[jira] [Updated] (CASSANDRA-13241) Lower default chunk_length_in_kb from 64kb to 16kb
[ https://issues.apache.org/jira/browse/CASSANDRA-13241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ariel Weisberg updated CASSANDRA-13241: --- Resolution: Fixed Fix Version/s: 4.0 Status: Resolved (was: Ready to Commit) Committed as [caf50de31b034ed77140b3c1597e7ca6ddc44e17|https://github.com/apache/cassandra/commit/caf50de31b034ed77140b3c1597e7ca6ddc44e17] thanks! test_disk_balance_after_boundary_change_lcs - disk_balance_test.TestDiskBalance failed, but I couldn't reproduce it after running it a few times. I have seen it being flaky before. > Lower default chunk_length_in_kb from 64kb to 16kb > -- > > Key: CASSANDRA-13241 > URL: https://issues.apache.org/jira/browse/CASSANDRA-13241 > Project: Cassandra > Issue Type: Wish > Components: Core >Reporter: Benjamin Roth >Assignee: Ariel Weisberg >Priority: Major > Fix For: 4.0 > > Attachments: CompactIntegerSequence.java, > CompactIntegerSequenceBench.java, CompactSummingIntegerSequence.java > > > Having a too low chunk size may result in some wasted disk space. A too high > chunk size may lead to massive overreads and may have a critical impact on > overall system performance. > In my case, the default chunk size lead to peak read IOs of up to 1GB/s and > avg reads of 200MB/s. After lowering chunksize (of course aligned with read > ahead), the avg read IO went below 20 MB/s, rather 10-15MB/s. > The risk of (physical) overreads is increasing with lower (page cache size) / > (total data size) ratio. > High chunk sizes are mostly appropriate for bigger payloads pre request but > if the model consists rather of small rows or small resultsets, the read > overhead with 64kb chunk size is insanely high. This applies for example for > (small) skinny rows. > Please also see here: > https://groups.google.com/forum/#!topic/scylladb-dev/j_qXSP-6-gY > To give you some insights what a difference it can make (460GB data, 128GB > RAM): > - Latency of a quite large CF: https://cl.ly/1r3e0W0S393L > - Disk throughput: https://cl.ly/2a0Z250S1M3c > - This shows, that the request distribution remained the same, so no "dynamic > snitch magic": https://cl.ly/3E0t1T1z2c0J -- This message was sent by Atlassian JIRA (v7.6.3#76005) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Updated] (CASSANDRA-13241) Lower default chunk_length_in_kb from 64kb to 16kb
[ https://issues.apache.org/jira/browse/CASSANDRA-13241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ariel Weisberg updated CASSANDRA-13241: --- Status: Ready to Commit (was: Patch Available) > Lower default chunk_length_in_kb from 64kb to 16kb > -- > > Key: CASSANDRA-13241 > URL: https://issues.apache.org/jira/browse/CASSANDRA-13241 > Project: Cassandra > Issue Type: Wish > Components: Core >Reporter: Benjamin Roth >Assignee: Ariel Weisberg >Priority: Major > Attachments: CompactIntegerSequence.java, > CompactIntegerSequenceBench.java, CompactSummingIntegerSequence.java > > > Having a too low chunk size may result in some wasted disk space. A too high > chunk size may lead to massive overreads and may have a critical impact on > overall system performance. > In my case, the default chunk size lead to peak read IOs of up to 1GB/s and > avg reads of 200MB/s. After lowering chunksize (of course aligned with read > ahead), the avg read IO went below 20 MB/s, rather 10-15MB/s. > The risk of (physical) overreads is increasing with lower (page cache size) / > (total data size) ratio. > High chunk sizes are mostly appropriate for bigger payloads pre request but > if the model consists rather of small rows or small resultsets, the read > overhead with 64kb chunk size is insanely high. This applies for example for > (small) skinny rows. > Please also see here: > https://groups.google.com/forum/#!topic/scylladb-dev/j_qXSP-6-gY > To give you some insights what a difference it can make (460GB data, 128GB > RAM): > - Latency of a quite large CF: https://cl.ly/1r3e0W0S393L > - Disk throughput: https://cl.ly/2a0Z250S1M3c > - This shows, that the request distribution remained the same, so no "dynamic > snitch magic": https://cl.ly/3E0t1T1z2c0J -- This message was sent by Atlassian JIRA (v7.6.3#76005) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Updated] (CASSANDRA-13241) Lower default chunk_length_in_kb from 64kb to 16kb
