[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2020-02-19 Thread Benedict Elliott Smith (Jira)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Benedict Elliott Smith updated CASSANDRA-15213:
---
Since Version: 4.0-alpha  (was: 4.0)

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict Elliott Smith
>Assignee: Jordan West
>Priority: Normal
> Fix For: 4.0-beta
>
> Attachments: 15213-perf-branch, 15213-perf-trunk
>
>
> * {{LongAdder}} introduced to trunk consumes 9MiB of heap without user 
> schemas, and this will grow significantly under contention and user schemas 
> with many tables.  This is because {{LongAdder}} is a very heavy class 
> designed for single contended values.  
>  ** This can likely be improved significantly, without significant loss of 
> performance in the contended case, by simply increasing the size of our 
> primitive backing array and providing multiple buckets, with each thread 
> picking a bucket to increment, or simply multiple backing arrays.  Probably a 
> better way still to do this would be to introduce some competition detection 
> to the update, much like {{LongAdder}} utilises, that increases the number of 
> backing arrays under competition.
>  ** To save memory this approach could partition the space into chunks that 
> are likely to be updated together, so that we do not need to duplicate the 
> entire array under competition.
>  * Similarly, binary search is costly and a measurable cost as a share of the 
> new networking work (without filtering it was > 10% of the CPU used overall). 
>  We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, 
> to save the random memory access costs.



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[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2020-02-19 Thread Benedict Elliott Smith (Jira)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Benedict Elliott Smith updated CASSANDRA-15213:
---
  Since Version: 4.0
Source Control Link: 
[adc3cdde2ae2a78f7d2bb66da47a07545d3e06cf|https://github.com/apache/cassandra/commit/adc3cdde2ae2a78f7d2bb66da47a07545d3e06cf]
 Resolution: Fixed
 Status: Resolved  (was: Ready to Commit)

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict Elliott Smith
>Assignee: Jordan West
>Priority: Normal
> Fix For: 4.0-beta
>
> Attachments: 15213-perf-branch, 15213-perf-trunk
>
>
> * {{LongAdder}} introduced to trunk consumes 9MiB of heap without user 
> schemas, and this will grow significantly under contention and user schemas 
> with many tables.  This is because {{LongAdder}} is a very heavy class 
> designed for single contended values.  
>  ** This can likely be improved significantly, without significant loss of 
> performance in the contended case, by simply increasing the size of our 
> primitive backing array and providing multiple buckets, with each thread 
> picking a bucket to increment, or simply multiple backing arrays.  Probably a 
> better way still to do this would be to introduce some competition detection 
> to the update, much like {{LongAdder}} utilises, that increases the number of 
> backing arrays under competition.
>  ** To save memory this approach could partition the space into chunks that 
> are likely to be updated together, so that we do not need to duplicate the 
> entire array under competition.
>  * Similarly, binary search is costly and a measurable cost as a share of the 
> new networking work (without filtering it was > 10% of the CPU used overall). 
>  We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, 
> to save the random memory access costs.



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[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2020-02-19 Thread Benedict Elliott Smith (Jira)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Benedict Elliott Smith updated CASSANDRA-15213:
---
Fix Version/s: 4.0

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict Elliott Smith
>Assignee: Jordan West
>Priority: Normal
> Fix For: 4.0, 4.0-beta
>
> Attachments: 15213-perf-branch, 15213-perf-trunk
>
>
> * {{LongAdder}} introduced to trunk consumes 9MiB of heap without user 
> schemas, and this will grow significantly under contention and user schemas 
> with many tables.  This is because {{LongAdder}} is a very heavy class 
> designed for single contended values.  
>  ** This can likely be improved significantly, without significant loss of 
> performance in the contended case, by simply increasing the size of our 
> primitive backing array and providing multiple buckets, with each thread 
> picking a bucket to increment, or simply multiple backing arrays.  Probably a 
> better way still to do this would be to introduce some competition detection 
> to the update, much like {{LongAdder}} utilises, that increases the number of 
> backing arrays under competition.
>  ** To save memory this approach could partition the space into chunks that 
> are likely to be updated together, so that we do not need to duplicate the 
> entire array under competition.
>  * Similarly, binary search is costly and a measurable cost as a share of the 
> new networking work (without filtering it was > 10% of the CPU used overall). 
>  We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, 
> to save the random memory access costs.



