[jira] [Updated] (HBASE-24528) Improve balancer decision observability
[ https://issues.apache.org/jira/browse/HBASE-24528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Viraj Jasani updated HBASE-24528: - Attachment: (was: NamedQueue_Framework_Design.pdf) > Improve balancer decision observability > --- > > Key: HBASE-24528 > URL: https://issues.apache.org/jira/browse/HBASE-24528 > Project: HBase > Issue Type: New Feature > Components: Admin, Balancer, Operability, shell, UI >Reporter: Andrew Kyle Purtell >Assignee: Viraj Jasani >Priority: Major > Fix For: 3.0.0-alpha-1, 1.7.0, 2.4.0 > > Attachments: > NamedQueue_Framework_Design_HBASE-24528_HBASE-22978_HBASE-24718.pdf, > Screenshot 2020-08-12 at 11.50.43 PM.png, Screenshot 2020-08-15 at 8.08.57 > PM.png > > > We provide detailed INFO and DEBUG level logging of balancer decision > factors, outcome, and reassignment planning, as well as similarly detailed > logging of the resulting assignment manager activity. However, an operator > may need to perform online and interactive observation, debugging, or > performance analysis of current balancer activity. Scraping and correlating > the many log lines resulting from a balancer execution is labor intensive and > has a lot of latency (order of ~minutes to acquire and index, order of > ~minutes to correlate). > The balancer should maintain a rolling window of history, e.g. the last 100 > region move plans, or last 1000 region move plans submitted to the assignment > manager. This history should include decision factor details and weights and > costs. The rsgroups balancer may be able to provide fairly simple decision > factors, like for example "this table was reassigned to that regionserver > group". The underlying or vanilla stochastic balancer on the other hand, > after a walk over random assignment plans, will have considered a number of > cost functions with various inputs (locality, load, etc.) and multipliers, > including custom cost functions. We can devise an extensible class structure > that represents explanations for balancer decisions, and for each region move > plan that is actually submitted to the assignment manager, we can keep the > explanations of all relevant decision factors alongside the other details of > the assignment plan like the region name, and the source and destination > regionservers. > This history should be available via API for use by new shell commands and > admin UI widgets. > The new shell commands and UI widgets can unpack the representation of > balancer decision components into human readable output. -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Updated] (HBASE-24528) Improve balancer decision observability
[ https://issues.apache.org/jira/browse/HBASE-24528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Viraj Jasani updated HBASE-24528: - Attachment: NamedQueue_Framework_Design_HBASE-24528_HBASE-22978_HBASE-24718.pdf > Improve balancer decision observability > --- > > Key: HBASE-24528 > URL: https://issues.apache.org/jira/browse/HBASE-24528 > Project: HBase > Issue Type: New Feature > Components: Admin, Balancer, Operability, shell, UI >Reporter: Andrew Kyle Purtell >Assignee: Viraj Jasani >Priority: Major > Fix For: 3.0.0-alpha-1, 1.7.0, 2.4.0 > > Attachments: > NamedQueue_Framework_Design_HBASE-24528_HBASE-22978_HBASE-24718.pdf, > Screenshot 2020-08-12 at 11.50.43 PM.png, Screenshot 2020-08-15 at 8.08.57 > PM.png > > > We provide detailed INFO and DEBUG level logging of balancer decision > factors, outcome, and reassignment planning, as well as similarly detailed > logging of the resulting assignment manager activity. However, an operator > may need to perform online and interactive observation, debugging, or > performance analysis of current balancer activity. Scraping and correlating > the many log lines resulting from a balancer execution is labor intensive and > has a lot of latency (order of ~minutes to acquire and index, order of > ~minutes to correlate). > The balancer should maintain a rolling window of history, e.g. the last 100 > region move plans, or last 1000 region move plans submitted to the assignment > manager. This history should include decision factor details and weights and > costs. The rsgroups balancer may be able to provide fairly simple decision > factors, like for example "this table was reassigned to that regionserver > group". The underlying or vanilla stochastic balancer on the other hand, > after a walk over random assignment plans, will have considered a number of > cost functions with various inputs (locality, load, etc.) and multipliers, > including custom cost functions. We can devise an extensible class structure > that represents explanations for balancer decisions, and for each region move > plan that is actually submitted to the assignment manager, we can keep the > explanations of all relevant decision factors alongside the other details of > the assignment plan like the region name, and the source and destination > regionservers. > This history should be available via API for use by new shell commands and > admin UI widgets. > The new shell commands and UI widgets can unpack the representation of > balancer decision components into human readable output. -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Updated] (HBASE-24528) Improve balancer decision observability
