增加jvisualVM OQL结果集的最大大小

我有一个内存转储文件，它有近5000个特定对象的实例。 这些对象将被写入数据库，我这样做的方法是在jvisualvm中编写一个OQL查询，以生成一个字符串，用作SQL插入，例如

 select "insert into trades (id, tradeNumber) values ("+ x.id+ ", " + x.tradeNumber +");" from com.test.application.TradeObject x; 

当我通过OQL运行时，我得到一个这样的结果集 –

  insert into trades (id, tradeNumber) values (1,12345); insert into trades (id, tradeNumber) values (2,123456); insert into trades (id, tradeNumber) values (3,123457);  

等等

但是，由于实例总数很大（大约5000），JvisualVM只显示其中的大约100个。 然后出现错误消息“结果太多。请优化您的查询。”

我无法优化查询，因为我必须以这种方式解析所有实例。 有没有办法可以让JvisualVM向我显示所有实例而不限制结果数量？

我还看到Jvisual vm显示了没有任何filter的前100个实例，是否可以通过OQL查询获得接下来的100个实例等等？

谢谢

Answer 1

我在jvisualVm中找不到任何设置来增加结果集的大小。 可能是不可能的那种方式。 它看起来像Jvisualvm代码库中的硬编码限制。 参考： http ： //visualvm.sourcearchive.com/documentation/1.3/OQLController_8java-source.html

在那里找到以下片段：

 final AtomicInteger counter = new AtomicInteger(100); 

和

  if (counter.get() == 0) { sb.append("
Too many results. Please, refine your query.
" ); } else if (counter.get() == 100) { sb.append("
"); // NOI18N sb.append(NbBundle.getMessage(OQLController.class, "OQL_NO_RESULTS_MSG")); // NOI18N sb.append("
" ); // NOI18N } 

现在有趣的部分，你的问题的解决方法。

考虑下面的课程：

  package com.demo.test; class Xyz { int idXyz;// intentionally not set as id String value; public Xyz(int idXyz, String value) { this.idXyz = idXyz; this.value = value; } } 

现在说我在这个类的内存中有105个对象，保存在以下列表中：

  static List lst = new ArrayList<>(); for (int i = 0; i < 105; i++) { lst.add(new Xyz( i,"xyz value-" + i)); } 

我需要实现你正在做的事情。

现在要显示这105个对象而不是列出所有结果集，我宁愿遍历所有对象并创建一个包含由新行分隔的所有SQL查询的单个字符串。 为此，您需要在Query Editor调用类似的OQL脚本。

 function fun(objEnumeration){ var res =" "; while (objEnumeration.hasMoreElements()) { var itr = objEnumeration.nextElement(); var v = "insert into table_Xyz (idXyz, value) values ("+ itr.idXyz.toString()+ ", " + itr.value.toString() +");\n" res = res + v; } return res; } fun(heap.objects("com.demo.test.Xyz")); 

