Hi,
I was exploring BaseX for my XML based product. I was wondering whether there is Prepared Statement Like facility incorporated in BaseX,
With the same QueryProcessor instance, is it possible to execute it multiple times with different binding values for given variable.
I am executing following code.
QueryProcessor pr = new QueryProcessor("declare variable $a external ; $a",context); pr.context(itr); pr.bind("a","ABC"); Resultfinalr=pr.execute(); System.out.println("Final Execution Result 1 ::" + finalr); // rebinding $a with different value pr.bind("a", "XYZ"); Result out1 = pr.execute(); System.out.println("Final Execution Result 2 ::" + out1);
*******************************************************************************
I am getting "ABC" when I am executing second time. I need this because I would be executing the same query multiple times.
Thanks Anky
Hi Ankit,
I was exploring BaseX for my XML based product. I was wondering whether there is Prepared Statement Like facility incorporated in BaseX,
With the same QueryProcessor instance, is it possible to execute it multiple times with different binding values for given variable.
We are working on caching precompiled XQuery expressions; for now, you need to create new QueryProcessor instances. In practice, however, this rarely leads to problems, because QueryProcessor instances are very light-weight. The following BaseX call creates 100,000 instances of the QueryProcessor, it takes around 2 seconds:
basex -V -r100000 "1"
Parsing: 0.01 ms (avg) Compiling: 0.0 ms (avg) Evaluating: 0.0 ms (avg) Printing: 0.01 ms (avg) Total Time: 0.02 ms (avg)
Obviously, the query "1" is very simple, but usually, parsing only gets relevant if the queries to be parsed take many KBs or even MBs (such as can be the case in RESTXQ applications).
Best, Christian
Hi,
That's great , thank you very much Appreciate your prompt response. Hoping caching functionality will be added in the next release.
In my queries I am also including a module function library in each of my xqueries, so is there a way I can directly set the compiled module function library for all the QueryProcessor instance ,instead of adding library every time instance gets created.
Thanks Anky
On 23 January 2015 at 16:13, Christian Grün christian.gruen@gmail.com wrote:
Hi Ankit,
I was exploring BaseX for my XML based product. I was wondering whether there is Prepared Statement Like facility incorporated in BaseX,
With the same QueryProcessor instance, is it possible to execute it
multiple
times with different binding values for given variable.
We are working on caching precompiled XQuery expressions; for now, you need to create new QueryProcessor instances. In practice, however, this rarely leads to problems, because QueryProcessor instances are very light-weight. The following BaseX call creates 100,000 instances of the QueryProcessor, it takes around 2 seconds:
basex -V -r100000 "1"
Parsing: 0.01 ms (avg) Compiling: 0.0 ms (avg) Evaluating: 0.0 ms (avg) Printing: 0.01 ms (avg) Total Time: 0.02 ms (avg)
Obviously, the query "1" is very simple, but usually, parsing only gets relevant if the queries to be parsed take many KBs or even MBs (such as can be the case in RESTXQ applications).
Best, Christian
Hi Ankit,
In my queries I am also including a module function library in each of my xqueries, so is there a way I can directly set the compiled module function library for all the QueryProcessor instance ,instead of adding library every time instance gets created.
I guess you are using the import module statement of XQuery? That's the only way to do it (but it will only be parsed once per call). However, if you copy your module to the repository, you won't have to specify the file path. I invite you to check out our documentation on the XQuery repository [1].
Regarding your request of compiling the module, I would be interested to hear if you have already done some benchmarking in order to find out how much time is spent for parsing the module?
Best, Christian
[1] http://docs.basex.org/wiki/Repository
Thanks Anky
On 23 January 2015 at 16:13, Christian Grün christian.gruen@gmail.com wrote:
Hi Ankit,
I was exploring BaseX for my XML based product. I was wondering whether there is Prepared Statement Like facility incorporated in BaseX,
With the same QueryProcessor instance, is it possible to execute it multiple times with different binding values for given variable.