[ https://issues.apache.org/jira/browse/HBASE-24528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Viraj Jasani updated HBASE-24528: - Attachment: NamedQueue_Framework_Design.pdf > Improve balancer decision observability > --- > > Key: HBASE-24528 > URL: https://issues.apache.org/jira/browse/HBASE-24528 > Project: HBase > Issue Type: New Feature > Components: Admin, Balancer, Operability, shell, UI >Reporter: Andrew Kyle Purtell >Assignee: Viraj Jasani >Priority: Major > Fix For: 3.0.0-alpha-1, 1.7.0, 2.4.0 > > Attachments: NamedQueue_Framework_Design.pdf, Screenshot 2020-08-12 > at 11.50.43 PM.png, Screenshot 2020-08-15 at 8.08.57 PM.png > > > We provide detailed INFO and DEBUG level logging of balancer decision > factors, outcome, and reassignment planning, as well as similarly detailed > logging of the resulting assignment manager activity. However, an operator > may need to perform online and interactive observation, debugging, or > performance analysis of current balancer activity. Scraping and correlating > the many log lines resulting from a balancer execution is labor intensive and > has a lot of latency (order of ~minutes to acquire and index, order of > ~minutes to correlate). > The balancer should maintain a rolling window of history, e.g. the last 100 > region move plans, or last 1000 region move plans submitted to the assignment > manager. This history should include decision factor details and weights and > costs. The rsgroups balancer may be able to provide fairly simple decision > factors, like for example "this table was reassigned to that regionserver > group". The underlying or vanilla stochastic balancer on the other hand, > after a walk over random assignment plans, will have considered a number of > cost functions with various inputs (locality, load, etc.) and multipliers, > including custom cost functions. We can devise an extensible class structure > that represents explanations for balancer decisions, and for each region move > plan that is actually submitted to the assignment manager, we can keep the > explanations of all relevant decision factors alongside the other details of > the assignment plan like the region name, and the source and destination > regionservers. > This history should be available via API for use by new shell commands and > admin UI widgets. > The new shell commands and UI widgets can unpack the representation of > balancer decision components into human readable output. -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Updated] (HBASE-24528) Improve balancer decision observability
[ https://issues.apache.org/jira/browse/HBASE-24528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Viraj Jasani updated HBASE-24528: - Release Note: Retrieve latest balancer decisions made by LoadBalancers. Examples: hbase> get_balancer_decisions Retrieve recent balancer decisions with region plans hbase> get_balancer_decisions LIMIT => 10 Retrieve 10 most recent balancer decisions with region plans Config change: hbase.master.balancer.decision.buffer.enabled: Indicates whether active HMaster has ring buffer running for storing balancer decisions in FIFO manner with limited entries. The size of the ring buffer is indicated by config: hbase.master.balancer.decision.queue.size was: Retrieve latest balancer decisions made by LoadBalancers. Examples: hbase> get_balancer_decisions => Retrieve recent balancer decisions with region plans hbase> get_balancer_decisions LIMIT => 10 => Retrieve 10 most recent balancer decisions with region plans Config change: hbase.master.balancer.decision.buffer.enabled: Indicates whether active HMaster has ring buffer running for storing balancer decisions in FIFO manner with limited entries. The size of the ring buffer is indicated by config: hbase.master.balancer.decision.queue.size > Improve balancer decision observability > --- > > Key: HBASE-24528 > URL: https://issues.apache.org/jira/browse/HBASE-24528 > Project: HBase > Issue Type: New Feature > Components: Admin, Balancer, Operability, shell, UI >Reporter: Andrew Kyle Purtell >Assignee: Viraj Jasani >Priority: Major > Fix For: 3.0.0-alpha-1, 1.7.0, 2.4.0 > > Attachments: Screenshot 2020-08-12 at 11.50.43 PM.png, Screenshot > 2020-08-15 at 8.08.57 PM.png > > > We provide detailed INFO and DEBUG level logging of balancer decision > factors, outcome, and reassignment planning, as well as similarly detailed > logging of the resulting assignment manager activity. However, an operator > may