[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Biju Nair updated HBASE-12790: -- Component/s: Scheduler > Support fairness across parallelized scans > -- > > Key: HBASE-12790 > URL: https://issues.apache.org/jira/browse/HBASE-12790 > Project: HBase > Issue Type: New Feature > Components: Scheduler >Reporter: James Taylor >Assignee: ramkrishna.s.vasudevan >Priority: Major > Labels: Phoenix > Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, > HBASE-12790_1.patch, HBASE-12790_5.patch, HBASE-12790_callwrapper.patch, > HBASE-12790_trunk_1.patch, PHOENIX_4.5.3-HBase-0.98-2317-SNAPSHOT.zip > > > Some HBase clients parallelize the execution of a scan to reduce latency in > getting back results. This can lead to starvation with a loaded cluster and > interleaved scans, since the RPC queue will be ordered and processed on a > FIFO basis. For example, if there are two clients, A & B that submit largish > scans at the same time. Say each scan is broken down into 100 scans by the > client (broken down into equal depth chunks along the row key), and the 100 > scans of client A are queued first, followed immediately by the 100 scans of > client B. In this case, client B will be starved out of getting any results > back until the scans for client A complete. > One solution to this is to use the attached AbstractRoundRobinQueue instead > of the standard FIFO queue. The queue to be used could be (maybe it already > is) configurable based on a new config parameter. Using this queue would > require the client to have the same identifier for all of the 100 parallel > scans that represent a single logical scan from the clients point of view. > With this information, the round robin queue would pick off a task from the > queue in a round robin fashion (instead of a strictly FIFO manner) to prevent > starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Andrew Purtell updated HBASE-12790: --- Status: Open (was: Patch Available) > Support fairness across parallelized scans > -- > > Key: HBASE-12790 > URL: https://issues.apache.org/jira/browse/HBASE-12790 > Project: HBase > Issue Type: New Feature >Reporter: James Taylor >Assignee: ramkrishna.s.vasudevan >Priority: Major > Labels: Phoenix > Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, > HBASE-12790_1.patch, HBASE-12790_5.patch, HBASE-12790_callwrapper.patch, > HBASE-12790_trunk_1.patch, PHOENIX_4.5.3-HBase-0.98-2317-SNAPSHOT.zip > > > Some HBase clients parallelize the execution of a scan to reduce latency in > getting back results. This can lead to starvation with a loaded cluster and > interleaved scans, since the RPC queue will be ordered and processed on a > FIFO basis. For example, if there are two clients, A & B that submit largish > scans at the same time. Say each scan is broken down into 100 scans by the > client (broken down into equal depth chunks along the row key), and the 100 > scans of client A are queued first, followed immediately by the 100 scans of > client B. In this case, client B will be starved out of getting any results > back until the scans for client A complete. > One solution to this is to use the attached AbstractRoundRobinQueue instead > of the standard FIFO queue. The queue to be used could be (maybe it already > is) configurable based on a new config parameter. Using this queue would > require the client to have the same identifier for all of the 100 parallel > scans that represent a single logical scan from the clients point of view. > With this information, the round robin queue would pick off a task from the > queue in a round robin fashion (instead of a strictly FIFO manner) to prevent > starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v7.6.3#76005)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Andrew Purtell updated HBASE-12790: --- Attachment: PHOENIX_4.5.3-HBase-0.98-2317-SNAPSHOT.zip In the interest of moving this forward we asked the perf guys on our Phoenix team to test HBase 0.98.16-SNAPSHOT plus HBASE-12790 and Phoenix 4.5.3-SNAPSHOT with a small patch that allows it to take advantage of the new Scan#getGroupingId API. The server side configuration was updated to specify RoundRobinRPCScheduler for RPC scheduling. The comparison results are attached as "PHOENIX_4.5.3-HBase-0.98-2317-SNAPSHOT.zip" It's an indirect result in that we are viewing perf through the Phoenix lens, but I'm happy to report there are no perf regressions found, only improvements. Therefore I have no concerns in that regard about getting this committed. I put up some comments on https://reviews.apache.org/r/32447. Getting there. /cc [~jamestaylor] > Support fairness across parallelized scans > -- > > Key: HBASE-12790 > URL: https://issues.apache.org/jira/browse/HBASE-12790 > Project: HBase > Issue Type: New Feature >Reporter: James Taylor >Assignee: ramkrishna.s.vasudevan > Labels: Phoenix > Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, > HBASE-12790_1.patch, HBASE-12790_5.patch, HBASE-12790_callwrapper.patch, > HBASE-12790_trunk_1.patch, PHOENIX_4.5.3-HBase-0.98-2317-SNAPSHOT.zip > > > Some HBase clients parallelize the execution of a scan to reduce latency in > getting back results. This can lead to starvation with a loaded cluster and > interleaved scans, since the RPC queue will be ordered and processed on a > FIFO basis. For example, if there are two clients, A & B that submit largish > scans at the same time. Say each scan is broken down into 100 scans by the > client (broken down into equal depth chunks along the row key), and the 100 > scans of client A are queued first, followed immediately by the 100 scans of > client B. In this case, client B will be starved out of getting any results > back until the scans for client A complete. > One solution to this is to use the attached AbstractRoundRobinQueue instead > of the standard FIFO queue. The queue to be used could be (maybe it already > is) configurable based on a new config parameter. Using this queue would > require the client to have the same identifier for all of the 100 parallel > scans that represent a single logical scan from the clients point of view. > With this information, the round robin queue would pick off a task from the > queue in a round robin fashion (instead of a strictly FIFO manner) to prevent > starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] ramkrishna.s.vasudevan updated HBASE-12790: --- Status: Open (was: Patch Available) > Support fairness across parallelized scans > -- > > Key: HBASE-12790 > URL: https://issues.apache.org/jira/browse/HBASE-12790 > Project: HBase > Issue Type: New Feature >Reporter: James Taylor >Assignee: ramkrishna.s.vasudevan > Labels: Phoenix > Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, > HBASE-12790_1.patch, HBASE-12790_5.patch, HBASE-12790_callwrapper.patch > > > Some HBase clients parallelize the execution of a scan to reduce latency in > getting back results. This can lead to starvation with a loaded cluster and > interleaved scans, since the RPC queue will be ordered and processed on a > FIFO basis. For example, if there are two clients, A & B that submit largish > scans at the same time. Say each scan is broken down into 100 scans by the > client (broken down into equal depth chunks along the row key), and the 100 > scans of client A are queued first, followed immediately by the 100 scans of > client B. In this case, client B will be starved out of getting any results > back until the scans for client A complete. > One solution to this is to use the attached AbstractRoundRobinQueue instead > of the standard FIFO queue. The queue to be used could be (maybe it already > is) configurable based on a new config parameter. Using this queue would > require the client to have the same identifier for all of the 100 parallel > scans that represent a single logical scan from the clients point of view. > With this information, the round robin queue would pick off a task from the > queue in a round robin fashion (instead of a strictly FIFO manner) to prevent > starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] ramkrishna.s.vasudevan updated HBASE-12790: --- Attachment: HBASE-12790_trunk_1.patch Patch for trunk. > Support fairness across parallelized scans > -- > > Key: HBASE-12790 > URL: https://issues.apache.org/jira/browse/HBASE-12790 > Project: HBase > Issue Type: New Feature >Reporter: James Taylor >Assignee: ramkrishna.s.vasudevan > Labels: Phoenix > Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, > HBASE-12790_1.patch, HBASE-12790_5.patch, HBASE-12790_callwrapper.patch, > HBASE-12790_trunk_1.patch > > > Some HBase clients parallelize the execution of a scan to reduce latency in > getting back results. This can lead to starvation with a loaded cluster and > interleaved scans, since the RPC queue will be ordered and processed on a > FIFO basis. For example, if there are two clients, A & B that submit largish > scans at the same time. Say each scan is broken down into 100 scans by the > client (broken down into equal depth chunks along the row key), and the 100 > scans of client A are queued first, followed immediately by the 100 scans of > client B. In this case, client B will be starved out of getting any results > back until the scans for client A complete. > One solution to this is to use the attached AbstractRoundRobinQueue