_snapshot-g-798-Statistics.db -rw-r--r-- 1 root root 65874829 Feb 21 14:18 account_snapshot-g-799-Data.db -rw-r--r-- 1 root root 220192 Feb 21 14:18 account_snapshot-g-799-Filter.db -rw-r--r-- 1 root root 4777809 Feb 21 14:18 account_snapshot-g-799-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:18 account_snapshot-g-799-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-800-Compacted -rw-r--r-- 1 root root 50067413 Feb 21 14:18 account_snapshot-g-800-Data.db -rw-r--r-- 1 root root 167416 Feb 21 14:18 account_snapshot-g-800-Filter.db -rw-r--r-- 1 root root 3632313 Feb 21 14:18 account_snapshot-g-800-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:18 account_snapshot-g-800-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-801-Compacted -rw-r--r-- 1 root root 50575719 Feb 21 14:18 account_snapshot-g-801-Data.db -rw-r--r-- 1 root root 169160 Feb 21 14:18 account_snapshot-g-801-Filter.db -rw-r--r-- 1 root root 3669880 Feb 21 14:18 account_snapshot-g-801-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:18 account_snapshot-g-801-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-802-Compacted -rw-r--r-- 1 root root 41788766 Feb 21 14:19 account_snapshot-g-802-Data.db -rw-r--r-- 1 root root 139776 Feb 21 14:19 account_snapshot-g-802-Filter.db -rw-r--r-- 1 root root 3033069 Feb 21 14:19 account_snapshot-g-802-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:19 account_snapshot-g-802-Statistics.db -rw-r--r-- 1 root root 46547146 Feb 21 14:19 account_snapshot-g-803-Data.db -rw-r--r-- 1 root root 155720 Feb 21 14:19 account_snapshot-g-803-Filter.db -rw-r--r-- 1 root root 3378457 Feb 21 14:19 account_snapshot-g-803-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:19 account_snapshot-g-803-Statistics.db -rw-r--r-- 1 root root 142719184 Feb 21 14:20 account_snapshot-g-804-Data.db -rw-r--r-- 1 root root 478576 Feb 21 14:19 account_snapshot-g-804-Filter.db -rw-r--r-- 1 root root 10356119 Feb 21 14:20 account_snapshot-g-804-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:20 account_snapshot-g-804-Statistics.db -rw-r--r-- 1 root root 55373874 Feb 21 14:19 account_snapshot-g-805-Data.db -rw-r--r-- 1 root root 185160 Feb 21 14:19 account_snapshot-g-805-Filter.db -rw-r--r-- 1 root root 4017391 Feb 21 14:19 account_snapshot-g-805-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:19 account_snapshot-g-805-Statistics.db -rw-r--r-- 1 root root 46399227 Feb 21 14:19 account_snapshot-g-806-Data.db -rw-r--r-- 1 root root 155120 Feb 21 14:19 account_snapshot-g-806-Filter.db -rw-r--r-- 1 root root 3365947 Feb 21 14:19 account_snapshot-g-806-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:19 account_snapshot-g-806-Statistics.db -rw-r--r-- 1 root root 58491393 Feb 21 14:19 account_snapshot-g-807-Data.db -rw-r--r-- 1 root root 196048 Feb 21 14:19 account_snapshot-g-807-Filter.db -rw-r--r-- 1 root root 4253922 Feb 21 14:19 account_snapshot-g-807-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:19 account_snapshot-g-807-Statistics.db -rw-r--r-- 1 root root 47609635 Feb 21 14:20 account_snapshot-g-808-Data.db -rw-r--r-- 1 root root 159320 Feb 21 14:20 account_snapshot-g-808-Filter.db -rw-r--r-- 1 root root 3456985 Feb 21 14:20 account_snapshot-g-808-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:20 account_snapshot-g-808-Statistics.db -rw-r--r-- 1 root root 46923060 Feb 21 14:20 account_snapshot-tmp-g-809-Data.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-tmp-g-809-Index.db -rw-r--r-- 1 root root 49693602 Feb 21 14:20 account_snapshot-tmp-g-810-Data.db -rw-r--r-- 1 root root 166600 Feb 21 14:20 account_snapshot-tmp-g-810-Filter.db -rw-r--r-- 1 root root 3614750 Feb 21 14:20 account_snapshot-tmp-g-810-Index.db {code} was (Author: jeromatron): I did repairs on all the nodes and then compacts on all the nodes. Then I did a pig job to simply count the number of rows in the column family. Again I think the overall writes were reduced but there are writes going on. I need to turn debug on and do the same test again. I did the compactions at 6:42 and the range scans at 14:16: -rw-r--r-- 1 root root 40106228511 Feb 21 06:42 account_snapshot-g-792-Data.db -rw-r--r-- 1 root root 206884816 Feb 21 06:42 account_snapshot-g-792-Filter.db -rw-r--r-- 1 root root 2913796038 Feb 21 06:42 account_snapshot-g-792-Index.db -rw-r--r-- 1 root root 4276 Feb 21 06:42 account_snapshot-g-792-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-793-Compacted -rw-r--r-- 1 root root 287286 Feb 21 14:16 account_snapshot-g-793-Data.db -rw-r--r-- 1 root root 976 Feb 21 14:16 