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[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2020-02-18 Thread Jordan West (Jira)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Jordan West updated CASSANDRA-15213:

Status: Ready to Commit  (was: Review In Progress)

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict Elliott Smith
>Assignee: Jordan West
>Priority: Normal
> Fix For: 4.0-beta
>
> Attachments: 15213-perf-branch, 15213-perf-trunk
>
>
> * {{LongAdder}} introduced to trunk consumes 9MiB of heap without user 
> schemas, and this will grow significantly under contention and user schemas 
> with many tables.  This is because {{LongAdder}} is a very heavy class 
> designed for single contended values.  
>  ** This can likely be improved significantly, without significant loss of 
> performance in the contended case, by simply increasing the size of our 
> primitive backing array and providing multiple buckets, with each thread 
> picking a bucket to increment, or simply multiple backing arrays.  Probably a 
> better way still to do this would be to introduce some competition detection 
> to the update, much like {{LongAdder}} utilises, that increases the number of 
> backing arrays under competition.
>  ** To save memory this approach could partition the space into chunks that 
> are likely to be updated together, so that we do not need to duplicate the 
> entire array under competition.
>  * Similarly, binary search is costly and a measurable cost as a share of the 
> new networking work (without filtering it was > 10% of the CPU used overall). 
>  We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, 
> to save the random memory access costs.



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[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2020-02-18 Thread Jordan West (Jira)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Jordan West updated CASSANDRA-15213:

Test and Documentation Plan: Existing microbenchmarks, new cluster 
benchmarks, quick theories tests
 Status: Patch Available  (was: Open)

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict Elliott Smith
>Assignee: Jordan West
>Priority: Normal
> Fix For: 4.0-beta
>
> Attachments: 15213-perf-branch, 15213-perf-trunk
>
>
> * {{LongAdder}} introduced to trunk consumes 9MiB of heap without user 
> schemas, and this will grow significantly under contention and user schemas 
> with many tables.  This is because {{LongAdder}} is a very heavy class 
> designed for single contended values.  
>  ** This can likely be improved significantly, without significant loss of 
> performance in the contended case, by simply increasing the size of our 
> primitive backing array and providing multiple buckets, with each thread 
> picking a bucket to increment, or simply multiple backing arrays.  Probably a 
> better way still to do this would be to introduce some competition detection 
> to the update, much like {{LongAdder}} utilises, that increases the number of 
> backing arrays under competition.
>  ** To save memory this approach could partition the space into chunks that 
> are likely to be updated together, so that we do not need to duplicate the 
> entire array under competition.
>  * Similarly, binary search is costly and a measurable cost as a share of the 
> new networking work (without filtering it was > 10% of the CPU used overall). 
>  We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, 
> to save the random memory access costs.



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[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2020-02-18 Thread Jordan West (Jira)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Jordan West updated CASSANDRA-15213:

Reviewers: Benedict Elliott Smith, Jordan West  (was: Chris Lohfink)
   Status: Review In Progress  (was: Patch Available)

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict Elliott Smith
>Assignee: Jordan West
>Priority: Normal
> Fix For: 4.0-beta
>
> Attachments: 15213-perf-branch, 15213-perf-trunk
>
>
> * {{LongAdder}} introduced to trunk consumes 9MiB of heap without user 
> schemas, and this will grow significantly under contention and user schemas 
> with many tables.  This is because {{LongAdder}} is a very heavy class 
> designed for single contended values.  
>  ** This can likely be improved significantly, without significant loss of 
> performance in the contended case, by simply increasing the size of our 
> primitive backing array and providing multiple buckets, with each thread 
> picking a bucket to increment, or simply multiple backing arrays.  Probably a 
> better way still to do this would be to introduce some competition detection 
> to the update, much like {{LongAdder}} utilises, that increases the number of 
> backing arrays under competition.
>  ** To save memory this approach could partition the space into chunks that 
> are likely to be updated together, so that we do not need to duplicate the 
> entire array under competition.
>  * Similarly, binary search is costly and a measurable cost as a share of the 
> new networking work (without filtering it was > 10% of the CPU used overall). 
>  We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, 
> to save the random memory access costs.