instead > of the standard FIFO queue. The queue to be used could be (maybe it already > is) configurable based on a new config parameter. Using this queue would > require the client to have the same identifier for all of the 100 parallel > scans that represent a single logical scan from the clients point of view. > With this information, the round robin queue would pick off a task from the > queue in a round robin fashion (instead of a strictly FIFO manner) to prevent > starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] ramkrishna.s.vasudevan updated HBASE-12790: --- Status: Patch Available (was: Open) > Support fairness across parallelized scans > -- > > Key: HBASE-12790 > URL: https://issues.apache.org/jira/browse/HBASE-12790 > Project: HBase > Issue Type: New Feature >Reporter: James Taylor >Assignee: ramkrishna.s.vasudevan > Labels: Phoenix > Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, > HBASE-12790_1.patch, HBASE-12790_5.patch, HBASE-12790_callwrapper.patch, > HBASE-12790_trunk_1.patch > > > Some HBase clients parallelize the execution of a scan to reduce latency in > getting back results. This can lead to starvation with a loaded cluster and > interleaved scans, since the RPC queue will be ordered and processed on a > FIFO basis. For example, if there are two clients, A & B that submit largish > scans at the same time. Say each scan is broken down into 100 scans by the > client (broken down into equal depth chunks along the row key), and the 100 > scans of client A are queued first, followed immediately by the 100 scans of > client B. In this case, client B will be starved out of getting any results > back until the scans for client A complete. > One solution to this is to use the attached AbstractRoundRobinQueue instead > of the standard FIFO queue. The queue to be used could be (maybe it already > is) configurable based on a new config parameter. Using this queue would > require the client to have the same identifier for all of the 100 parallel > scans that represent a single logical scan from the clients point of view. > With this information, the round robin queue would pick off a task from the > queue in a round robin fashion (instead of a strictly FIFO manner) to prevent > starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] ramkrishna.s.vasudevan updated HBASE-12790: --- Attachment: HBASE-12790_5.patch > Support fairness across parallelized scans > -- > > Key: HBASE-12790 > URL: https://issues.apache.org/jira/browse/HBASE-12790 > Project: HBase > Issue Type: New Feature >Reporter: James Taylor >Assignee: ramkrishna.s.vasudevan > Labels: Phoenix > Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, > HBASE-12790_1.patch, HBASE-12790_5.patch, HBASE-12790_callwrapper.patch > > > Some HBase clients parallelize the execution of a scan to reduce latency in > getting back results. This can lead to starvation with a loaded cluster and > interleaved scans, since the RPC queue will be ordered and processed on a > FIFO basis. For example, if there are two clients, A & B that submit largish > scans at the same time. Say each scan is broken down into 100 scans by the > client (broken down into equal depth chunks along the row key), and the 100 > scans of client A are queued first, followed immediately by the 100 scans of > client B. In this case, client B will be starved out of getting any results > back until the scans for client A complete. > One solution to this is to use the attached AbstractRoundRobinQueue instead > of the standard FIFO queue. The queue to be used could be (maybe it already > is) configurable based on a new config parameter. Using this queue would > require the client to have the same identifier for all of the 100 parallel > scans that represent a single logical scan from the clients point of view. > With this information, the round robin queue would pick off a task from the > queue in a round robin fashion (instead of a strictly FIFO manner) to prevent > starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] ramkrishna.s.vasudevan updated HBASE-12790: --- Status: Patch Available (was: Open) > Support fairness across parallelized scans > -- > > Key: HBASE-12790 > URL: https://issues.apache.org/jira/browse/HBASE-12790 > Project: HBase > Issue Type: New Feature >Reporter: James Taylor >Assignee: ramkrishna.s.vasudevan > Labels: Phoenix > Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, > HBASE-12790_1.patch, HBASE-12790_5.patch, HBASE-12790_callwrapper.patch > > > Some HBase clients parallelize the execution of a scan to reduce latency in > getting back results. This can lead to starvation with a loaded cluster and > interleaved