[ https://issues.apache.org/jira/browse/CASSANDRA-13241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Jon Haddad updated CASSANDRA-13241: --- Reviewer: Jon Haddad > Lower default chunk_length_in_kb from 64kb to 16kb > -- > > Key: CASSANDRA-13241 > URL: https://issues.apache.org/jira/browse/CASSANDRA-13241 > Project: Cassandra > Issue Type: Wish > Components: Core >Reporter: Benjamin Roth >Assignee: Ariel Weisberg >Priority: Major > Attachments: CompactIntegerSequence.java, > CompactIntegerSequenceBench.java, CompactSummingIntegerSequence.java > > > Having a too low chunk size may result in some wasted disk space. A too high > chunk size may lead to massive overreads and may have a critical impact on > overall system performance. > In my case, the default chunk size lead to peak read IOs of up to 1GB/s and > avg reads of 200MB/s. After lowering chunksize (of course aligned with read > ahead), the avg read IO went below 20 MB/s, rather 10-15MB/s. > The risk of (physical) overreads is increasing with lower (page cache size) / > (total data size) ratio. > High chunk sizes are mostly appropriate for bigger payloads pre request but > if the model consists rather of small rows or small resultsets, the read > overhead with 64kb chunk size is insanely high. This applies for example for > (small) skinny rows. > Please also see here: > https://groups.google.com/forum/#!topic/scylladb-dev/j_qXSP-6-gY > To give you some insights what a difference it can make (460GB data, 128GB > RAM): > - Latency of a quite large CF: https://cl.ly/1r3e0W0S393L > - Disk throughput: https://cl.ly/2a0Z250S1M3c > - This shows, that the request distribution remained the same, so no "dynamic > snitch magic": https://cl.ly/3E0t1T1z2c0J -- This message was sent by Atlassian JIRA (v7.6.3#76005) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Updated] (CASSANDRA-13241) Lower default chunk_length_in_kb from 64kb to 16kb
[ https://issues.apache.org/jira/browse/CASSANDRA-13241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ariel Weisberg updated CASSANDRA-13241: --- Status: Patch Available (was: Open) > Lower default chunk_length_in_kb from 64kb to 16kb > -- > > Key: CASSANDRA-13241 > URL: https://issues.apache.org/jira/browse/CASSANDRA-13241 > Project: Cassandra > Issue Type: Wish > Components: Core >Reporter: Benjamin Roth >Assignee: Ariel Weisberg >Priority: Major > Attachments: CompactIntegerSequence.java, > CompactIntegerSequenceBench.java, CompactSummingIntegerSequence.java > > > Having a too low chunk size may result in some wasted disk space. A too high > chunk size may lead to massive overreads and may have a critical impact on > overall system performance. > In my case, the default chunk size lead to peak read IOs of up to 1GB/s and > avg reads of 200MB/s. After lowering chunksize (of course aligned with read > ahead), the avg read IO went below 20 MB/s, rather 10-15MB/s. > The risk of (physical) overreads is increasing with lower (page cache size) / > (total data size) ratio. > High chunk sizes are mostly appropriate for bigger payloads pre request but > if the model consists rather of small rows or small resultsets, the read > overhead with 64kb chunk size is insanely high. This applies for example for > (small) skinny rows. > Please also see here: > https://groups.google.com/forum/#!topic/scylladb-dev/j_qXSP-6-gY > To give you some insights what a difference it can make (460GB data, 128GB > RAM): > - Latency of a quite large CF: https://cl.ly/1r3e0W0S393L > - Disk throughput: https://cl.ly/2a0Z250S1M3c > - This shows, that the request distribution remained the same, so no "dynamic > snitch magic": https://cl.ly/3E0t1T1z2c0J -- This message was sent by Atlassian JIRA (v7.6.3#76005) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Updated] (CASSANDRA-13241) Lower default chunk_length_in_kb from 64kb to 16kb
[ https://issues.apache.org/jira/browse/CASSANDRA-13241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ariel Weisberg updated CASSANDRA-13241: --- Status: Open (was: Patch Available) > Lower default chunk_length_in_kb from 64kb to 16kb > -- > > Key: CASSANDRA-13241 > URL: https://issues.apache.org/jira/browse/CASSANDRA-13241 > Project: Cassandra > Issue Type: Wish > Components: Core >Reporter: Benjamin Roth >Assignee: Ariel Weisberg >Priority: Major > Attachments: CompactIntegerSequence.java, > CompactIntegerSequenceBench.java, CompactSummingIntegerSequence.java > > > Having a too low chunk size may result in some wasted disk space. A too high > chunk size may lead to massive overreads and may have a critical impact on > overall system performance. > In my case, the default chunk size lead to peak read IOs of up to 1GB/s and > avg reads of 200MB/s. After lowering chunksize (of course aligned with read > ahead), the avg read IO went below 20 MB/s, rather 10-15MB/s. > The risk of (physical) overreads is increasing with lower (page cache size) / > (total data size) ratio. > High chunk sizes are mostly appropriate for bigger payloads pre request but > if the model consists rather of small rows or small resultsets, the read > overhead with 64kb chunk size is insanely high. This applies for example for > (small) skinny rows. > Please also see here: > https://groups.google.com/forum/#!topic/scylladb-dev/j_qXSP-6-gY > To give you some insights what a difference it can make (460GB data, 128GB > RAM): > - Latency of a quite large CF: https://cl.ly/1r3e0W0S393L > - Disk throughput: https://cl.ly/2a0Z250S1M3c > - This shows, that the request distribution remained the same, so no "dynamic > snitch magic": https://cl.ly/3E0t1T1z2c0J -- This message was sent by Atlassian JIRA (v7.6.3#76005) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Updated] (CASSANDRA-13241) Lower default chunk_length_in_kb from 64kb to 16kb
