Re: [EXTERNAL] Re: Garbage Collector

an Durity > > > > *From:* Jon Haddad > *Sent:* Tuesday, March 19, 2019 2:16 PM > *To:* user@cassandra.apache.org > *Subject:* [EXTERNAL] Re: Garbage Collector > > > > G1 is optimized for high throughput with higher pause times. It's great > if you have mixed

RE: [EXTERNAL] Re: Garbage Collector

: Garbage Collector G1 is optimized for high throughput with higher pause times. It's great if you have mixed / unpredictable workloads, and as Elliott mentioned is mostly set & forget. ZGC requires Java 11, which is only supported on trunk. I plan on messing with it soon, but I ha

Re: Garbage Collector

G1 is optimized for high throughput with higher pause times. It's great if you have mixed / unpredictable workloads, and as Elliott mentioned is mostly set & forget. ZGC requires Java 11, which is only supported on trunk. I plan on messing with it soon, but I haven't had time yet. We'll share t

Re: Garbage Collector

I use G1, and I think it's actually the default now for newer Cassandra versions. For G1, I've done very little custom config/tuning. I increased heap to 16GB (out of 64GB physical), but most of the rest is at or near default. For the most part, it's been "feed it more RAM, and it works" compare

Garbage Collector

Hi Folks, Does someone use G1 GC or ZGC on production? Can you share your feedback, the configuration used if it's possible ? Thanks.

RE: Cassandra and G1 Garbage collector stop the world event (STW)

Hi, my previously mentioned G1 bug does not seem to be related to your case Thomas From: Gustavo Scudeler [mailto:scudel...@gmail.com] Sent: Montag, 09. Oktober 2017 15:13 To: user@cassandra.apache.org Subject: Re: Cassandra and G1 Garbage collector stop the world event (STW) Hello, @kurt

Re: Cassandra and G1 Garbage collector stop the world event (STW)

n something >> called “humongous” allocations, spanning several G1 regions. If this >> happens in a very short very frequently and depending on your allocation >> rate in MB/s, a combination of the G1 bug and a small heap, might result >> going towards OOM. >> >>

Re: Cassandra and G1 Garbage collector stop the world event (STW)

tigation. > > > > Regards, > > Thomas > > > > *From:* Gustavo Scudeler [mailto:scudel...@gmail.com] > *Sent:* Montag, 09. Oktober 2017 13:12 > *To:* user@cassandra.apache.org > *Subject:* Cassandra and G1 Garbage collector stop the world event (STW) > >

RE: Cassandra and G1 Garbage collector stop the world event (STW)

scudel...@gmail.com] Sent: Montag, 09. Oktober 2017 13:12 To: user@cassandra.apache.org Subject: Cassandra and G1 Garbage collector stop the world event (STW) Hi guys, We have a 6 node Cassandra Cluster under heavy utilization. We have been dealing a lot with garbage collector stop the world event,

Re: Cassandra and G1 Garbage collector stop the world event (STW)

Have you tried CMS with that sized heap? G1 is only really worthwhile with 24gb+ heap size, which wouldn't really make sense on machines with 28gb of RAM. In general CMS is found to work better for C*, leaving excess memory to be utilised by the OS page cache​

Cassandra and G1 Garbage collector stop the world event (STW)

Hi guys, We have a 6 node Cassandra Cluster under heavy utilization. We have been dealing a lot with garbage collector stop the world event, which can take up to 50 seconds in our nodes, in the meantime Cassandra Node is unresponsive, not even accepting new logins. Extra details: - Cassandra

Re: Garbage collector launched on all nodes at once

How much memory do you have? Recently people have been seeing really great performance using G1GC with heaps > 8GB and offheap memtable objects. On Thu, Jun 18, 2015 at 1:31 AM Jason Wee wrote: > okay, iirc memtable has been removed off heap, google and got this > http://www.datastax.com/dev/bl

Re: Garbage collector launched on all nodes at once

okay, iirc memtable has been removed off heap, google and got this http://www.datastax.com/dev/blog/off-heap-memtables-in-Cassandra-2-1 apparently, there are still some reference on heap. On Thu, Jun 18, 2015 at 1:11 PM, Marcus Eriksson wrote: > It is probably this: https://issues.apache.org/ji

Re: Garbage collector launched on all nodes at once

It is probably this: https://issues.apache.org/jira/browse/CASSANDRA-9549 On Wed, Jun 17, 2015 at 7:37 PM, Michał Łowicki wrote: > Looks that memtable heap size is growing on some nodes rapidly ( > https://www.dropbox.com/s/3brloiy3fqang1r/Screenshot%202015-06-17%2019.21.49.png?dl=0). > Drops ar