scans, since the RPC queue will be ordered and processed on a > FIFO basis. For example, if there are two clients, A & B that submit largish > scans at the same time. Say each scan is broken down into 100 scans by the > client (broken down into equal depth chunks along the row key), and the 100 > scans of client A are queued first, followed immediately by the 100 scans of > client B. In this case, client B will be starved out of getting any results > back until the scans for client A complete. > One solution to this is to use the attached AbstractRoundRobinQueue instead > of the standard FIFO queue. The queue to be used could be (maybe it already > is) configurable based on a new config parameter. Using this queue would > require the client to have the same identifier for all of the 100 parallel > scans that represent a single logical scan from the clients point of view. > With this information, the round robin queue would pick off a task from the > queue in a round robin fashion (instead of a strictly FIFO manner) to prevent > starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] ramkrishna.s.vasudevan updated HBASE-12790: --- Status: Open (was: Patch Available) Support fairness across parallelized scans -- Key: HBASE-12790 URL: https://issues.apache.org/jira/browse/HBASE-12790 Project: HBase Issue Type: New Feature Reporter: James Taylor Assignee: ramkrishna.s.vasudevan Labels: Phoenix Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, HBASE-12790_1.patch Some HBase clients parallelize the execution of a scan to reduce latency in getting back results. This can lead to starvation with a loaded cluster and interleaved scans, since the RPC queue will be ordered and processed on a FIFO basis. For example, if there are two clients, A B that submit largish scans at the same time. Say each scan is broken down into 100 scans by the client (broken down into equal depth chunks along the row key), and the 100 scans of client A are queued first, followed immediately by the 100 scans of client B. In this case, client B will be starved out of getting any results back until the scans for client A complete. One solution to this is to use the attached AbstractRoundRobinQueue instead of the standard FIFO queue. The queue to be used could be (maybe it already is) configurable based on a new config parameter. Using this queue would require the client to have the same identifier for all of the 100 parallel scans that represent a single logical scan from the clients point of view. With this information, the round robin queue would pick off a task from the queue in a round robin fashion (instead of a strictly FIFO manner) to prevent starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] ramkrishna.s.vasudevan updated HBASE-12790: --- Attachment: HBASE-12790_callwrapper.patch Attaching a patch that has been tested in real cluster. Am working on taking the performance numbers for scans. Currently this patch implements the round robin thing only for scans. Am not very clear on how to write a generic test case. Any suggestions in this area? But pls take note of the following changes, The RpcExecutor and the related Queue data structures will no longer work on CallRunner instead they will work on CallRunnerWrapper. (better name?). This is because CallRunner every time depends on the 'call' object to determine its deadline when we use Deadline based comparator. But since the 'call' can be nullified every time, the new data structure like AbstractPriorityRoundRobinQueue (Using TreeMap) suffers from NPE because of this nullification when it tries to apply the comparison. Also with this patch we calculate the deadline once when the 'call' starts and not every time. We ensure that we no longer depend on the 'call' object to know the deadline for comparisons. You could see that CallPriorityComparator has been removed. Support fairness across parallelized scans -- Key: HBASE-12790 URL: https://issues.apache.org/jira/browse/HBASE-12790 Project: HBase Issue Type: New Feature Reporter: James Taylor Assignee: ramkrishna.s.vasudevan Labels: Phoenix Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, HBASE-12790_1.patch, HBASE-12790_callwrapper.patch Some HBase clients parallelize the execution of a scan to reduce latency in getting back results. This can lead to starvation with a loaded cluster and interleaved scans, since the RPC queue will be ordered and processed on a FIFO basis. For example, if there are two clients, A B that submit largish scans at the same time. Say each scan is broken down into 100 scans by the client (broken down into equal depth chunks along the row key), and the 100 