account_snapshot-g-793-Filter.db -rw-r--r-- 1 root root 20857 Feb 21 14:16 account_snapshot-g-793-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:16 account_snapshot-g-793-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-794-Compacted -rw-r--r-- 1 root root 87770771 Feb 21 14:17 account_snapshot-g-794-Data.db -rw-r--r-- 1 root root 293944 Feb 21 14:17 account_snapshot-g-794-Filter.db -rw-r--r-- 1 root root 6377968 Feb 21 14:17 account_snapshot-g-794-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:17 account_snapshot-g-794-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-795-Compacted -rw-r--r-- 1 root root 78459166 Feb 21 14:17 account_snapshot-g-795-Data.db -rw-r--r-- 1 root root 262600 Feb 21 14:17 account_snapshot-g-795-Filter.db -rw-r--r-- 1 root root 5698156 Feb 21 14:17 account_snapshot-g-795-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:17 account_snapshot-g-795-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-796-Compacted -rw-r--r-- 1 root root 69838937 Feb 21 14:17 account_snapshot-g-796-Data.db -rw-r--r-- 1 root root 234000 Feb 21 14:17 account_snapshot-g-796-Filter.db -rw-r--r-- 1 root root 5077447 Feb 21 14:17 account_snapshot-g-796-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:17 account_snapshot-g-796-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-797-Compacted -rw-r--r-- 1 root root 68094433 Feb 21 14:17 account_snapshot-g-797-Data.db -rw-r--r-- 1 root root 227808 Feb 21 14:17 account_snapshot-g-797-Filter.db -rw-r--r-- 1 root root 4943098 Feb 21 14:17 account_snapshot-g-797-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:17 account_snapshot-g-797-Statistics.db -rw-r--r-- 1 root root 304163307 Feb 21 14:20 account_snapshot-g-798-Data.db -rw-r--r-- 1 root root 1019776 Feb 21 14:20 account_snapshot-g-798-Filter.db -rw-r--r-- 1 root root 22096669 Feb 21 14:20 account_snapshot-g-798-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:20 account_snapshot-g-798-Statistics.db -rw-r--r-- 1 root root 65874829 Feb 21 14:18 account_snapshot-g-799-Data.db -rw-r--r-- 1 root root 220192 Feb 21 14:18 account_snapshot-g-799-Filter.db -rw-r--r-- 1 root root 4777809 Feb 21 14:18 account_snapshot-g-799-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:18 account_snapshot-g-799-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-800-Compacted -rw-r--r-- 1 root root 50067413 Feb 21 14:18 account_snapshot-g-800-Data.db -rw-r--r-- 1 root root 167416 Feb 21 14:18 account_snapshot-g-800-Filter.db -rw-r--r-- 1 root root 3632313 Feb 21 14:18 account_snapshot-g-800-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:18 account_snapshot-g-800-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-801-Compacted -rw-r--r-- 1 root root 50575719 Feb 21 14:18 account_snapshot-g-801-Data.db -rw-r--r-- 1 root root 169160 Feb 21 14:18 account_snapshot-g-801-Filter.db -rw-r--r-- 1 root root 3669880 Feb 21 14:18 account_snapshot-g-801-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:18 account_snapshot-g-801-Statistics.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-g-802-Compacted -rw-r--r-- 1 root root 41788766 Feb 21 14:19 account_snapshot-g-802-Data.db -rw-r--r-- 1 root root 139776 Feb 21 14:19 account_snapshot-g-802-Filter.db -rw-r--r-- 1 root root 3033069 Feb 21 14:19 account_snapshot-g-802-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:19 account_snapshot-g-802-Statistics.db -rw-r--r-- 1 root root 46547146 Feb 21 14:19 account_snapshot-g-803-Data.db -rw-r--r-- 1 root root 155720 Feb 21 14:19 account_snapshot-g-803-Filter.db -rw-r--r-- 1 root root 3378457 Feb 21 14:19 account_snapshot-g-803-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:19 account_snapshot-g-803-Statistics.db -rw-r--r-- 1 root root 142719184 Feb 21 14:20 account_snapshot-g-804-Data.db -rw-r--r-- 1 root root 478576 Feb 21 14:19 account_snapshot-g-804-Filter.db -rw-r--r-- 1 root root 10356119 Feb 21 14:20 account_snapshot-g-804-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:20 account_snapshot-g-804-Statistics.db -rw-r--r-- 1 root root 55373874 Feb 21 14:19 account_snapshot-g-805-Data.db -rw-r--r-- 1 root root 185160 Feb 21 14:19 account_snapshot-g-805-Filter.db -rw-r--r-- 1 root root 4017391 Feb 21 14:19 account_snapshot-g-805-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:19 account_snapshot-g-805-Statistics.db -rw-r--r-- 1 root root 46399227 Feb 21 14:19 account_snapshot-g-806-Data.db -rw-r--r-- 1 root root 155120 Feb 21 14:19 account_snapshot-g-806-Filter.db -rw-r--r-- 1 root root 3365947 Feb 21 14:19 account_snapshot-g-806-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:19 