To expand on David's suggestion a bit, running this:
xdmp:estimate(
cts:search(
/book,
cts:and-query((
cts:element-value-query(xs:QName("title"),"New Book"),
cts:element-value-query(xs:QName("price"),"100"),
cts:directory-query("/localhost/")
)))
)
and this:
fn:count(
cts:uris(
'',
(),
cts:and-query((
cts:element-value-query(xs:QName("title"),"New Book"),
cts:element-value-query(xs:QName("price"),"100"),
cts:directory-query("/localhost/")
)))
)
will both give results based on index resolution. (Understanding the Search
Process<https://docs.marklogic.com/guide/performance/unfiltered#id_13165>) The
query passed to cts:uris()<https://docs.marklogic.com/cts:uris#query> is always
evaluated unfiltered. At a glance, it looks like the only way that
xdmp:estimate<https://docs.marklogic.com/xdmp:estimate> might give you
inaccurate results is based on the first parameter to cts:search(), the /book.
If you changed that to fn:doc(), then the two queries above would be equivalent
but I'd expect xdmp:estimate() to run a lot faster. (I believe the universal
index will make the rest of the query accurate; someone please correct me if
I'm wrong.)
--
Dave Cassel
Vanguard Technical Manager
MarkLogic Corporation<http://www.marklogic.com/>
Cell: +1-484-798-8720
From: David Ennis <[email protected]<mailto:[email protected]>>
Reply-To: MarkLogic Developer Discussion
<[email protected]<mailto:[email protected]>>
Date: Tuesday, March 11, 2014 at 4:33 AM
To: MarkLogic Developer Discussion
<[email protected]<mailto:[email protected]>>
Subject: Re: [MarkLogic Dev General] Reg:Performance comparison for cts:search
and cts:uris
Hi.
Do you need the exact number? If not, then the solution with the best
performance is actually xdmp:estimate. This uses indexes and is not only
bazillions of times faster, but does not require the memory you need in your
samples. You can find documentation about the differences of fn:count and
xdmp:estimate on MarkLogic's website and decide which is better for which use.
As for you example, fn:count always counts what it is given. for your example,
it is likely faster because cts-uris gives back less information and everything
it gives back is in an index. the search may very well be reading abd
returning every result. larger result and possibly more disk reads (And
unpacking the packed data).
Kind Regards,
David Ennis
On 11 March 2014 10:25, priya dharshni
<[email protected]<mailto:[email protected]>> wrote:
Hi,
We are having millions of records in db.Now i want to query the entire
database based on few filters.For example,
i am having "/test/book1.xml","/test/book2.xml","/test/book3.xml" ...
"/test/bookn.xml"
<book>
<title>New Book</title>
<Author>Auth X</Author>
<price>100</price>
</book>
Now i have to fetch the count of uris whose title is "New Book" and
price=100.I tried with cts:search and cts:uris which gives me the same result.
But i would like to know on performance side which is the best approach.
count(cts:search(/book,cts:and-query((cts:element-value-query(xs:QName("title"),"New
Book"),cts:element-value-query(xs:QName("price"),"100")
,cts:directory-query("/localhost/")
)))
)
count(cts:uris('',(),cts:and-query((cts:element-value-query(xs:QName("title"),"New
Book"),cts:element-value-query(xs:QName("price"),"100")
,cts:directory-query("/localhost/")
)))
)
In profiling i found the number expression executed for cts:uris is less.Please
suggest which is the best approach when we apply the
cts:document-query,cts:and-query .
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