Simple object pool with OpenTelemetry support

NuGet Packages

Package	Latest Version	About
ODA.ObjectPool		Object pool implementation

Documentation

Simple object pooling

You can use DefaultObjectPool class to create a pool of objects. DefaultObjectPool takes a bunch of settings and a factory

DefaultObjectPool<StringBuilder> pool = new(new Settings 
{ 
    MaxPoolSize = 100, 
    WaitingTimeout = 10000, 
    Name = "PoolName", 
    EvictionInterval = 2000 
},
() => new StringBuilder());

Setting	About
Name	Pool name. It is used for tagging telemetry metrics
MaxPoolSize	Pool size
WaitingTimeout	Number of milliseconds to wait for object renting from pool
EvictionInterval	Object pool periodically (once per EvictionInterval milliseconds) evicts items from pool.
EvictionTimeout	If pooled object is not used for at least EvictionTimeout milliseconds it is considered as unusable and will be evicted
ConcurrencyFactor	Setting for internal semaphore to control concurrency
BackoffDelayMilliseconds
BackoffMaxDelayMilliseconds

To rent an object from pool use Get method as follows:

using var pooledObject = await pool.Get().ConfigureAwait(false);

Get method returns a so called pooled object. When done, you must dispose pooled object to return rented object to the pool. You can use its Object property to gain acccess to underlying object:

pooledObject.Object.Append("Some string");

Database connection pooling

To create database connection pool, you must create an instance of DbConnectionPool. It is responsible for opening and closing database conections

DbConnectionPool pool = new(
  new Settings { 
    MaxPoolSize = 100, 
    WaitingTimeout = 10000, 
    Name = "PoolName",
    EvictionInterval = 2000 
  },
  () => { return new ClickHouseConnection(config["Clickhouse"]); });

To rent a connection from pool use Get method as follows:

using var connector = await pool.Get().ConfigureAwait(false);

To execute database commands you should use Object property to gain acccess to underlying database connection:

var command = connector.Object.CreateCommand();
command.CommandText = "SELECT 1";
byte? result = (byte?)command.ExecuteScalar();

When connection pool is no longer needed, please destroy it with Dispose method to clean up resources

OpenTelemetry metrics

Object pool uses metrics from System.Diagnostics which are usable for monitoring

Metric	About
pool_activeitems	Number of allocated items in pool
pool_evictions	Object pool periodically evicts not usable items from pool. This metric is in essence the number of times eviction was invoked
pool_activate_errors	Number of activation errors
pool_deactivate_errors	Number of deactivation errors
pool_cancellations	Number of cancellations

All metrics are tagged with the name of the pool