scans of client A are queued first, followed immediately by the 100 scans of client B. In this case, client B will be starved out of getting any results back until the scans for client A complete. One solution to this is to use the attached AbstractRoundRobinQueue instead of the standard FIFO queue. The queue to be used could be (maybe it already is) configurable based on a new config parameter. Using this queue would require the client to have the same identifier for all of the 100 parallel scans that represent a single logical scan from the clients point of view. With this information, the round robin queue would pick off a task from the queue in a round robin fashion (instead of a strictly FIFO manner) to prevent starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] ramkrishna.s.vasudevan updated HBASE-12790: --- Status: Patch Available (was: Open) Support fairness across parallelized scans -- Key: HBASE-12790 URL: https://issues.apache.org/jira/browse/HBASE-12790 Project: HBase Issue Type: New Feature Reporter: James Taylor Labels: Phoenix Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, HBASE-12790_1.patch Some HBase clients parallelize the execution of a scan to reduce latency in getting back results. This can lead to starvation with a loaded cluster and interleaved scans, since the RPC queue will be ordered and processed on a FIFO basis. For example, if there are two clients, A B that submit largish scans at the same time. Say each scan is broken down into 100 scans by the client (broken down into equal depth chunks along the row key), and the 100 scans of client A are queued first, followed immediately by the 100 scans of client B. In this case, client B will be starved out of getting any results back until the scans for client A complete. One solution to this is to use the attached AbstractRoundRobinQueue instead of the standard FIFO queue. The queue to be used could be (maybe it already is) configurable based on a new config parameter. Using this queue would require the client to have the same identifier for all of the 100 parallel scans that represent a single logical scan from the clients point of view. With this information, the round robin queue would pick off a task from the queue in a round robin fashion (instead of a strictly FIFO manner) to prevent starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] ramkrishna.s.vasudevan updated HBASE-12790: --- Attachment: HBASE-12790_1.patch Updated patch with test case. The round robin nature for the AbstractRoundRobinQueue has been corrected as in the first patch we were using one producer under a given priority and once it was over was moving over to the next producer. Which means under Priority A if we had two groups A and B each with 10 task, then we were consuming all the 10 tasks under A and then moving on to B. With the latest patch we ensure that we round robin between the task in A and B. Support fairness across parallelized scans -- Key: HBASE-12790 URL: https://issues.apache.org/jira/browse/HBASE-12790 Project: HBase Issue Type: New Feature Reporter: James Taylor Labels: Phoenix Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch, HBASE-12790_1.patch Some HBase clients parallelize the execution of a scan to reduce latency in getting back results. This can lead to starvation with a loaded cluster and interleaved scans, since the RPC queue will be ordered and processed on a FIFO basis. For example, if there are two clients, A B that submit largish scans at the same time. Say each scan is broken down into 100 scans by the client (broken down into equal depth chunks along the row key), and the 100 scans of client A are queued first, followed immediately by the 100 scans of client B. In this case, client B will be starved out of getting any results back until the scans for client A complete. One solution to this is to use the attached AbstractRoundRobinQueue instead of the standard FIFO queue. The queue to be used could be (maybe it already is) configurable based on a new config parameter. Using this queue would require the client to have the same identifier for all of the 100 parallel scans that represent a single logical scan from the clients point of view. With this information, the round robin queue would pick off a task from the queue in a round robin fashion (instead of a strictly FIFO manner) to prevent starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] ramkrishna.s.vasudevan updated HBASE-12790: --- Attachment: HBASE-12790.patch Support fairness across parallelized scans -- Key: HBASE-12790 URL: https://issues.apache.org/jira/browse/HBASE-12790 Project: HBase Issue Type: New Feature