Depends on heap and size of tables (how many columns). Have seen many hundreds work fine. Could think of scenarios where dozens would fail (especially weird schemas or especially small heaps).
On Fri, May 4, 2018 at 11:39 AM, Abdul Patel <abd786...@gmail.com> wrote: > Thanks .. > So whats ideal number when we should stop ..say 100 ? > > > On Friday, May 4, 2018, Jeff Jirsa <jji...@gmail.com> wrote: > >> Cluster. The overhead is per cluster. >> >> There are two places you'll run into scaling pain here. >> >> 1) Size of the schema (which we have to serialize to send around) - too >> many tables, or too many columns in tables, can cause serializing schema to >> get really expensive and cause problems >> 2) Too many memtables - assume that all of them will have some tiny >> trivial amount of data in them, maybe 1MB. 200 * 1MB = 200MB of heap just >> for empty memtables. If you have a thousand tables, that's a gigabyte of >> heap, just for EMPTY memtables. >> >> >> >> >> >> On Fri, May 4, 2018 at 11:17 AM, Abdul Patel <abd786...@gmail.com> wrote: >> >>> I have 3 projects in pipeline adding 3 different cluster across all >>> environwments would too costly option :) >>> >>> So 200 tables per keyspace or per cluster? >>> >>> >>> On Friday, May 4, 2018, Durity, Sean R <sean_r_dur...@homedepot.com> >>> wrote: >>> >>>> The issue is more with the number of tables, not the number of >>>> keyspaces. Because each table has a memTable, there is a practical limit to >>>> the number of memtables that a node can hold in its memory. (And scaling >>>> out doesn’t help, because every node still has a memTable for every table.) >>>> The practical table limit I have heard is in the low hundreds – maybe 200 >>>> as a rough estimate. >>>> >>>> >>>> >>>> In general, we create a new cluster (instead of a new keyspace) for >>>> each application. >>>> >>>> >>>> >>>> >>>> >>>> Sean Durity >>>> >>>> *From:* Abdul Patel <abd786...@gmail.com> >>>> *Sent:* Thursday, May 03, 2018 5:56 PM >>>> *To:* User@cassandra.apache.org >>>> *Subject:* [EXTERNAL] Cassandra limitations >>>> >>>> >>>> >>>> Hi , >>>> >>>> >>>> >>>> In my environment, we are coming up with 3 to 4 new projects , hence >>>> new keyspaces will be coming into picture. >>>> >>>> Do we have any limitations or performance issues when we hit to a >>>> number of keyspaces or number of nodes vs keyspaces? >>>> >>>> Also connections limitations if any? >>>> >>>> >>>> >>>> I know as data grows we can add more nodes and memory but nor sure >>>> about somethinh else which need to take into consideration. >>>> >>>> >>>> >>>> >>>> >>>> ------------------------------ >>>> >>>> The information in this Internet Email is confidential and may be >>>> legally privileged. It is intended solely for the addressee. Access to this >>>> Email by anyone else is unauthorized. If you are not the intended >>>> recipient, any disclosure, copying, distribution or any action taken or >>>> omitted to be taken in reliance on it, is prohibited and may be unlawful. >>>> When addressed to our clients any opinions or advice contained in this >>>> Email are subject to the terms and conditions expressed in any applicable >>>> governing The Home Depot terms of business or client engagement letter. The >>>> Home Depot disclaims all responsibility and liability for the accuracy and >>>> content of this attachment and for any damages or losses arising from any >>>> inaccuracies, errors, viruses, e.g., worms, trojan horses, etc., or other >>>> items of a destructive nature, which may be contained in this attachment >>>> and shall not be liable for direct, indirect, consequential or special >>>> damages in connection with this e-mail message or its attachment. >>>> >>> >>