We are working on caching precompiled XQuery expressions; for now, you need to create new QueryProcessor instances. In practice, however, this rarely leads to problems, because QueryProcessor instances are very light-weight. The following BaseX call creates 100,000 instances of the QueryProcessor, it takes around 2 seconds:
basex -V -r100000 "1"
Parsing: 0.01 ms (avg) Compiling: 0.0 ms (avg) Evaluating: 0.0 ms (avg) Printing: 0.01 ms (avg) Total Time: 0.02 ms (avg)
Obviously, the query "1" is very simple, but usually, parsing only gets relevant if the queries to be parsed take many KBs or even MBs (such as can be the case in RESTXQ applications).
Best, Christian
Hi,
These are the benchmarking result.
basex -V -r100000 "import module 'http://www.xyz.org/2008/function/ins' at 'file:/C:/avc/FUNCTION_LIBRARY.xq';'a'" a Query: import module 'http://www.xyz.org/2008/function/ins' at 'file:/C:/avc/FUNCTION_LIBRARY.xq';'a'
Parsing: 2.71 ms (avg) Compiling: 0.0 ms (avg) Evaluating: 0.0 ms (avg) Printing: 0.01 ms (avg) Total Time: 2.73 ms (avg)
Hit(s): 1 Item Updated: 0 Items Printed: 1 Byte Read Locking: none Write Locking: none
Query executed in 2.73 ms (avg).
I have one more doubt regarding module compilation. Are the modules compiled lazily ?.
On 23 January 2015 at 17:21, Christian Grün christian.gruen@gmail.com wrote:
Hi Ankit,
In my queries I am also including a module function library in each of
my
xqueries, so is there a way I can directly set the compiled module function library for all the QueryProcessor instance ,instead of adding library every time instance gets created.
I guess you are using the import module statement of XQuery? That's the only way to do it (but it will only be parsed once per call). However, if you copy your module to the repository, you won't have to specify the file path. I invite you to check out our documentation on the XQuery repository [1].
Regarding your request of compiling the module, I would be interested to hear if you have already done some benchmarking in order to find out how much time is spent for parsing the module?
Best, Christian
[1] http://docs.basex.org/wiki/Repository
Thanks Anky
On 23 January 2015 at 16:13, Christian Grün christian.gruen@gmail.com wrote:
Hi Ankit,
I was exploring BaseX for my XML based product. I was wondering
whether
there is Prepared Statement Like facility incorporated in BaseX,
With the same QueryProcessor instance, is it possible to execute it multiple times with different binding values for given variable.
We are working on caching precompiled XQuery expressions; for now, you need to create new QueryProcessor instances. In practice, however, this rarely leads to problems, because QueryProcessor instances are very light-weight. The following BaseX call creates 100,000 instances of the QueryProcessor, it takes around 2 seconds:
basex -V -r100000 "1"
Parsing: 0.01 ms (avg) Compiling: 0.0 ms (avg) Evaluating: 0.0 ms (avg) Printing: 0.01 ms (avg) Total Time: 0.02 ms (avg)
Obviously, the query "1" is very simple, but usually, parsing only gets relevant if the queries to be parsed take many KBs or even MBs (such as can be the case in RESTXQ applications).
Best, Christian
These are the benchmarking result.
Thanks. The overhead of 2-3 ms could surely be reduced once the modules will be precompiled. Does the current overhead represent a bottleneck in your scenario?
I have one more doubt regarding module compilation. Are the modules compiled lazily ?.
Library modules are parsed every time they are imported.
C.
On 23 January 2015 at 17:21, Christian Grün christian.gruen@gmail.com wrote:
Hi Ankit,
In my queries I am also including a module function library in each of my xqueries, so is there a way I can directly set the compiled module function library for all the QueryProcessor instance ,instead of adding library every time instance gets created.
I guess you are using the import module statement of XQuery? That's the only way to do it (but it will only be parsed once per call). However, if you copy your module to the repository, you won't have to specify the file path. I invite you to check out our documentation on the XQuery repository [1].
Regarding your request of compiling the module, I would be interested to hear if you have already done some benchmarking in order to find out how much time is spent for parsing the module?
Best, Christian
[1] http://docs.basex.org/wiki/Repository
Thanks Anky
On 23 January 2015 at 16:13, Christian Grün christian.gruen@gmail.com wrote:
Hi Ankit,
I was exploring BaseX for my XML based product. I was wondering whether there is Prepared Statement Like facility incorporated in BaseX,
With the same QueryProcessor instance, is it possible to execute it multiple times with different binding values for given variable.
We are working on caching precompiled XQuery expressions; for now, you need to create new QueryProcessor instances. In practice, however, this rarely leads to problems, because QueryProcessor instances are very light-weight. The following BaseX call creates 100,000 instances of the QueryProcessor, it takes around 2 seconds:
basex -V -r100000 "1"
Parsing: 0.01 ms (avg) Compiling: 0.0 ms (avg) Evaluating: 0.0 ms (avg) Printing: 0.01 ms (avg) Total Time: 0.02 ms (avg)
Obviously, the query "1" is very simple, but usually, parsing only gets relevant if the queries to be parsed take many KBs or even MBs (such as can be the case in RESTXQ applications).
Best, Christian
Hi,
I tried similar thing using java. It is taking 86 ms for parsing.
QueryProcessor mod = new QueryProcessor("import module ' http://www.xyz.org/2008/function/ins' at 'file:/C:/avc/FUNCTION_ LIBRARY.xq';'a' ", context); long time=System.currentTimeMillis(); mod.parse(); System.out.println(" Time ::" + (System.currentTimeMillis() - time));
Output :: Time :: 86
Does the current overhead represent a bottleneck in your scenario?
We have a scenario where we need to execute queries thousand times for each user, that will hamper the performance.
Thanks Anky
On 23 January 2015 at 17:56, Christian Grün christian.gruen@gmail.com wrote:
These are the benchmarking result.
Thanks. The overhead of 2-3 ms could surely be reduced once the modules will be precompiled. Does the current overhead represent a bottleneck in your scenario?
I have one more doubt regarding module compilation. Are the modules
compiled
lazily ?.
Library modules are parsed every time they are imported.
C.
On 23 January 2015 at 17:21, Christian Grün christian.gruen@gmail.com wrote:
Hi Ankit,
In my queries I am also including a module function library in each
of
my xqueries, so is there a way I can directly set the compiled module function library for all the QueryProcessor instance ,instead of adding library every time instance gets created.
I guess you are using the import module statement of XQuery? That's the only way to do it (but it will only be parsed once per call). However, if you copy your module to the repository, you won't have to specify the file path. I invite you to check out our documentation on the XQuery repository [1].
Regarding your request of compiling the module, I would be interested to hear if you have already done some benchmarking in order to find out how much time is spent for parsing the module?
Best, Christian
[1] http://docs.basex.org/wiki/Repository
Thanks Anky
On 23 January 2015 at 16:13, Christian Grün <
christian.gruen@gmail.com>
wrote:
Hi Ankit,
I was exploring BaseX for my XML based product. I was wondering whether there is Prepared Statement Like facility incorporated in BaseX,
With the same QueryProcessor instance, is it possible to execute it multiple times with different binding values for given variable.
We are working on caching precompiled XQuery expressions; for now,
you
need to create new QueryProcessor instances. In practice, however, this rarely leads to problems, because QueryProcessor instances are very light-weight. The following BaseX call creates 100,000 instances of the QueryProcessor, it takes around 2 seconds:
basex -V -r100000 "1"
Parsing: 0.01 ms (avg) Compiling: 0.0 ms (avg) Evaluating: 0.0 ms (avg) Printing: 0.01 ms (avg) Total Time: 0.02 ms (avg)
Obviously, the query "1" is very simple, but usually, parsing only gets relevant if the queries to be parsed take many KBs or even MBs (such as can be the case in RESTXQ applications).
Best, Christian
I tried similar thing using java. It is taking 86 ms for parsing.
This is most probably due to the startup of the JVM. I would be surprised if you shouldn't get similar times as shown on command line (btw, you'll get more exact measurements by using System.nanoTime()).
We have a scenario where we need to execute queries thousand times for each user, that will hamper the performance.
I'll be interested to find out how much of the total time of your application will be spent for parsing the query, or if it's not other components that will be predominating. Feel free to send me some profiling data (e.g. generated via the JVM flags -Xrunhprof:cpu=samples) once you have it running.
basex-talk@mailman.uni-konstanz.de
-
ankit kumar -
Christian Grün