From: Lionel F. <lio...@gm...> - 2011-05-31 07:26:11
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Hi, yes, persistent_datanode_connections is now set to off - it may not be related to the issues I have. What amount of memory do you have on your datanodes & coordinator ? Here are my settings : datanode : shared_buffers = 512MB coordinator=256MB (now, was 96MB) I still get for some distributed tables (by hash) "ERROR: Could not commit prepared transaction implicitely" For distribution syntax, yes, I found your webpage talking about regression tests > You also have to know that it is important to set a limit of connections on > datanodes equal to the sum of max connections on all coordinators. > For example, if your cluster is using 2 coordinator with 20 max connections > each, you may have a maximum of 40 connections to datanodes. Ok, tweaking this today and launching the tests again... Lionel F. 2011/5/31 Michael Paquier <mic...@gm...>: > > > On Mon, May 30, 2011 at 7:34 PM, Lionel Frachon <lio...@gm...> > wrote: >> >> Hi again, >> >> I turned off connection pooling on coordinator (dunno why it sayed >> on), raised the shared_buffers of coordinator, allowed 1000 >> connections and the error disappeared. > > I am not really sure I get the meaning of this, but how did you turn off > pooler on coordinator. > Did you use the parameter persistent_connections? > Connection pooling from coordinator is an automatic feature and you have to > use it if you want to connect from a remote coordinator to backend XC nodes. > > You also have to know that it is important to set a limit of connections on > datanodes equal to the sum of max connections on all coordinators. > For example, if your cluster is using 2 coordinator with 20 max connections > each, you may have a maximum of 40 connections to datanodes. > This uses a lot of shared buffer on a node, but typically this maximum > number of connections is never reached thanks to the connection pooling. > > Please node also that number of Coordinator <-> Coordinator connections may > also increase if DDL are used from several coordinators. > >> However, all data is still going on one node (and whatever I could >> choose as primary datanode), with 40 warehouses... any specific syntax >> to load balance warehouses over nodes ? > > CREATE TABLE foo (column_key type, other_column int) DISTRIBUTE BY > HASH(column_key); > -- > Michael Paquier > http://michael.otacoo.com > |