account_snapshot-g-806-Statistics.db -rw-r--r-- 1 root root 58491393 Feb 21 14:19 account_snapshot-g-807-Data.db -rw-r--r-- 1 root root 196048 Feb 21 14:19 account_snapshot-g-807-Filter.db -rw-r--r-- 1 root root 4253922 Feb 21 14:19 account_snapshot-g-807-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:19 account_snapshot-g-807-Statistics.db -rw-r--r-- 1 root root 47609635 Feb 21 14:20 account_snapshot-g-808-Data.db -rw-r--r-- 1 root root 159320 Feb 21 14:20 account_snapshot-g-808-Filter.db -rw-r--r-- 1 root root 3456985 Feb 21 14:20 account_snapshot-g-808-Index.db -rw-r--r-- 1 root root 4276 Feb 21 14:20 account_snapshot-g-808-Statistics.db -rw-r--r-- 1 root root 46923060 Feb 21 14:20 account_snapshot-tmp-g-809-Data.db -rw-r--r-- 1 root root 0 Feb 21 14:20 account_snapshot-tmp-g-809-Index.db -rw-r--r-- 1 root root 49693602 Feb 21 14:20 account_snapshot-tmp-g-810-Data.db -rw-r--r-- 1 root root 166600 Feb 21 14:20 account_snapshot-tmp-g-810-Filter.db -rw-r--r-- 1 root root 3614750 Feb 21 14:20 account_snapshot-tmp-g-810-Index.db > Unnecessary ReadRepair request during RangeScan > ------------------------------------------------ > > Key: CASSANDRA-3843 > URL: https://issues.apache.org/jira/browse/CASSANDRA-3843 > Project: Cassandra > Issue Type: Bug > Components: Core > Affects Versions: 1.0.0 > Reporter: Philip Andronov > Assignee: Jonathan Ellis > Fix For: 1.0.8 > > Attachments: 3843-v2.txt, 3843.txt > > > During reading with Quorum level and replication factor greater then 2, > Cassandra sends at least one ReadRepair, even if there is no need to do that. > With the fact that read requests await until ReadRepair will finish it slows > down requsts a lot, up to the Timeout :( > It seems that the problem has been introduced by the CASSANDRA-2494, > unfortunately I have no enought knowledge of Cassandra internals to fix the > problem and do not broke CASSANDRA-2494 functionality, so my report without a > patch. > Code explanations: > {code:title=RangeSliceResponseResolver.java|borderStyle=solid} > class RangeSliceResponseResolver { > // .... > private class Reducer extends > MergeIterator.Reducer<Pair<Row,InetAddress>, Row> > { > // .... > protected Row getReduced() > { > ColumnFamily resolved = versions.size() > 1 > ? > RowRepairResolver.resolveSuperset(versions) > : versions.get(0); > if (versions.size() < sources.size()) > { > for (InetAddress source : sources) > { > if (!versionSources.contains(source)) > { > > // [PA] Here we are adding null ColumnFamily. > // later it will be compared with the "desired" > // version and will give us "fake" difference which > // forces Cassandra to send ReadRepair to a given > source > versions.add(null); > versionSources.add(source); > } > } > } > // .... > if (resolved != null) > > repairResults.addAll(RowRepairResolver.scheduleRepairs(resolved, table, key, > versions, versionSources)); > // .... > } > } > } > {code} > {code:title=RowRepairResolver.java|borderStyle=solid} > public class RowRepairResolver extends AbstractRowResolver { > // .... > public static List<IAsyncResult> scheduleRepairs(ColumnFamily resolved, > String table, DecoratedKey<?> key, List<ColumnFamily> versions, > List<InetAddress> endpoints) > { > List<IAsyncResult> results = new > ArrayList<IAsyncResult>(versions.size()); > for (int i = 0; i < versions.size(); i++) > { > // On some iteration we have to compare null and resolved which > are obviously > // not equals, so it will fire a ReadRequest, however it is not > needed here > ColumnFamily diffCf = ColumnFamily.diff(versions.get(i), > resolved); > if (diffCf == null) > continue; > // .... > {code} > Imagine the following situation: > NodeA has X.1 // row X with the version 1 > NodeB has X.2 > NodeC has X.? // Unknown version, but because write was with Quorum it is 1 > or 2 > During the Quorum read from nodes A and B, Cassandra creates version 12 and > send ReadRepair, so now nodes has the following content: > NodeA has X.12 > NodeB has X.12 > which is correct, however Cassandra also will fire ReadRepair to NodeC. There > is no need to do that, the next consistent read have a chance to be served by > nodes {A, B} (no ReadRepair) or by pair {?, C} and in that case ReadRepair > will be fired and brings nodeC to the consistent state > Right now we are reading from the Index a lot and starting from some point in > time we are getting TimeOutException because cluster is overloaded by the > ReadRepairRequests *even* if all nodes has the same data :( -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira