memory

android memory usage and heap usage

由 流过昼夜 提交于 2020-01-17 03:49:07
问题 when I look at my application in a memory utility (like Memory Usage app), it shows my application using 33MB of memory. If while debugging my app, I go into DDMS and look at the heap, it's taking 4MB. So at this point, I'm wondering where the other 29MB is being chewed up by. Secondly, my concern is that I could wind up spending a huge amount of time trying to trim that 4MB to something much smaller like say 2-3MB, but that hardly seems like I'm putting a dent in the memory usage. So how do

python学习之关系型数据库作业

由 蹲街弑〆低调 提交于 2020-01-16 18:36:17
简答题 1.MySQL常见的三种存储引擎（InnoDB、MyISAM、MEMORY）的区别(至少5点)？ l InnoDB存储引擎 InnoDB是事务型数据库的首选引擎，支持事务安全表（ACID），其它存储引擎都是非事务安全表，支持行锁定和外键，MySQL5.5以后默认使用InnoDB存储引擎。 InnoDB主要特性 为MySQL提供了具有提交、回滚和崩溃恢复能力的事务安全（ACID兼容）存储引擎。InnoDB锁定在行级并且也在 SELECT语句中提供一个类似Oracle的非锁定读。这些功能增加了多用户部署和性能。在SQL查询中，可以自由地将InnoDB类型的表和其他MySQL的表类型混合起来，甚至在同一个查询中也可以混合。 。 l MyISAM存储引擎 MyISAM基于ISAM存储引擎，并对其进行扩展。它是在Web、数据仓储和其他应用环境下最常使用的存储引擎之一。MyISAM拥有较高的插入、查询速度，但不支持事务，不支持外键。 MyISAM主要特性： 被大文件系统和操作系统支持。 当把删除和更新及插入操作混合使用的时候，动态尺寸的行产生更少碎片。这要通过合并相邻被删除的块，若下一个块被删除，就扩展到下一块自动完成。 每个MyISAM表最大索引数是64，这可以通过重新编译来改变。每个索引最大的列数是16。 最大的键长度是1000字节，这也可以通过编译来改变

Concatenating a string and byte array in to unmanaged memory

由 老子叫甜甜 提交于 2020-01-16 18:30:27
问题 This is a followup to my last question. I now have a byte[] of values for my bitmap image. Eventually I will be passing a string to the print spooler of the format String.Format("GW{0},{1},{2},{3},", X, Y, stride, _Bitmap.Height) + my binary data; I am using the SendBytesToPrinter command from here. Here is my code so far to send it to the printer public static bool SendStringPlusByteBlockToPrinter(string szPrinterName, string szString, byte[] bytes) { IntPtr pBytes; Int32 dwCount; // How

Concatenating a string and byte array in to unmanaged memory

由 ＊爱你＆永不变心＊ 提交于 2020-01-16 18:30:07
问题 This is a followup to my last question. I now have a byte[] of values for my bitmap image. Eventually I will be passing a string to the print spooler of the format String.Format("GW{0},{1},{2},{3},", X, Y, stride, _Bitmap.Height) + my binary data; I am using the SendBytesToPrinter command from here. Here is my code so far to send it to the printer public static bool SendStringPlusByteBlockToPrinter(string szPrinterName, string szString, byte[] bytes) { IntPtr pBytes; Int32 dwCount; // How

Bits in a memory address

由 六月ゝ 毕业季﹏ 提交于 2020-01-16 18:26:09
问题 While debugging on Windows XP 32-bit using the immunity debugger, I see the following on the stack: _Address_ -Value_ 00ff2254 ff090045 00ff2258 00000002 My understanding is that every address location contains 8 bits. Is this correct? 回答1: If I'm understanding your question correctly, the answer is yes, every individual memory location contains 8 bits. The debugger is showing you 4 bytes (32 bits) at a time, to make the display more compact (and because many data types take up 32 bits, so it

PHP - Fatal Error - is any way to not stop script? [duplicate]

由 巧了我就是萌 提交于 2020-01-16 10:12:30
问题 This question already has answers here : Safely catch a 'Allowed memory size exhausted' error in PHP (4 answers) Closed 2 years ago . I have a simple script: <?php $source = '../path/img.jpg'; $image = imagecreatefromjpeg($source); ?> Finally I got: Fatal Error: Allowed Memory Size of 134217728 Bytes Exhausted But when I try do something like that: <?php $source = '../path/img.jpg'; $image = @imagecreatefromjpeg($source); // Mute Fatal Error if ( !$image ) { die('Image file is too large'); }

tracemalloc - Trace memory allocations - 跟踪内存分配

由 风流意气都作罢 提交于 2020-01-16 08:10:12
tracemalloc - Trace memory allocations - 跟踪内存分配 tracemalloc - 跟踪内存分配 https://docs.python.org/zh-cn/3.8/library/tracemalloc.html tracemalloc - Trace memory allocations https://docs.python.org/3.8/library/tracemalloc.html Source code: Lib/tracemalloc.py The tracemalloc module is a debug tool to trace memory blocks allocated by Python. It provides the following information: tracemalloc 模块是一个调试工具，用于跟踪 Python 分配的内存块。它提供以下信息： Traceback where an object was allocated - 分配对象的回溯 Statistics on allocated memory blocks per filename and per line number: total size, number and average size of allocated

Python Memory Issue with BeautifulSoup

由 你离开我真会死。 提交于 2020-01-16 06:06:18
问题 I've resolved this issue, but I'm wondering why it was caused in the first place. I used BeautifulSoup to identify this span from a webpage: span = <span id="ctl00_ContentPlaceHolder1_RestInfoReskin_lblRestName">Ally's Sizzlers</span> I then assign this variable: restaurant.name = span.contents However on each loop this takes up a full 1 MB, and there's about 20,000 loops. Through trial and error I came upon this solution: restaurant.name = str(span.contents) Can you tell me why the former

Python Memory Issue with BeautifulSoup

由 馋奶兔 提交于 2020-01-16 06:05:29
问题 I've resolved this issue, but I'm wondering why it was caused in the first place. I used BeautifulSoup to identify this span from a webpage: span = <span id="ctl00_ContentPlaceHolder1_RestInfoReskin_lblRestName">Ally's Sizzlers</span> I then assign this variable: restaurant.name = span.contents However on each loop this takes up a full 1 MB, and there's about 20,000 loops. Through trial and error I came upon this solution: restaurant.name = str(span.contents) Can you tell me why the former

Fast way to copy part of an array into a List?

由 痞子三分冷 提交于 2020-01-16 05:31:08
问题 C#'s List<> has a set of CopyTo functions that will extract the contents of its internal array into another array using a fast memory block copy. Is there a way to do this in reverse? It might look like... var buffer = new List<byte>(); buffer.AddRange(afewbytes); buffer.AddFromArray(myArray, startIndex, countBytesToCopy); buffer.AddRange(afewmorebytes); As my List is the List<byte> variety, I'd prefer to avoid a loop that copies byte by byte. 回答1: The List<T>(IEnumerable<T>) constructor will
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