Re: Garbage collector launched on all nodes at once

Looks that memtable heap size is growing on some nodes rapidly ( https://www.dropbox.com/s/3brloiy3fqang1r/Screenshot%202015-06-17%2019.21.49.png?dl=0). Drops are the places when nodes have been restarted. On Wed, Jun 17, 2015 at 6:53 PM, Michał Łowicki wrote: > Hi, > > Two datacenters with 6 no

Garbage collector launched on all nodes at once

Hi, Two datacenters with 6 nodes (2.1.6) each. In each DC garbage collection is launched at the same time on each node (See [1] for total GC duration per 5 seconds). RF is set to 3. Any ideas? [1] https://www.dropbox.com/s/bsbyew1jxbe3dgo/Screenshot%202015-06-17%2018.49.48.png?dl=0 -- BR, Micha

Re: JVM 7, Cass 1.1.1 and G1 garbage collector

> It is not a total waste, but practically your time is better spent in other > places. The problem is just about everything is a moving target, schema, > request rate, hardware. Generally tuning nudges a couple variables in one > direction or the other and you see some decent returns. But each nud

Re: JVM 7, Cass 1.1.1 and G1 garbage collector

er get back. Better to let SUN and other people worry about tuning (at least from where I sit) On Saturday, September 15, 2012, Peter Schuller wrote: >> Generally tuning the garbage collector is a waste of time. > > Sorry, that's BS. It can be absolutely critical, when done right,

Re: JVM 7, Cass 1.1.1 and G1 garbage collector

> Generally tuning the garbage collector is a waste of time. Sorry, that's BS. It can be absolutely critical, when done right, and only "useless" when done wrong. There's a spectrum in between. > Just follow > someone else's recommendation and use that. No

Re: JVM 7, Cass 1.1.1 and G1 garbage collector

Generally tuning the garbage collector is a waste of time. Just follow someone else's recommendation and use that. The problem with tuning is that workloads change then you have to tune again and again. New garbage collectors come out and you have to tune again and again. Someone at your co

Re: JVM 7, Cass 1.1.1 and G1 garbage collector

> Our full gc:s are typically not very frequent. Few days or even weeks > in between, depending on cluster. *PER NODE* that is. On a cluster of hundreds of nodes, that's pretty often (and all it takes is a single node). -- / Peter Schuller (@scode, http://worldmodscode.wordpress.com)

Re: JVM 7, Cass 1.1.1 and G1 garbage collector

> I was able to run IBM Java 7 with Cassandra (could not do it with 1.6 > because of snappy). It has a new Garbage collection policy (called balanced) > that is good for very large heap size (over 8 GB), documented here that is > so promising with Cassandra. I have not tried it but I like to see ho

Re: JVM 7, Cass 1.1.1 and G1 garbage collector

> Relatedly, I'd love to learn how to reliably reproduce full GC pauses > on C* 1.1+. Our full gc:s are typically not very frequent. Few days or even weeks in between, depending on cluster. But it happens on several clusters; I'm guessing most (but I haven't done a systematic analysis). The only q

Re: JVM 7, Cass 1.1.1 and G1 garbage collector

I was able to run IBM Java 7 with Cassandra (could not do it with 1.6 because of snappy). It has a new Garbage collection policy (called balanced) that is good for very large heap size (over 8 GB), documented

Re: JVM 7, Cass 1.1.1 and G1 garbage collector

Relatedly, I'd love to learn how to reliably reproduce full GC pauses on C* 1.1+. On Mon, Sep 10, 2012 at 12:37 PM, Oleg Dulin wrote: > I am currently profiling a Cassandra 1.1.1 set up using G1 and JVM 7. > > It is my feeble attempt to reduce Full GC pauses. > > Has anyone had any experience wit

Re: JVM 7, Cass 1.1.1 and G1 garbage collector

> I am currently profiling a Cassandra 1.1.1 set up using G1 and JVM 7. > > It is my feeble attempt to reduce Full GC pauses. > > Has anyone had any experience with this ? Anyone tried it ? Have tried; for some workloads it's looking promising. This is without key cache and row cache and with a pr

JVM 7, Cass 1.1.1 and G1 garbage collector

I am currently profiling a Cassandra 1.1.1 set up using G1 and JVM 7. It is my feeble attempt to reduce Full GC pauses. Has anyone had any experience with this ? Anyone tried it ? -- Regards, Oleg Dulin NYC Java Big Data Engineer http://www.olegdulin.com/