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[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2020-02-06 Thread Jordan West (Jira)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Jordan West updated CASSANDRA-15213:

Attachment: 15213-perf-trunk
15213-perf-branch

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict Elliott Smith
>Assignee: Jordan West
>Priority: Normal
> Fix For: 4.0-beta
>
> Attachments: 15213-perf-branch, 15213-perf-trunk
>
>
> * {{LongAdder}} introduced to trunk consumes 9MiB of heap without user 
> schemas, and this will grow significantly under contention and user schemas 
> with many tables.  This is because {{LongAdder}} is a very heavy class 
> designed for single contended values.  
>  ** This can likely be improved significantly, without significant loss of 
> performance in the contended case, by simply increasing the size of our 
> primitive backing array and providing multiple buckets, with each thread 
> picking a bucket to increment, or simply multiple backing arrays.  Probably a 
> better way still to do this would be to introduce some competition detection 
> to the update, much like {{LongAdder}} utilises, that increases the number of 
> backing arrays under competition.
>  ** To save memory this approach could partition the space into chunks that 
> are likely to be updated together, so that we do not need to duplicate the 
> entire array under competition.
>  * Similarly, binary search is costly and a measurable cost as a share of the 
> new networking work (without filtering it was > 10% of the CPU used overall). 
>  We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, 
> to save the random memory access costs.



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[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2019-08-29 Thread Benedict (Jira)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Benedict updated CASSANDRA-15213:
-
Fix Version/s: (was: 4.0)
   4.0-beta

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict
>Priority: Normal
> Fix For: 4.0-beta
>
>
> * {{LongAdder}} introduced to trunk consumes 9MiB of heap without user 
> schemas, and this will grow significantly under contention and user schemas 
> with many tables.  This is because {{LongAdder}} is a very heavy class 
> designed for single contended values.  
>  ** This can likely be improved significantly, without significant loss of 
> performance in the contended case, by simply increasing the size of our 
> primitive backing array and providing multiple buckets, with each thread 
> picking a bucket to increment, or simply multiple backing arrays.  Probably a 
> better way still to do this would be to introduce some competition detection 
> to the update, much like {{LongAdder}} utilises, that increases the number of 
> backing arrays under competition.
>  ** To save memory this approach could partition the space into chunks that 
> are likely to be updated together, so that we do not need to duplicate the 
> entire array under competition.
>  * Similarly, binary search is costly and a measurable cost as a share of the 
> new networking work (without filtering it was > 10% of the CPU used overall). 
>  We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, 
> to save the random memory access costs.



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[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2019-07-16 Thread Chris Lohfink (JIRA)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Chris Lohfink updated CASSANDRA-15213:
--
Reviewers: Chris Lohfink

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict
>Priority: Normal
> Fix For: 4.0
>
>
> * {{LongAdder}} introduced to trunk consumes 9MiB of heap without user 
> schemas, and this will grow significantly under contention and user schemas 
> with many tables.  This is because {{LongAdder}} is a very heavy class 
> designed for single contended values.  
>  ** This can likely be improved significantly, without significant loss of 
> performance in the contended case, by simply increasing the size of our 
> primitive backing array and providing multiple buckets, with each thread 
> picking a bucket to increment, or simply multiple backing arrays.  Probably a 
> better way still to do this would be to introduce some competition detection 
> to the update, much like {{LongAdder}} utilises, that increases the number of 
> backing arrays under competition.
>  ** To save memory this approach could partition the space into chunks that 
> are likely to be updated together, so that we do not need to duplicate the 
> entire array under competition.
>  * Similarly, binary search is costly and a measurable cost as a share of the 
> new networking work (without filtering it was > 10% of the CPU used overall). 
>  We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, 
> to save the random memory access costs.



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[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2019-07-16 Thread Benedict (JIRA)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Benedict updated CASSANDRA-15213:
-
Fix Version/s: 4.0

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict
>Priority: Normal
> Fix For: 4.0
>
>
> * {{LongAdder}} introduced to trunk consumes 9MiB of heap without user 
> schemas, and this will grow significantly under contention and user schemas 
> with many tables.  This is because {{LongAdder}} is a very heavy class 
> designed for single contended values.  
>  ** This can likely be improved significantly, without significant loss of 
> performance in the contended case, by simply increasing the size of our 
> primitive backing array and providing multiple buckets, with each thread 
> picking a bucket to increment, or simply multiple backing arrays.  Probably a 
> better way still to do this would be to introduce some competition detection 
> to the update, much like {{LongAdder}} utilises, that increases the number of 
> backing arrays under competition.
>  ** To save memory this approach could partition the space into chunks that 
> are likely to be updated together, so that we do not need to duplicate the 
> entire array under competition.
>  * Similarly, binary search is costly and a measurable cost as a share of the 
> new networking work (without filtering it was > 10% of the CPU used overall). 
>  We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, 
> to save the random memory access costs.