need to perform online and interactive observation, debugging, or > performance analysis of current balancer activity. Scraping and correlating > the many log lines resulting from a balancer execution is labor intensive and > has a lot of latency (order of ~minutes to acquire and index, order of > ~minutes to correlate). > The balancer should maintain a rolling window of history, e.g. the last 100 > region move plans, or last 1000 region move plans submitted to the assignment > manager. This history should include decision factor details and weights and > costs. The rsgroups balancer may be able to provide fairly simple decision > factors, like for example "this table was reassigned to that regionserver > group". The underlying or vanilla stochastic balancer on the other hand, > after a walk over random assignment plans, will have considered a number of > cost functions with various inputs (locality, load, etc.) and multipliers, > including custom cost functions. We can devise an extensible class structure > that represents explanations for balancer decisions, and for each region move > plan that is actually submitted to the assignment manager, we can keep the > explanations of all relevant decision factors alongside the other details of > the assignment plan like the region name, and the source and destination > regionservers. > This history should be available via API for use by new shell commands and > admin UI widgets. > The new shell commands and UI widgets can unpack the representation of > balancer decision components into human readable output. -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Updated] (HBASE-24528) Improve balancer decision observability
[ https://issues.apache.org/jira/browse/HBASE-24528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Viraj Jasani updated HBASE-24528: - Release Note: Retrieve latest balancer decisions made by LoadBalancers. Examples: hbase> get_balancer_decisions => Retrieve recent balancer decisions with region plans hbase> get_balancer_decisions LIMIT => 10 => Retrieve 10 most recent balancer decisions with region plans Config change: hbase.master.balancer.decision.buffer.enabled: Indicates whether active HMaster has ring buffer running for storing balancer decisions in FIFO manner with limited entries. The size of the ring buffer is indicated by config: hbase.master.balancer.decision.queue.size > Improve balancer decision observability > --- > > Key: HBASE-24528 > URL: https://issues.apache.org/jira/browse/HBASE-24528 > Project: HBase > Issue Type: New Feature > Components: Admin, Balancer, Operability, shell, UI >Reporter: Andrew Kyle Purtell >Assignee: Viraj Jasani >Priority: Major > Fix For: 3.0.0-alpha-1, 1.7.0, 2.4.0 > > Attachments: Screenshot 2020-08-12 at 11.50.43 PM.png, Screenshot > 2020-08-15 at 8.08.57 PM.png > > > We provide detailed INFO and DEBUG level logging of balancer decision > factors, outcome, and reassignment planning, as well as similarly detailed > logging of the resulting assignment manager activity. However, an operator > may need to perform online and interactive observation, debugging, or > performance analysis of current balancer activity. Scraping and correlating > the many log lines resulting from a balancer execution is labor intensive and > has a lot of latency (order of ~minutes to acquire and index, order of > ~minutes to correlate). > The balancer should maintain a rolling window of history, e.g. the last 100 > region move plans, or last 1000 region move plans submitted to the assignment > manager. This history should include decision factor details and weights and > costs. The rsgroups balancer may be able to provide fairly simple decision > factors, like for example "this table was reassigned to that regionserver > group". The underlying or vanilla stochastic balancer on the other hand, > after a walk over random assignment plans, will have considered a number of > cost functions with various inputs (locality, load, etc.) and multipliers, > including custom cost functions. We can devise an extensible class structure > that represents explanations for balancer decisions, and for each region move > plan that is actually submitted to the assignment manager, we can keep the > explanations of all relevant decision factors alongside the other details of > the assignment plan like the region name, and the source and destination > regionservers. > This history should be available via API for use by new shell commands and > admin UI widgets. > The new shell commands and UI widgets can unpack the representation of > balancer decision components into human readable output. -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Updated] (HBASE-24528) Improve balancer decision observability