[ https://issues.apache.org/jira/browse/CASSANDRA-13241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ariel Weisberg updated CASSANDRA-13241: --- Status: Patch Available (was: Open) [trunk patch|https://github.com/apache/cassandra/compare/trunk...aweisberg:13241-trunk?expand=1] [CircleCI|https://circleci.com/gh/aweisberg/cassandra/tree/13241-trunk] CircleCI link doesn't work yet. They are backed up due to the github outage. > Lower default chunk_length_in_kb from 64kb to 16kb > -- > > Key: CASSANDRA-13241 > URL: https://issues.apache.org/jira/browse/CASSANDRA-13241 > Project: Cassandra > Issue Type: Wish > Components: Core >Reporter: Benjamin Roth >Assignee: Ariel Weisberg >Priority: Major > Attachments: CompactIntegerSequence.java, > CompactIntegerSequenceBench.java, CompactSummingIntegerSequence.java > > > Having a too low chunk size may result in some wasted disk space. A too high > chunk size may lead to massive overreads and may have a critical impact on > overall system performance. > In my case, the default chunk size lead to peak read IOs of up to 1GB/s and > avg reads of 200MB/s. After lowering chunksize (of course aligned with read > ahead), the avg read IO went below 20 MB/s, rather 10-15MB/s. > The risk of (physical) overreads is increasing with lower (page cache size) / > (total data size) ratio. > High chunk sizes are mostly appropriate for bigger payloads pre request but > if the model consists rather of small rows or small resultsets, the read > overhead with 64kb chunk size is insanely high. This applies for example for > (small) skinny rows. > Please also see here: > https://groups.google.com/forum/#!topic/scylladb-dev/j_qXSP-6-gY > To give you some insights what a difference it can make (460GB data, 128GB > RAM): > - Latency of a quite large CF: https://cl.ly/1r3e0W0S393L > - Disk throughput: https://cl.ly/2a0Z250S1M3c > - This shows, that the request distribution remained the same, so no "dynamic > snitch magic": https://cl.ly/3E0t1T1z2c0J -- This message was sent by Atlassian JIRA (v7.6.3#76005) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
[jira] [Updated] (CASSANDRA-13241) Lower default chunk_length_in_kb from 64kb to 16kb
[ https://issues.apache.org/jira/browse/CASSANDRA-13241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Ariel Weisberg updated CASSANDRA-13241: --- Summary: Lower default chunk_length_in_kb from 64kb to 16kb (was: Lower default chunk_length_in_kb from 64kb to 4kb) > Lower default chunk_length_in_kb from 64kb to 16kb > -- > > Key: CASSANDRA-13241 > URL: https://issues.apache.org/jira/browse/CASSANDRA-13241 > Project: Cassandra > Issue Type: Wish > Components: Core >Reporter: Benjamin Roth >Assignee: Ariel Weisberg >Priority: Major > Attachments: CompactIntegerSequence.java, > CompactIntegerSequenceBench.java, CompactSummingIntegerSequence.java > > > Having a too low chunk size may result in some wasted disk space. A too high > chunk size may lead to massive overreads and may have a critical impact on > overall system performance. > In my case, the default chunk size lead to peak read IOs of up to 1GB/s and > avg reads of 200MB/s. After lowering chunksize (of course aligned with read > ahead), the avg read IO went below 20 MB/s, rather 10-15MB/s. > The risk of (physical) overreads is increasing with lower (page cache size) / > (total data size) ratio. > High chunk sizes are mostly appropriate for bigger payloads pre request but > if the model consists rather of small rows or small resultsets, the read > overhead with 64kb chunk size is insanely high. This applies for example for > (small) skinny rows. > Please also see here: > https://groups.google.com/forum/#!topic/scylladb-dev/j_qXSP-6-gY > To give you some insights what a difference it can make (460GB data, 128GB > RAM): > - Latency of a quite large CF: https://cl.ly/1r3e0W0S393L > - Disk throughput: https://cl.ly/2a0Z250S1M3c > - This shows, that the request distribution remained the same, so no "dynamic > snitch magic": https://cl.ly/3E0t1T1z2c0J -- This message was sent by Atlassian JIRA (v7.6.3#76005) - To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