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[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2019-07-16 Thread Benedict (JIRA)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Benedict updated CASSANDRA-15213:
-
Description: 
* {{LongAdder}} introduced to trunk consumes 9MiB of heap without user schemas, 
and this will grow significantly under contention and user schemas with many 
tables.  This is because {{LongAdder}} is a very heavy class designed for 
single contended values.  
 ** This can likely be improved significantly, without significant loss of 
performance in the contended case, by simply increasing the size of our 
primitive backing array and providing multiple buckets, with each thread 
picking a bucket to increment, or simply multiple backing arrays.  Probably a 
better way still to do this would be to introduce some competition detection to 
the update, much like {{LongAdder}} utilises, that increases the number of 
backing arrays under competition.
 ** To save memory this approach could partition the space into chunks that are 
likely to be updated together, so that we do not need to duplicate the entire 
array under competition.
 * Similarly, binary search is costly and a measurable cost as a share of the 
new networking work (without filtering it was > 10% of the CPU used overall).  
We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, to 
save the random memory access costs.

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict
>Priority: Normal
>
> * {{LongAdder}} introduced to trunk consumes 9MiB of heap without user 
> schemas, and this will grow significantly under contention and user schemas 
> with many tables.  This is because {{LongAdder}} is a very heavy class 
> designed for single contended values.  
>  ** This can likely be improved significantly, without significant loss of 
> performance in the contended case, by simply increasing the size of our 
> primitive backing array and providing multiple buckets, with each thread 
> picking a bucket to increment, or simply multiple backing arrays.  Probably a 
> better way still to do this would be to introduce some competition detection 
> to the update, much like {{LongAdder}} utilises, that increases the number of 
> backing arrays under competition.
>  ** To save memory this approach could partition the space into chunks that 
> are likely to be updated together, so that we do not need to duplicate the 
> entire array under competition.
>  * Similarly, binary search is costly and a measurable cost as a share of the 
> new networking work (without filtering it was > 10% of the CPU used overall). 
>  We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, 
> to save the random memory access costs.



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[jira] [Updated] (CASSANDRA-15213) DecayingEstimatedHistogramReservoir Inefficiencies

2019-07-16 Thread Benedict (JIRA)


 [ 
https://issues.apache.org/jira/browse/CASSANDRA-15213?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Benedict updated CASSANDRA-15213:
-
 Severity: Low
   Complexity: Normal
Discovered By: Adhoc Test
 Bug Category: Parent values: Degradation(12984)Level 1 values: Performance 
Bug/Regression(12997)
  Component/s: Observability/Metrics
   Status: Open  (was: Triage Needed)

* {{LongAdder}} introduced to trunk consumes 9MiB of heap without user schemas, 
and this will grow significantly under contention and user schemas with many 
tables.  This is because {{LongAdder}} is a very heavy class designed for 
single contended values.  
 ** This can likely be improved significantly, without significant loss of 
performance in the contended case, by simply increasing the size of our 
primitive backing array and providing multiple buckets, with each thread 
picking a bucket to increment, or simply multiple backing arrays.  Probably a 
better way still to do this would be to introduce some competition detection to 
the update, much like {{LongAdder}} utilises, that increases the number of 
backing arrays under competition.
 ** To save memory this approach could partition the space into chunks that are 
likely to be updated together, so that we do not need to duplicate the entire 
array under competition.
 * Similarly, binary search is costly and a measurable cost as a share of the 
new networking work (without filtering it was > 10% of the CPU used overall).  
We can compute an approximation floor(log2 n / log2 1.2) extremely cheaply, to 
save the random memory access costs.

> DecayingEstimatedHistogramReservoir Inefficiencies
> --
>
> Key: CASSANDRA-15213
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15213
> Project: Cassandra
>  Issue Type: Bug
>  Components: Observability/Metrics
>Reporter: Benedict
>Priority: Normal
>




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