Use intern() to reuse strings and reduce memory usage / save 6% ---------------------------------------------------------------- Key: HHH-5232 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-5232 Project: Hibernate Core Issue Type: Patch Components: core Affects Versions: 3.6 Environment: Hibernate 3.6.0-SNAPSHOT Linux x86_64 Bits Reporter: Yves Galante Assignee: Gail Badner Priority: Minor Attachments: DuplicateString.patch Original Estimate: 2h Remaining Estimate: 2h This patch is an update of JIRRA HHH-3924 for Hibernate 3.6. Testsuite executed without new failures. Resume of the original JIRRA HHH-3924 : >>DefaultEntityAliases suffix and rowIdAliases String fields are not interned as are other fields in the class. This leads to significant >>of memory usage on our application. >>BasicLoader suffixes and QueryLoader sqlAliasSuffixes can also be interned so as to save more memory See the detailed result of this patch : ======================================== Test conditions ======================================== Hibernate version : 3.6.0-SNAPSHOT Yourkit : 8.0 OS : Linux x86_64 Bits. Test case : org.hibernate.test.legacy.ParentChildTest.testReplicate() Time : Memory snapshot is taken at the of the test. ======================================== Result before patch ======================================== SessionFactoryImpl size : 3939 KB Duplicates String example : "0_" : 452 duplicates (32KB) "rowid_0_" : 405 duplicates (32KB) "1_" : 145 duplicates (10KB) "rowid_1_" : 130 duplicates (10KB) ... "fee3_" : 65 duplicates (5KB) "glarch1_" : 55 duplicates (5KB) ... "foo2_2_5" : 46 duplicates (3KB) ... "string" : 28 duplicates (2KB) ======================================== Result after patch ======================================== SessionFactoryImpl size : 3688 KB Save 251 Kb, 6% of the session factory size.