Query Results选项卡中的Query Results将是：

 insert into table_Xyz (idXyz, value) values (104, xyz value-104); insert into table_Xyz (idXyz, value) values (103, xyz value-103); insert into table_Xyz (idXyz, value) values (102, xyz value-102); insert into table_Xyz (idXyz, value) values (101, xyz value-101); insert into table_Xyz (idXyz, value) values (100, xyz value-100); insert into table_Xyz (idXyz, value) values (99, xyz value-99); insert into table_Xyz (idXyz, value) values (98, xyz value-98); insert into table_Xyz (idXyz, value) values (97, xyz value-97); insert into table_Xyz (idXyz, value) values (96, xyz value-96); insert into table_Xyz (idXyz, value) values (95, xyz value-95); insert into table_Xyz (idXyz, value) values (94, xyz value-94); insert into table_Xyz (idXyz, value) values (93, xyz value-93); insert into table_Xyz (idXyz, value) values (92, xyz value-92); insert into table_Xyz (idXyz, value) values (91, xyz value-91); insert into table_Xyz (idXyz, value) values (90, xyz value-90); insert into table_Xyz (idXyz, value) values (89, xyz value-89); insert into table_Xyz (idXyz, value) values (88, xyz value-88); insert into table_Xyz (idXyz, value) values (87, xyz value-87); insert into table_Xyz (idXyz, value) values (86, xyz value-86); insert into table_Xyz (idXyz, value) values (85, xyz value-85); insert into table_Xyz (idXyz, value) values (84, xyz value-84); insert into table_Xyz (idXyz, value) values (83, xyz value-83); insert into table_Xyz (idXyz, value) values (82, xyz value-82); insert into table_Xyz (idXyz, value) values (81, xyz value-81); insert into table_Xyz (idXyz, value) values (80, xyz value-80); insert into table_Xyz (idXyz, value) values (79, xyz value-79); insert into table_Xyz (idXyz, value) values (78, xyz value-78); insert into table_Xyz (idXyz, value) values (77, xyz value-77); insert into table_Xyz (idXyz, value) values (76, xyz value-76); insert into table_Xyz (idXyz, value) values (75, xyz value-75); insert into table_Xyz (idXyz, value) values (74, xyz value-74); insert into table_Xyz (idXyz, value) values (73, xyz value-73); insert into table_Xyz (idXyz, value) values (72, xyz value-72); insert into table_Xyz (idXyz, value) values (71, xyz value-71); insert into table_Xyz (idXyz, value) values (70, xyz value-70); insert into table_Xyz (idXyz, value) values (69, xyz value-69); insert into table_Xyz (idXyz, value) values (68, xyz value-68); insert into table_Xyz (idXyz, value) values (67, xyz value-67); insert into table_Xyz (idXyz, value) values (66, xyz value-66); insert into table_Xyz (idXyz, value) values (65, xyz value-65); insert into table_Xyz (idXyz, value) values (64, xyz value-64); insert into table_Xyz (idXyz, value) values (63, xyz value-63); insert into table_Xyz (idXyz, value) values (62, xyz value-62); insert into table_Xyz (idXyz, value) values (61, xyz value-61); insert into table_Xyz (idXyz, value) values (60, xyz value-60); insert into table_Xyz (idXyz, value) values (59, xyz value-59); insert into table_Xyz (idXyz, value) values (58, xyz value-58); insert into table_Xyz (idXyz, value) values (57, xyz value-57); insert into table_Xyz (idXyz, value) values (56, xyz value-56); insert into table_Xyz (idXyz, value) values (55, xyz value-55); insert into table_Xyz (idXyz, value) values (54, xyz value-54); insert into table_Xyz (idXyz, value) values (53, xyz value-53); insert into table_Xyz (idXyz, value) values (52, xyz value-52); insert into table_Xyz (idXyz, value) values (51, xyz value-51); insert into table_Xyz (idXyz, value) values (50, xyz value-50); insert into table_Xyz (idXyz, value) values (49, xyz value-49); insert into table_Xyz (idXyz, value) values (48, xyz value-48); insert into table_Xyz (idXyz, value) values (47, xyz value-47); insert into table_Xyz (idXyz, value) values (46, xyz value-46); insert into table_Xyz (idXyz, value) values (45, xyz value-45); insert into table_Xyz (idXyz, value) values (44, xyz value-44); insert into table_Xyz (idXyz, value) values (43, xyz value-43); insert into table_Xyz (idXyz, value) values (42, xyz value-42); insert into table_Xyz (idXyz, value) values (41, xyz value-41); insert into table_Xyz (idXyz, value) values (40, xyz value-40); insert into table_Xyz (idXyz, value) values (39, xyz value-39); insert into table_Xyz (idXyz, value) values (38, xyz value-38); insert into table_Xyz (idXyz, value) values (37, xyz value-37); insert into table_Xyz (idXyz, value) values (36, xyz value-36); insert into table_Xyz (idXyz, value) values (35, xyz value-35); insert into table_Xyz (idXyz, value) values (34, xyz value-34); insert into table_Xyz (idXyz, value) values (33, xyz value-33); insert into table_Xyz (idXyz, value) values (32, xyz value-32); insert into table_Xyz (idXyz, value) values (31, xyz value-31); insert into table_Xyz (idXyz, value) values (30, xyz value-30); insert into table_Xyz (idXyz, value) values (29, xyz value-29); insert into table_Xyz (idXyz, value) values (28, xyz value-28); insert into table_Xyz (idXyz, value) values (27, xyz value-27); insert into table_Xyz (idXyz, value) values (26, xyz value-26); insert into table_Xyz (idXyz, value) values (25, xyz value-25); insert into table_Xyz (idXyz, value) values (24, xyz value-24); insert into table_Xyz (idXyz, value) values (23, xyz value-23); insert into table_Xyz (idXyz, value) values (22, xyz value-22); insert into table_Xyz (idXyz, value) values (21, xyz value-21); insert into table_Xyz (idXyz, value) values (20, xyz value-20); insert into table_Xyz (idXyz, value) values (19, xyz value-19); insert into table_Xyz (idXyz, value) values (18, xyz value-18); insert into table_Xyz (idXyz, value) values (17, xyz value-17); insert into table_Xyz (idXyz, value) values (16, xyz value-16); insert into table_Xyz (idXyz, value) values (15, xyz value-15); insert into table_Xyz (idXyz, value) values (14, xyz value-14); insert into table_Xyz (idXyz, value) values (13, xyz value-13); insert into table_Xyz (idXyz, value) values (12, xyz value-12); insert into table_Xyz (idXyz, value) values (11, xyz value-11); insert into table_Xyz (idXyz, value) values (10, xyz value-10); insert into table_Xyz (idXyz, value) values (9, xyz value-9); insert into table_Xyz (idXyz, value) values (8, xyz value-8); insert into table_Xyz (idXyz, value) values (7, xyz value-7); insert into table_Xyz (idXyz, value) values (6, xyz value-6); insert into table_Xyz (idXyz, value) values (5, xyz value-5); insert into table_Xyz (idXyz, value) values (4, xyz value-4); insert into table_Xyz (idXyz, value) values (3, xyz value-3); insert into table_Xyz (idXyz, value) values (2, xyz value-2); insert into table_Xyz (idXyz, value) values (1, xyz value-1); insert into table_Xyz (idXyz, value) values (0, xyz value-0); 

