[ https://issues.apache.org/jira/browse/CASSANDRA-3750?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Sylvain Lebresne resolved CASSANDRA-3750. ----------------------------------------- Resolution: Duplicate While it is not yet committed, CASSANDRA-1391 will almost surely fix that, so marking that one as duplicate. > Migrations and Schema CFs use disk space proportional to the square of the > number of CFs > ---------------------------------------------------------------------------------------- > > Key: CASSANDRA-3750 > URL: https://issues.apache.org/jira/browse/CASSANDRA-3750 > Project: Cassandra > Issue Type: Bug > Components: Core > Affects Versions: 1.0.1 > Environment: Linux (CentOS 5.7) > Reporter: John Chakerian > Attachments: fit.png > > > The system keyspace grows proportional to the square of the number of CFs > (more likely, it grows quadratically with # of schema changes in general). > The major offenders in the keyspace are the Migrations table & the Schema > table. On clusters with very large #s of CFs (in the low thousands), we think > that these large system tables may be contributing to various performance > issues. > The approximate expression is: s = 0.0003253*n^2 + 2.58, where n is # of > keyspaces + # of schemas and s is the size of the system keyspace in > megabytes. See attached plot of the regression curve showing fit. > Sampled data: > {noformat} > NUM_CFS SYSTEM_SIZE_IN_MB > 100 4.4 > 200 15 > 300 32 > 400 55 > 500 85 > 600 120 > 700 162 > 800 211 > 900 266 > 1000 327 > {noformat} > This was hit in 1.0.1, but is almost certainly not version specific. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira