storage

问题 Is my general understanding that a typical database management systems bypass file system correct? I understand that they manage their own space on disk and they write actual data and index systems like B tree directly into disk blocks bypassing any intermediate help from file system. This assumes that root would provide the database user permission to directly read and write from disk blocks. In Linux, this is still easier as disk can be treated as a file. Any pointer to real case studies

问题 Is my general understanding that a typical database management systems bypass file system correct? I understand that they manage their own space on disk and they write actual data and index systems like B tree directly into disk blocks bypassing any intermediate help from file system. This assumes that root would provide the database user permission to directly read and write from disk blocks. In Linux, this is still easier as disk can be treated as a file. Any pointer to real case studies

问题 In this question someone asked for ways to display disk usage in Linux. I'd like to take this one step further down the cli-path... how about a shell script that takes the output from something like a reasonable answer to the previous question and generates a graph/chart from it (output in a png file or something)? This may be a bit too much code to ask for in a regular question, but my guess is that someone already has a oneliner laying around somewhere... 回答1: I would recommend munin. It is

问题 I am using Angular 2 and Typescript and wanted to save the user object like a global variable so it hasn't to be retrieved multiple times. I found the session storage and now save the user object there. Do you think it is good practice to store it there or is the data too sensitve? If so, what other kind of cache could I use? Here is the code I use right now: user.service.ts: getProfile() { let cached: any; if (cached = sessionStorage.getItem(this._baseUrl)) { return Observable.of(JSON.parse

问题 Is it possible to read and write to a local sqlite file from a chrome packaged app? I currently already read and write to a json file with app data that is locally stored on the harddrive but I also want to be able to do this with a sqlite database. I need it to be local and not on drive since I will interact with it from other (non chrome) processes as well. And even loading the file from drive (using sync filesystem instead of filesystem), I have no clue how to go about accessing a sqlite

问题 I have Jenkins cloning the Git repository at ssh://user@ip/repo/ and it all works fine, but I need to login with a password, which Jenkins doesn't support. Is there a way to login with the password in the URL? Security is not an issue for me. It should end up being, and I thought it was this at first: ssh://user:pass@ip/repo/ but it doesn't work. Thanks! Update #1: The git repo is on the same server. 回答1: There are two reason why SSH ask you for a password: the public key isn't found on the

问题 How Does HDFS store data? I want to store huge files in a compressed fashion. E.g : I have a 1.5 GB of file, with default replication factor of 3. It requires (1.5)*3 = 4.5 GB of space. I believe currently no implicit compression of data takes place. Is there a technique to compress the file and store it in HDFS to save disk space ? 回答1: HDFS stores any file in a number of 'blocks'. The block size is configurable on a per file basis, but has a default value (like 64/128/256 MB) So given a

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 7 years ago . I need to prepare a storage for hundreds of millions of images (now I have 70 millions and this number is still growing). Each image

问题 We have a very large historical table that contains a column with at most 500 UTF8 characters, and the disk space grows really fast! We're having at least 2 million rows a day... and we were wondering which would do a better job (mostly in storage but in performance as well)? TEXT or VARCHAR(512)? 回答1: VARCHAR is probably preferable in your case from both the storage and performance perspective. View this oft-reposted article. 回答2: This is useful information; I think in general, the answer is

问题 I'm trying to make a Chrome extension. For that extension, I need some info that is dynamically created, but I want that data to be added even later on (on a different page). This is some sort of data that i want to be always accessible (when the plugin runs): var villages = new Array(); villages[0][0] = "village1"; villages[0][1] = "1325848"; villages[1][0] = "village2"; villages[1][1] = "8744351"; villages[2][0] = "village3"; villages[2][1] = "8952187"; As you can see, the array is multi