Add option for stacktrace filling

[mad]

Currently stacktrace filled by default but sometimes it is useless and affect on performance

[garydgregory]

@mad
Thank for your PR. You'll need to add unit tests.

@psteitz Any thoughts?

[psteitz]

I am not sure the added config complexity is worth it for this. Unless you are creating millions of pools, the performance impact of this is trivial. This code is run only once, when the pool is created. I am afraid that users would end up confused into thinking this was about pooled objects - basically needless cognitive load for 99.99% of users.

[garydgregory]

Closing, see above.

[mad]

@garydgregory

I'll try to explain why this is required.

Some database have transactions; in transactions, entities are created that can be reused in case of multithreading (cursors). To minimize the number of cursors (and their creation), a pool of objects is used

In the case of a large number of transactions, the cost of initializing the stack trace becomes noticeable. The external pool is not convenient to hold, because its lifetime is equal to the transaction lifetime

Benchmark result (https://gist.github.com/mad/91e7b587cd7677ef04139d805219e318)

Benchmark               (withStackTrace)   Mode  Cnt       Score   Error  Units
PoolBench.bench                     true  thrpt        87312.389          ops/s
PoolBench.bench:·stack              true  thrpt              NaN            ---
PoolBench.bench                    false  thrpt       350373.113          ops/s
PoolBench.bench:·stack             false  thrpt              NaN            ---

Profiling

w/ stacktrace
....[Thread state: RUNNABLE]........................................................................
 25.0%  33.3% <stack is empty, everything is filtered?>
 25.0%  33.3% com.intellij.rt.execution.application.AppMainV2$1.run
 15.6%  20.9% org.apache.commons.pool3.impl.BaseGenericObjectPool.getStackTrace
  5.1%   6.8% org.apache.commons.pool3.impl.BaseGenericObjectPool$StatsStore.<init>
  2.8%   3.7% org.apache.commons.pool3.impl.BaseGenericObjectPool.<init>
  1.2%   1.6% org.apache.commons.pool3.impl.BaseGenericObjectPool.setEvictionPolicy
  0.1%   0.1% org.apache.commons.pool3.impl.LinkedBlockingDeque.interuptTakeWaiters
  0.0%   0.1% org.apache.commons.pool3.impl.BaseGenericObjectPool.setEvictionPolicyClassName
  0.0%   0.1% org.apache.commons.pool3.impl.BaseGenericObjectPool$StatsStore.lambda$new$0
  0.0%   0.0% com.bic.jmh.PoolBench.bench
  0.1%   0.1% <other>


w/o stacktrace
....[Thread state: RUNNABLE]........................................................................
 25.0%  33.3% <stack is empty, everything is filtered?>
 25.0%  33.3% com.intellij.rt.execution.application.AppMainV2$1.run
 19.9%  26.5% org.apache.commons.pool3.impl.BaseGenericObjectPool$StatsStore.<init>
  4.0%   5.4% org.apache.commons.pool3.impl.BaseGenericObjectPool.setEvictionPolicy
  0.6%   0.9% com.bic.jmh.PoolBench.bench
  0.2%   0.3% org.apache.commons.pool3.impl.BaseGenericObjectPool.setEvictionPolicyClassName
  0.2%   0.2% org.apache.commons.pool3.impl.BaseGenericObjectPool$StatsStore.lambda$new$0
  0.0%   0.0% com.bic.jmh.generated.PoolBench_bench_jmhTest.bench_thrpt_jmhStub
  0.0%   0.0% org.apache.commons.pool3.impl.GenericObjectPoolConfig.<init>
  0.0%   0.0% org.apache.commons.pool3.impl.GenericObjectPool.<init>