![]() Sometimes, a variable needs to be shared across tasks, or between tasks and the driver program. By default, when Spark runs a function in parallel as a set of tasks on different nodes, it ships a copy of each variable used in the function to each task. Finally, RDDs automatically recover from node failures.Ī second abstraction in Spark is shared variables that can be used in parallel operations. Users may also ask Spark to persist an RDD in memory, allowing it to be reused efficiently across parallel operations. RDDs are created by starting with a file in the Hadoop file system (or any other Hadoop-supported file system), or an existing Scala collection in the driver program, and transforming it. The main abstraction Spark provides is a resilient distributed dataset (RDD), which is a collection of elements partitioned across the nodes of the cluster that can be operated on in parallel. One of its array of neat tricks is the ability to generate reverse date notation for file names, and to include automatically incremented numbering to distinguish files with otherwise identical names.Įven if you don't intend to use the software, it's worth searching and downloading the FileCenter User Guide for its excellent notes on smart ways to name files.įor decades, software engineers have used small text files as a way to leave notes for later visitors to a folder of materials.At a high level, every Spark application consists of a driver program that runs the user’s main function and executes various parallel operations on a cluster. We've often praised Lucion's peerless paperless office software FileCenter. If you can't see why, just give it a try. Reverse notation ensures that a computer lists the folder contents in true date order. ![]() Unless you use reverse notation for the date format, Windows will place all the documents dated the first of any month or year ahead of all the documents dated the second of any month or year, and so on. With the date hard coded in the file name, your digital documents will hold their order even if Windows gives the files new time stamps because of a trivial contents change or a copy operation. If you want to list a folder of files in true date order, start their names with "" or as the case may be, not "01-02-2018". But if you like the idea of an easy way to cut costs and accelerate transactions, taking the initiative and getting your own documents in order is a great start. If you don't mind paying extra charges for professional time, or don't much care whether the counterparty in your deal has to waste effort identifying and ordering your due diligence documents, fine. If there are 20 documents, their order will be 1, 11, 12, etc, with 2 listed only after 19. Otherwise, a PC will order everything starting with a "1" ahead of anything beginning with "2". If you do sequence files using numbers, be sure to pad the digits with leading zeroes ie "001", "002" and so on. The alternative is to wade into the jumble file by file, try to work out what everything is, and rename and sequence it yourself in a quest for clarity and order. If you really mean to inform them of "ABC Ltd share transfers – June 2017" and "ASX Announcements – February 2018", why not name the e-docs so?īetter still, if digital docs should be read in sequence, why not number their file names?Īs an adviser, it's really helpful if linking to a Dropbox folder where the starting point is labelled 001 and the rest of the files follow suit. ![]() Next time you're mailing multiple attachments, or sharing a stack of files in a Dropbox folder, think about how much sense "transfers.xls" and "sts mkt.docx" will make to your correspondent. When a client sends an adviser, or one transaction party sends another, a bunch of poorly identified data files, why should anyone be surprised that confusion and extra cost follow?Īgreed, there's no national standard for naming data files, but is that an excuse for dumping a jumble on your accountant, lawyer or business partner, leaving them to work out what's what? Next time you send a load of digital files to a lawyer or expert that charges by the hour, think about how you name the files, so they don't waste time. And its file date could be downright misleading, possibly nothing more than the last time it was copied. It might open to reveal a balance sheet or last weekend's racing tips. At least a paper invoice looks like an invoice and its date is normally obvious.īut a digital file looks like … a digital file. Accountants once complained when clients dumped a shoebox full of invoices and receipts on their desk, expecting a miraculous transformation into a tax return.īut at least you can sort paper by hand and eye.
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