[ https://issues.apache.org/jira/browse/HBASE-24528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Viraj Jasani updated HBASE-24528: - Hadoop Flags: Reviewed Resolution: Fixed Status: Resolved (was: Patch Available) > Improve balancer decision observability > --- > > Key: HBASE-24528 > URL: https://issues.apache.org/jira/browse/HBASE-24528 > Project: HBase > Issue Type: New Feature > Components: Admin, Balancer, Operability, shell, UI >Reporter: Andrew Kyle Purtell >Assignee: Viraj Jasani >Priority: Major > Fix For: 3.0.0-alpha-1, 1.7.0, 2.4.0 > > Attachments: Screenshot 2020-08-12 at 11.50.43 PM.png, Screenshot > 2020-08-15 at 8.08.57 PM.png > > > We provide detailed INFO and DEBUG level logging of balancer decision > factors, outcome, and reassignment planning, as well as similarly detailed > logging of the resulting assignment manager activity. However, an operator > may need to perform online and interactive observation, debugging, or > performance analysis of current balancer activity. Scraping and correlating > the many log lines resulting from a balancer execution is labor intensive and > has a lot of latency (order of ~minutes to acquire and index, order of > ~minutes to correlate). > The balancer should maintain a rolling window of history, e.g. the last 100 > region move plans, or last 1000 region move plans submitted to the assignment > manager. This history should include decision factor details and weights and > costs. The rsgroups balancer may be able to provide fairly simple decision > factors, like for example "this table was reassigned to that regionserver > group". The underlying or vanilla stochastic balancer on the other hand, > after a walk over random assignment plans, will have considered a number of > cost functions with various inputs (locality, load, etc.) and multipliers, > including custom cost functions. We can devise an extensible class structure > that represents explanations for balancer decisions, and for each region move > plan that is actually submitted to the assignment manager, we can keep the > explanations of all relevant decision factors alongside the other details of > the assignment plan like the region name, and the source and destination > regionservers. > This history should be available via API for use by new shell commands and > admin UI widgets. > The new shell commands and UI widgets can unpack the representation of > balancer decision components into human readable output. -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Updated] (HBASE-24528) Improve balancer decision observability
[ https://issues.apache.org/jira/browse/HBASE-24528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Viraj Jasani updated HBASE-24528: - Fix Version/s: 2.4.0 1.7.0 3.0.0-alpha-1 > Improve balancer decision observability > --- > > Key: HBASE-24528 > URL: https://issues.apache.org/jira/browse/HBASE-24528 > Project: HBase > Issue Type: New Feature > Components: Admin, Balancer, Operability, shell, UI >Reporter: Andrew Kyle Purtell >Assignee: Viraj Jasani >Priority: Major > Fix For: 3.0.0-alpha-1, 1.7.0, 2.4.0 > > Attachments: Screenshot 2020-08-12 at 11.50.43 PM.png, Screenshot > 2020-08-15 at 8.08.57 PM.png > > > We provide detailed INFO and DEBUG level logging of balancer decision > factors, outcome, and reassignment planning, as well as similarly detailed > logging of the resulting assignment manager activity. However, an operator > may need to perform online and interactive observation, debugging, or > performance analysis of current balancer activity. Scraping and correlating > the many log lines resulting from a balancer execution is labor intensive and > has a lot of latency (order of ~minutes to acquire and index, order of > ~minutes to correlate). > The balancer should maintain a rolling window of history, e.g. the last 100 > region move plans, or last 1000 region move plans submitted to the assignment > manager. This history should include decision factor details and weights and > costs. The rsgroups balancer may be able to provide fairly simple decision > factors, like for example "this table was reassigned to that regionserver > group". The underlying or vanilla stochastic balancer on the other hand, > after a walk over random assignment plans, will have considered a number of > cost functions with various inputs (locality, load, etc.) and multipliers, > including custom cost functions. We can devise an extensible class structure > that represents explanations for balancer decisions, and for each region move > plan that is actually submitted to the assignment manager, we can keep the > explanations of all relevant decision factors alongside the other details of > the assignment plan like the region name, and the source and destination > regionservers. > This history should be available via API for use by new shell commands and > admin UI widgets. > The new shell commands and UI widgets can unpack the representation of > balancer decision components into human readable output. -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Updated] (HBASE-24528) Improve balancer decision observability
[ https://issues.apache.org/jira/browse/HBASE-24528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Viraj Jasani updated HBASE-24528: - Status: Patch Available (was: In Progress) > Improve balancer decision observability > --- > > Key: HBASE-24528 > URL: https://issues.apache.org/jira/browse/HBASE-24528 > Project: HBase > Issue Type: New Feature > Components: Admin, Balancer, Operability, shell, UI >Reporter: Andrew Kyle Purtell >Assignee: Viraj Jasani >Priority: Major > Attachments: Screenshot 2020-08-12 at 11.50.43 PM.png, Screenshot > 2020-08-15 at 8.08.57 PM.png > > > We provide detailed INFO and DEBUG level logging of balancer decision > factors, outcome, and reassignment planning, as well as similarly detailed > logging of the resulting assignment manager activity. However, an operator > may need to perform online and interactive observation, debugging, or > performance analysis of current balancer activity. Scraping and correlating > the many log lines resulting from a balancer execution is labor intensive and > has a lot of latency (order of ~minutes to acquire and index, order of > ~minutes to correlate). > The balancer should maintain a rolling window of history, e.g. the last 100 > region move plans, or last 1000 region move plans submitted to the assignment > manager. This history should include decision factor details and weights and > costs. The rsgroups balancer may be able to provide fairly simple decision > factors, like for example "this table was reassigned to that regionserver > group". The underlying or vanilla stochastic balancer on the other hand, > after a walk over random assignment plans, will have considered a number of > cost functions with various inputs (locality, load, etc.) and multipliers, > including custom cost functions. We can devise an extensible class structure > that represents explanations for balancer decisions, and for each region move > plan that is actually submitted to the assignment manager, we can keep the > explanations of all relevant decision factors alongside the other details of > the assignment plan like the region name, and the source and destination > regionservers. > This history should be available via API for use by new shell commands and > admin UI widgets. > The new shell commands and UI widgets can unpack the representation of > balancer decision components into human readable output. -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Updated] (HBASE-24528) Improve balancer decision observability
[ https://issues.apache.org/jira/browse/HBASE-24528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Viraj Jasani updated HBASE-24528: - Attachment: Screenshot 2020-08-15 at 8.08.57 PM.png > Improve balancer decision observability > --- > > Key: HBASE-24528 > URL: https://issues.apache.org/jira/browse/HBASE-24528 > Project: HBase > Issue Type: New Feature > Components: Admin, Balancer, Operability, shell, UI >Reporter: Andrew Kyle Purtell >Assignee: Viraj Jasani >Priority: Major > Attachments: Screenshot 2020-08-12 at 11.50.43 PM.png, Screenshot > 2020-08-15 at 8.08.57 PM.png > > > We provide detailed INFO and DEBUG level logging of balancer decision > factors, outcome, and reassignment planning, as well as similarly detailed > logging of the resulting assignment manager activity. However, an operator > may need to perform online and interactive observation, debugging, or > performance analysis of current balancer activity. Scraping and correlating > the many log lines resulting from a balancer execution is labor intensive and > has a lot of latency (order of ~minutes to acquire and index, order of > ~minutes to correlate). > The balancer should maintain a rolling window of history, e.g. the last 100 > region move plans, or last 1000 region move plans submitted to the assignment > manager. This history should include decision factor details and weights and > costs. The rsgroups balancer may be able to provide fairly simple decision > factors, like for example "this table was reassigned to that regionserver > group". The underlying or vanilla stochastic balancer on the other hand, > after a walk over random assignment plans, will have considered a number of > cost functions with various inputs (locality, load, etc.) and multipliers, > including custom cost functions. We can devise an extensible class structure > that represents explanations for balancer decisions, and for each region move > plan that is actually submitted to the assignment manager, we can keep the > explanations of all relevant decision factors alongside the other details of > the assignment plan like the region name, and the source and destination > regionservers. > This history should be available via API for use by new shell commands and > admin UI widgets. > The new shell commands and UI widgets can unpack the representation of > balancer decision components into human readable output. -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Updated] (HBASE-24528) Improve balancer decision observability