只需修改OQL脚本以满足您的要求。

注意：在类Xyz中，字段idXyz intentionally not set as id ，因为在这种情况下itr.id将返回与该实例关联的对象id。

有关OQL方法的更多信息，请访问： http ： //visualvm.java.net/oqlhelp.html#toHtml

Answer 2

打开visualvm.conf文件：

 %JDK_HOME%\lib\visualvm\etc\visualvm.conf 

添加到以。开头的字符串

 visualvm_default_options=".... 

具有您所需限制值的财产

 -J-DOQLController.limitResults=999 

Answer 3

现在有可能（v 1.7），来自netbeans/profiler.heapwalker/src/org/netbeans/modules/profiler/heapwalk/OQLController.java ：

 private static final int RESULTS_LIMIT = \ Integer.parseInt(System.getProperty("OQLController.limitResults", "100")); // NOI18N 

我的帮助代码（如果你跳过limit – 然后无限制）：

 function loop1(iter, limit) { if (!iter.hasNext()) return "Nothing found!"; var count = 0; var html = ""; while (true) { if (count >= limit) return "First " + limit + " objects (not all):
" + html; if (!iter.hasNext()) return "Total " + count + " objects:
" + html; html += toHtml(iter.next()) + "
"; count += 1; } } function loop2(iter, limit) { if (!iter.hasMoreElements()) return "Nothing found!"; var count = 0; var html = ""; while (true) { if (count >= limit) return "First " + limit + " objects (not all):
" + html; if (!iter.hasMoreElements()) return "Total " + count + " objects:
" + html; html += toHtml(iter.nextElement()) + '
'; count += 1; } } function loop(iter, limit) { if ('hasMoreElements' in iter) return loop2(iter, limit); return loop1(iter, limit); } loop(filter(heap.classes(), "/javax.mail./(it.name)"), 1000) // loop1 loop(heap.objects('java.lang.ClassLoader')) // loop2 

更新我发现的另一个技巧是为变量赋值：

 x = filter(heap.objects("java.lang.String"), "/hibernate\\.ejb/(it.toString())") x 

结果对象具有查看器使用的接口next() / hasNext() 。 默认情况下，它显示100个条目。 但接下来只打电话：

 x 

显示接下来的100个条目等等……！