Reporter: James Taylor Labels: Phoenix Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch Some HBase clients parallelize the execution of a scan to reduce latency in getting back results. This can lead to starvation with a loaded cluster and interleaved scans, since the RPC queue will be ordered and processed on a FIFO basis. For example, if there are two clients, A B that submit largish scans at the same time. Say each scan is broken down into 100 scans by the client (broken down into equal depth chunks along the row key), and the 100 scans of client A are queued first, followed immediately by the 100 scans of client B. In this case, client B will be starved out of getting any results back until the scans for client A complete. One solution to this is to use the attached AbstractRoundRobinQueue instead of the standard FIFO queue. The queue to be used could be (maybe it already is) configurable based on a new config parameter. Using this queue would require the client to have the same identifier for all of the 100 parallel scans that represent a single logical scan from the clients point of view. With this information, the round robin queue would pick off a task from the queue in a round robin fashion (instead of a strictly FIFO manner) to prevent starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] James Taylor updated HBASE-12790: - Issue Type: New Feature (was: Bug) Support fairness across parallelized scans -- Key: HBASE-12790 URL: https://issues.apache.org/jira/browse/HBASE-12790 Project: HBase Issue Type: New Feature Reporter: James Taylor Labels: Phoenix Attachments: AbstractRoundRobinQueue.java Some HBase clients parallelize the execution of a scan to reduce latency in getting back results. This can lead to starvation with a loaded cluster and interleaved scans, since the RPC queue will be ordered and processed on a FIFO basis. For example, if there are two clients, A B that submit largish scans at the same time. Say each scan is broken down into 100 scans by the client (broken down into equal depth chunks along the row key), and the 100 scans of client A are queued first, followed immediately by the 100 scans of client B. In this case, client B will be starved out of getting any results back until the scans for client A complete. One solution to this is to use the attached AbstractRoundRobinQueue instead of the standard FIFO queue. The queue to be used could be (maybe it already is) configurable based on a new config parameter. Using this queue would require the client to have the same identifier for all of the 100 parallel scans that represent a single logical scan from the clients point of view. With this information, the round robin queue would pick off a task from the queue in a round robin fashion (instead of a strictly FIFO manner) to prevent starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Updated] (HBASE-12790) Support fairness across parallelized scans
[ https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] James Taylor updated HBASE-12790: - Attachment: AbstractRoundRobinQueue.java Alternate round-robin based-queue implementation for ThreadPoolExecutor Support fairness across parallelized scans -- Key: HBASE-12790 URL: https://issues.apache.org/jira/browse/HBASE-12790 Project: HBase Issue Type: Bug Reporter: James Taylor Labels: Phoenix Attachments: AbstractRoundRobinQueue.java Some HBase clients parallelize the execution of a scan to reduce latency in getting back results. This can lead to starvation with a loaded cluster and interleaved scans, since the RPC queue will be ordered and processed on a FIFO basis. For example, if there are two clients, A B that submit largish scans at the same time. Say each scan is broken down into 100 scans by the client (broken down into equal depth chunks along the row key), and the 100 scans of client A are queued first, followed immediately by the 100 scans of client B. In this case, client B will be starved out of getting any results back until the scans for client A complete. One solution to this is to use the attached AbstractRoundRobinQueue instead of the standard FIFO queue. The queue to be used could be (maybe it already is) configurable based on a new config parameter. Using this queue would require the client to have the same identifier for all of the 100 parallel scans that represent a single logical scan from the clients point of view. With this information, the round robin queue would pick off a task from the queue in a round robin fashion (instead of a strictly FIFO manner) to prevent starvation over interleaved parallelized scans. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
