Databases
StackOverflow2013
Postsdbo
POwhy is sax parsing faster than dom parsing ? and how does stax work?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POwhy is sax parsing faster than dom parsing ? and how does stax work?
    primarykey
    data
    text
    <p>somewhat related to: <a href="https://stackoverflow.com/questions/3701265/libxml2-from-java">libxml2 from java</a></p> <p>yes, this question is rather long-winded - sorry. I kept is as dense as I felt possible. I bolded the questions to make it easier to peek at before reading the whole thing.</p> <p><strong>Why is sax parsing faster than dom parsing?</strong> The only thing I can come up with is that w/ sax you're probably ignoring the majority of the incoming data, and thus not wasting time processing parts of the xml you don't care about. IOW - after parsing w/ SAX, you can't recreate the original input. <strong>If you wrote your SAX parser so that it accounted for each and every xml node (and could thus recreate the original), then it wouldn't be any faster than DOM would it?</strong></p> <p>The reason I'm asking is that I'm trying to parse xml documents more quickly. I need to have access to the entire xml tree AFTER parsing. I am writing a platform for 3rd party services to plug into, so I can't anticipate what parts of the xml document will be needed and which parts won't. I don't even know the structure of the incoming document. This is why I can't use jaxb or sax. Memory footprint isn't an issue for me because the xml documents are small and I only need 1 in memory at a time. It's the time it takes to parse this relatively small xml document that is killing me. I haven't used stax before, but perhaps I need to investigate further because it might be the middle ground? <strong>If I understand correctly, stax keeps the original xml structure and processes the parts that I ask for on demand?</strong> In this way, the original parse time might be quick, but each time I ask it to traverse part of the tree it hasn't yet traversed, that's when the processing takes place?</p> <p>If you provide a link that answers most of the questions, I will accept your answer (you don't have to directly answer my questions if they're already answered elsewhere).</p> <p><strong>update: I rewrote it in sax and it parses documents on avg 2.1 ms. This is an improvement (16% faster) over the 2.5 ms that dom was taking, however it is not the magnitude that I (et al) would've guessed</strong></p> <p>Thanks</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USCommunity
    1. USandersonbd1
    plurals
    1. PL
      singulars
      1. LTLinked
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POwhy is sax parsing faster than dom parsing ? and how does stax work?
      1. This table or related slice is empty.
      1. VTDownMod
    2. VO
      singulars
      1. POwhy is sax parsing faster than dom parsing ? and how does stax work?
      1. This table or related slice is empty.
      1. VTDownMod
    3. VO
      singulars
      1. POwhy is sax parsing faster than dom parsing ? and how does stax work?
      1. USandersonbd1
      1. VTFavorite
    1. COI'd say the question of which is faster is irrelevant for your purposes, because you need to make arbitrary queries against the tree. Which means that you have to build some representation of the tree, and have some way to create queries against it. So either you use DOM/XPath, or you write your own equivalents.
      singulars
      1. POwhy is sax parsing faster than dom parsing ? and how does stax work?
      1. USAnon
    2. COI suspect, however, that your real issue is not SAX vs DOM per se, but how your system is configured and/or how you're accessing the data. It really shouldn't take that long to parse a "small" document using DOM (or one of the DOM equivalents). Have you quantified the difference (that you're seeing) between SAX and DOM?
      singulars
      1. POwhy is sax parsing faster than dom parsing ? and how does stax work?
      1. USAnon
    3. COI have quantified the DOM approach. small (approx. 300k) xml documents. The current implementation is using xerces-j and it takes about 2.5 ms per xml document on a 1.5 GHz machine. to quantify sax is somewhat dependent on how much of the xml you choose to keep around and what you do with it. you're right - I don't think sax will work for me - the question was more out of curiosity.
      singulars
      1. POwhy is sax parsing faster than dom parsing ? and how does stax work?
      1. USandersonbd1
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload