Joe McDonnell has posted comments on this change. ( http://gerrit.cloudera.org:8080/19863 )
Change subject: IMPALA-11941: Support Java 17 in Impala ...................................................................... Patch Set 26: (1 comment) > I also added metrics and compared jamm vs ehcache for a few > operations after running > https://github.com/apache/impala/blob/master/tests/custom_cluster/test_local_catalog.py#L472-L518. > They're almost identical: > > Jamm: > catalog.cache.entry-99th-size 14.10 KB 99th percentile size of > Impalad Catalog cache entries. > catalog.cache.entry-median-size 376.00 B Median size of Impalad > Catalog cache entries. > catalog.cache.entry-stddev-size 2648.229397 Standard deviation for > size of Impalad Catalog cache entries. > > Ehcache: > catalog.cache.entry-99th-size 14.10 KB 99th percentile size of > Impalad Catalog cache entries. > catalog.cache.entry-median-size 376.00 B Median size of Impalad > Catalog cache entries. > catalog.cache.entry-stddev-size 2639.141904 Standard deviation for > size of Impalad Catalog cache entries. > > I can push up the additional changes to allow switching back to > ehcache and adding these metrics (not sure stddev is worth it when > 99th percentile is more readable). I agree that stddev might not be very useful. median and 99th percentile are useful. Is max useful? http://gerrit.cloudera.org:8080/#/c/19863/26/fe/src/main/java/org/apache/impala/catalog/local/CatalogdMetaProvider.java File fe/src/main/java/org/apache/impala/catalog/local/CatalogdMetaProvider.java: http://gerrit.cloudera.org:8080/#/c/19863/26/fe/src/main/java/org/apache/impala/catalog/local/CatalogdMetaProvider.java@2060 PS26, Line 2060: if (entrySize_ != null) { : entrySize_.update(size); : } So, the histogram and metrics are about everything that has been evaluated by the weigher. This is different from the current contents of the cache, because nothing happens on eviction. The metric is still useful, but maybe we need to be clear about it in the description. -- To view, visit http://gerrit.cloudera.org:8080/19863 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ic378896f572e030a3a019646a96a32a07866a737 Gerrit-Change-Number: 19863 Gerrit-PatchSet: 26 Gerrit-Owner: Michael Smith <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Joe McDonnell <[email protected]> Gerrit-Reviewer: Laszlo Gaal <[email protected]> Gerrit-Reviewer: Michael Smith <[email protected]> Gerrit-Reviewer: Quanlong Huang <[email protected]> Gerrit-Comment-Date: Wed, 21 Jun 2023 22:11:09 +0000 Gerrit-HasComments: Yes
