pool

I am a newbie to python,i am have function that calculate feature for my data and then return a list that should be processed and written in file.,..i am using Pool to do the calculation and then and use the callback function to write into file,however the callback function is not being call,i ve put some print statement in it but it is definetly not being called. my code looks like this: def write_arrow_format(results): print("writer called") results[1].to_csv("../data/model_data/feature-"+results[2],sep='\t',encoding='utf-8') with open('../data/model_data/arow-'+results[2],'w') as f: for dic

Tomcat 在 7.0 以前的版本都是使用 commons-dbcp 做为连接池的实现，但是 dbcp 饱受诟病，原因有： dbcp 是单线程的，为了保证线程安全会锁整个连接池 dbcp 性能不佳 dbcp 太复杂，超过 60 个类 dbcp 使用静态接口，在 JDK 1.6 编译有问题 dbcp 发展滞后 因此很多人会选择一些第三方的连接池组件，例如 c3p0 , bonecp, druid 等。 为此，Tomcat 从 7.0 开始引入一个新的模块：Tomcat jdbc pool tomcat jdbc pool 近乎兼容 dbcp ，性能更高 异步方式获取连接 tomcat jdbc pool 是 tomcat 的一个模块，基于 tomcat JULI，使用 Tomcat 的日志框架 使用 javax.sql.PooledConnection 接口获取连接 支持高并发应用环境 超简单，核心文件只有8个，比 c3p0 还 更好的空闲连接处理机制 支持 JMX 支持 XA Connection tomcat jdbc pool 的优点远不止这些，详情请看这里。 tomcat jdbc pool 可在 Tomcat 中直接使用，也可以在独立的应用中使用。 Tomcat 中直接使用的方法： 数据源配置： <Resource name="jdbc/TestDB" auth=

In couch base URL, e.g. server:port/pools/default what exactly a couch base pool is. Will it always be default or we can change it. There is some text written there http://www.couchbase.com/docs/couchbase-manual-1.8/couchbase-admin-restapi-key-concepts-resources.html but I cannot really get it 100%. Please anyone can explain. A long time ago the Couchbase engineers intended to build out a concept of having pools similar to zfs pools, but for a distributed database. The feature isn't dead, but just never got much attention compared to other database features that needed to be added. What ended

For SQL connection pool, why do we need to set up a min pool size? As connections will be saved in the connection pool and reused, why do we need to keep live connections specified by the min pool size? Thanks. Opening and maintaining connections is expensive, so if you know that you need multiple connections (always) it's better to specify the MinPoolSize because then it's ensured that these connections are available. Also, from MSDN : If MinPoolSize is either not specified in the connection string or is specified as zero, the connections in the pool will be closed after a period of

I am trying to load numpy files asynchronously in a Pool: self.pool = Pool(2, maxtasksperchild = 1) ... nextPackage = self.pool.apply_async(loadPackages, (...)) for fi in np.arange(len(files)): packages = nextPackage.get(timeout=30) # preload the next package asynchronously. It will be available # by the time it is required. nextPackage = self.pool.apply_async(loadPackages, (...)) The method "loadPackages": def loadPackages(... (2 strings & 2 ints) ...): print("This isn't printed!') packages = { "TRUE": np.load(gzip.GzipFile(path1, "r")), "FALSE": np.load(gzip.GzipFile(path2, "r")) } return

I need to execute a pool of many parallel database connections and queries. I would like to use a multiprocessing.Pool or concurrent.futures ProcessPoolExecutor. Python 2.7.5 In some cases, query requests take too long or will never finish (hung/zombie process). I would like to kill the specific process from the multiprocessing.Pool or concurrent.futures ProcessPoolExecutor that has timed out. Here is an example of how to kill/re-spawn the entire process pool, but ideally I would minimize that CPU thrashing since I only want to kill a specific long running process that has not returned data

I am looking for a good memory pool implementation in C. it should include the following: Anti fragmentation. Be super fast :) Ability to "bundle" several allocations from different sizes under some identifier and delete all the allocations with the given identifier. Thread safe I think the excellent talloc , developed as part of samba might be what you're looking for. The part I find most interesting is that any pointer returned from talloc is a valid memory context. Their example is: struct foo *X = talloc(mem_ctx, struct foo); X->name = talloc_strdup(X, "foo"); // ... talloc_free(X); //