heap-memory

How to fix “Requested array size exceeds VM limit” error in Java?

由 此生再无相见时 提交于 2019-11-26 14:28:13
问题 Is there an log option that can let tomcat log the bad query instead just throwing this ? SEVERE: java.lang.OutOfMemoryError: Requested array size exceeds VM limit (Tried log level to FULL, but only capture the above) This is not enough information to further debug Alternatively, if this can be fixed by allocated more memory by tweaking the following? -Xms1024M -Xmx4096M -XX:MaxPermSize=256M Update -Xms6G -Xmx6G -XX:MaxPermSize=1G -XX:PermSize=512M (the above seems works better, keep

How is heap and stack memories managed, implemented, allocated?

由 烂漫一生 提交于 2019-11-26 14:16:11
问题 In C/C++ we can store variables, functions, member functions, instances of a class either on a stack or a heap. How is each implemented? How is it managed (high level)? Does gcc preallocates a chunk of memory to be used for the stack and heap, and then doles out on request? Is original memory coming from RAM? Can a function be allocated on the heap instead of a stack? Clarification I am really asking about implementation and management of heap and stack memories. After reading referenced

How to view the current heap size that an application is using?

由 主宰稳场 提交于 2019-11-26 12:54:43
问题 I think I increased my heap size to 1 GB in NetBeans since I changed the config to look like this: netbeans_default_options=\"-J-Xmx1g ...... After I restarted NetBeans, can I be sure that my app is given 1 GB now? Is there a way to verify this? 回答1: Use this code: // Get current size of heap in bytes long heapSize = Runtime.getRuntime().totalMemory(); // Get maximum size of heap in bytes. The heap cannot grow beyond this size.// Any attempt will result in an OutOfMemoryException. long

Why are two different concepts both called “heap”?

由 冷暖自知 提交于 2019-11-26 12:04:54
Why are the runtime heap used for dynamic memory allocation in C-style languages and the data structure both called "the heap"? Is there some relation? Donald Knuth says (The Art of Computer Programming, Third Ed., Vol. 1, p. 435): Several authors began about 1975 to call the pool of available memory a "heap." He doesn't say which authors and doesn't give references to any specific papers, but does say that the use of the term "heap" in relation to priority queues is the traditional sense of the word. They have the same name but they really aren't similar (even conceptually). A memory heap is

Node.js heap out of memory

由 泄露秘密 提交于 2019-11-26 12:03:49
Today I ran my script for filesystem indexing to refresh RAID files index and after 4h it crashed with following error: [md5:] 241613/241627 97.5% [md5:] 241614/241627 97.5% [md5:] 241625/241627 98.1% Creating missing list... (79570 files missing) Creating new files list... (241627 new files) <--- Last few GCs ---> 11629672 ms: Mark-sweep 1174.6 (1426.5) -> 1172.4 (1418.3) MB, 659.9 / 0 ms [allocation failure] [GC in old space requested]. 11630371 ms: Mark-sweep 1172.4 (1418.3) -> 1172.4 (1411.3) MB, 698.9 / 0 ms [allocation failure] [GC in old space requested]. 11631105 ms: Mark-sweep 1172.4

How to analyze memory using android studio

由 谁都会走 提交于 2019-11-26 08:42:42
问题 Recently switch to android studio from eclipse. How to check app heap and memory allocation in android studio? In Eclipse we have MAT is there anything in the studio to check heap dump, hprof file? 回答1: I'll explain it in an easy way with steps: First, you have install MAT ( download ) or use: brew cask install memoryanalyzer In Android Studio open Android Device Monitor or DDMS. Select your process "com.example.etc.." Click Update Heap above the process list. In the right-side panel, select

What is the largest possible heap size with a 64-bit JVM?

由 冷暖自知 提交于 2019-11-26 07:33:58
问题 The theoretical maximum heap value that can be set with -Xmx in a 32-bit system is of course 2^32 bytes, but typically (see: Understanding max JVM heap size - 32bit vs 64bit) one cannot use all 4GB. For a 64-bit JVM running in a 64-bit OS on a 64-bit machine, is there any limit besides the theoretical limit of 2^64 bytes or 16 exabytes? I know that for various reasons (mostly garbage collection), excessively large heaps might not be wise , but in light of reading about servers with terrabytes

Setting variable to NULL after free

由 丶灬走出姿态 提交于 2019-11-26 02:52:03
In my company there is a coding rule that says, after freeing any memory, reset the variable to NULL. For example ... void some_func () { int *nPtr; nPtr = malloc (100); free (nPtr); nPtr = NULL; return; } I feel that, in cases like the code shown above, setting to NULL does not have any meaning. Or am I missing something? If there is no meaning in such cases, I am going to take it up with the "quality team" to remove this coding rule. Please advice. Setting unused pointers to NULL is a defensive style, protecting against dangling pointer bugs. If a dangling pointer is accessed after it is

Node.js heap out of memory

由 ぐ巨炮叔叔 提交于 2019-11-26 01:56:44
问题 Today I ran my script for filesystem indexing to refresh RAID files index and after 4h it crashed with following error: [md5:] 241613/241627 97.5% [md5:] 241614/241627 97.5% [md5:] 241625/241627 98.1% Creating missing list... (79570 files missing) Creating new files list... (241627 new files) <--- Last few GCs ---> 11629672 ms: Mark-sweep 1174.6 (1426.5) -> 1172.4 (1418.3) MB, 659.9 / 0 ms [allocation failure] [GC in old space requested]. 11630371 ms: Mark-sweep 1172.4 (1418.3) -> 1172.4

Java heap terminology: young, old and permanent generations?

由 限于喜欢 提交于 2019-11-26 01:55:11
问题 I\'m trying to understand What the concepts of young , old and permanent generations are in the Java heap terminology, and more specifically the interactions between the three generations. My questions are: What is the young generation? What is the old generation? What is the permanent generation? How does the three generations interact/relate to each other? 回答1: This seems like a common misunderstanding. In Oracle's JVM, the permanent generation is not part of the heap. It's a separate space
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