[ https://issues.apache.org/jira/browse/HBASE-24528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Viraj Jasani updated HBASE-24528: - Attachment: Screenshot 2020-08-12 at 11.50.43 PM.png > Improve balancer decision observability > --- > > Key: HBASE-24528 > URL: https://issues.apache.org/jira/browse/HBASE-24528 > Project: HBase > Issue Type: New Feature > Components: Admin, Balancer, Operability, shell, UI >Reporter: Andrew Kyle Purtell >Assignee: Viraj Jasani >Priority: Major > Attachments: Screenshot 2020-08-12 at 11.50.43 PM.png > > > We provide detailed INFO and DEBUG level logging of balancer decision > factors, outcome, and reassignment planning, as well as similarly detailed > logging of the resulting assignment manager activity. However, an operator > may need to perform online and interactive observation, debugging, or > performance analysis of current balancer activity. Scraping and correlating > the many log lines resulting from a balancer execution is labor intensive and > has a lot of latency (order of ~minutes to acquire and index, order of > ~minutes to correlate). > The balancer should maintain a rolling window of history, e.g. the last 100 > region move plans, or last 1000 region move plans submitted to the assignment > manager. This history should include decision factor details and weights and > costs. The rsgroups balancer may be able to provide fairly simple decision > factors, like for example "this table was reassigned to that regionserver > group". The underlying or vanilla stochastic balancer on the other hand, > after a walk over random assignment plans, will have considered a number of > cost functions with various inputs (locality, load, etc.) and multipliers, > including custom cost functions. We can devise an extensible class structure > that represents explanations for balancer decisions, and for each region move > plan that is actually submitted to the assignment manager, we can keep the > explanations of all relevant decision factors alongside the other details of > the assignment plan like the region name, and the source and destination > regionservers. > This history should be available via API for use by new shell commands and > admin UI widgets. > The new shell commands and UI widgets can unpack the representation of > balancer decision components into human readable output. -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Updated] (HBASE-24528) Improve balancer decision observability
[ https://issues.apache.org/jira/browse/HBASE-24528?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Sean Busbey updated HBASE-24528: Component/s: Operability > Improve balancer decision observability > --- > > Key: HBASE-24528 > URL: https://issues.apache.org/jira/browse/HBASE-24528 > Project: HBase > Issue Type: New Feature > Components: Admin, Balancer, Operability, shell, UI >Reporter: Andrew Kyle Purtell >Priority: Major > > We provide detailed INFO and DEBUG level logging of balancer decision > factors, outcome, and reassignment planning, as well as similarly detailed > logging of the resulting assignment manager activity. However, an operator > may need to perform online and interactive observation, debugging, or > performance analysis of current balancer activity. Scraping and correlating > the many log lines resulting from a balancer execution is labor intensive and > has a lot of latency (order of ~minutes to acquire and index, order of > ~minutes to correlate). > The balancer should maintain a rolling window of history, e.g. the last 100 > region move plans, or last 1000 region move plans submitted to the assignment > manager. This history should include decision factor details and weights and > costs. The rsgroups balancer may be able to provide fairly simple decision > factors, like for example "this table was reassigned to that regionserver > group". The underlying or vanilla stochastic balancer on the other hand, > after a walk over random assignment plans, will have considered a number of > cost functions with various inputs (locality, load, etc.) and multipliers, > including custom cost functions. We can devise an extensible class structure > that represents explanations for balancer decisions, and for each region move > plan that is actually submitted to the assignment manager, we can keep the > explanations of all relevant decision factors alongside the other details of > the assignment plan like the region name, and the source and destination > regionservers. > This history should be available via API for use by new shell commands and > admin UI widgets. > The new shell commands and UI widgets can unpack the representation of > balancer decision components into human readable output. -- This message was sent by Atlassian Jira (v8.3.4#803005)
