N1QL query does not use the expected index - couchbase

I am trying to create a couchbase N1QL query that will use a specific index.
This is my index:
CREATE INDEX index_progressTest ON testbucket(payload.type, payload.display, payload.status, meta(testbucket).id) where payload.type = "Test" AND payload.display = true AND payload.status != "IN_PROGRESS" using GSI;
And this is my query (I use explain to see which index it will use):
EXPLAIN SELECT meta(jmbucket).id FROM testbucket WHERE payload.type = "Test" AND payload.display = true AND payload.status != "IN_PROGRESS";
But it seems that the query will not use my index.
If I remove the last part of the "WHERE" clause from both the index and query, then everything works fine.
What should I do to fix it?
Thanks!

This is fixed in Couchbase 4.5.
If you want to use 4.1, remove this from your index:
AND payload.status != "IN_PROGRESS"

Remember that Couchbase is Case Sensitive. Make sure that the columns specified in your Create Index script matches the case of the elements in the document. I found this out the hard way. #lessonlearned

Related

Use where in Rails and check only first element

Is it possible to, using only Rails, check first element in a join table?
Should be the same as:
User.includes(:articles).select {|u| !u.articles.first.voided? }
But with Rails 'where' statement is:
where("articles.first.status != 'voided'")
If your db is postgres and you can add first agg function than it should look like User.select('users.*').includes(:articles).group('users.id').where("FIRST(articles.status) != 'voided'")
Article.includes(:user).first.status
will give you first article status.try it pls

Trick to use variable in match against mysql

Please first read my question,and then you will find out it is not a duplicate of other question.
I'm using sphinx search for 98% of search,but need to use match against for just one query.
As we know from mysql documentation that AGAINST only takes string.The search string must be a literal string, not a variable or a column name.
But I have found this link http://bugs.mysql.com/bug.php?id=66573 ,which says it is possible.But I'm not sure how to use that in my case.
Here is my code
$sqli="SELECT busi_title,category FROM `user`.`user_det`";
$queryi=mysqli_query($connecti,$sqli);
if(mysqli_num_rows($queryi)>0){
while($rowi=mysqli_fetch_assoc($queryi)){
$busi_title=$rowi['busi_title'];
$category=$rowi['category'];
}
}else{
echo "OH NO";
}
$sqlj="SELECT * FROM `user`.`user_det` WHERE MATCH(student) AGAINST('$busi_title','$category')";
$queryj=mysqli_query($connecti,$sqlj);
if(mysqli_num_rows($queryj)>0){
..............................
..............................
}else{
foreach ( $res["matches"] as $doc => $docinfo ) {
................................
...............................
}
}
MATCH() AGAINST() is giving error,as it supposed to be.How to use that trick of that link in this case.I don't know the use of #word:= of that link.
Thanks in advance.
That link doesn't show a trick to get around a limitation of MySQL. It's a bug report demonstrating an incorrect statement in the MySQL documentation. The statement in the documentation has now been corrected.
The reason you're getting an error is because you're sending two parameters to AGAINST and it only accepts one. You can use a MySQL variable in AGAINST which is what the bug report is about, but this has nothing to do with the PHP variable that you're using.
EDIT
Upon reading your response, I rather suspect that you have your syntax backwards.
SELECT * FROM `user`.`user_dets` WHERE MATCH(busi_title, category) AGAINST('student')
But note this from the documentation:
The MATCH() column list must match exactly the column list in some FULLTEXT index definition for the table, unless this MATCH() is IN BOOLEAN MODE. Boolean-mode searches can be done on nonindexed columns, although they are likely to be slow.
If you don't have a Fulltext index, you'll actually want this:
SELECT * FROM `user`.`user_dets` WHERE `busi_title` LIKE '%student%' OR `category` LIKE '%student%'
When they say "The search string must be a literal string, not a variable or a column name" does not mean you cannot use variable to create your Query String.
So it is OK to make your query very simple.
Your WHERE could be this:
WHERE `student` = $busi_title OR `student` = $category

Creating an OR statement using existing conditions hash

I am working on a problem where I need to add an OR clause to a set of existing conditions. The current conditions are built in a hash in a method and at the end, they are used in the where clause. Here is a simplified example:
...
conds.merge!({:users => {:archived => false}})
Model.where(conds)
I am trying to add an OR clause to the current set of conditions so it would be something like '(conditions) OR new_condition'. I'd like to add the OR statement without converting each addition to the conds hash into a string. That would be my last option. I was hoping someone has done something like this before (without using Arel). I seem to recall in Rails 2 there was a way to parse a conditions hash using a method from the model (something like Model.some_method(conds) would produce the where clause string. Maybe that would be a good option to just add the OR clause on to that string. Any ideas are appreciated. Thank you for your help!
I found a way to do what I needed. Instead of changing all of the conditions that I am building, I am parsing the conditions to SQL using sanitize_sql_for_conditions. This is a private method in ActiveRecord, so I had to put a method on the model to allow me to access it. Here is my model method:
def self.convert_conditions_hash_to_sql(conditions)
self.sanitize_sql_for_conditions(conditions)
end
So, once I convert my conditions to text, I can add my OR clause (along with the appropriate parentheses) to the end of the original conditions. So, it would go something like this:
Model.where('(?) OR (model.type = ? AND model.id IN(?))', Model.convert_conditions_hash_to_sql(conds), model_type, model_id_array)

DBIx::Class update only one row

I am using DBIx::Class and I would like to only update one row in my table. Currently this is how I do it:
my $session = my_app->model("DB::Session")->find(1);
$session->update({done_yn=>'y',end_time=>\'NOW()'});
It works, but the problem is that when it does find to find the row, it does this whole query:
SELECT me.id, me.project_id, me.user_id, me.start_time, me.end_time, me.notes, me.done_yn FROM sessions me WHERE ( me.id = ? ): '8'
Which seems a bit much when all I want to do is update a row. Is there anyway to update a row without having to pull the whole row out of the database first? Something like this is what I am looking for:
my_app->model("DB::Session")->update({done_yn=>'y',end_time=>\'NOW()'},{id=>$id});
Where $id is the WHERE id=? part of the query. Does anyone know how to do this? Thanks!
You can run update on a restricted resultset which only matches this single row:
my_app->model("DB::Session")->search_rs({ id=> 1 })->update({done_yn=>'y',end_time=>\'NOW()'});
I suggest you use a DateTime->now object instead of literal SQL for updating the end_time column because it uses the apps servers date and time instead of the database servers and makes your schema more compatible with different RDBMSes.
Do you have a check if the row was found to prevent an error in case it wasn't?
You might want to use update_or_create instead.
You could use the "columns" attribute:
my $session = my_app->model("DB::Session")->find(1, {columns => "id"});

linq-to-sql How can I get a few rows that don't match my existing rows?

I have a few rows of data pulled into business objects via linq-to-sql from large tables.
Now I want to get a few rows that don't match to test my comparison functions.
Using what I thought would work I get a NotSupportedException:
Local sequence cannot be used in LINQ to SQL implementation of query operators except the Contains() operator.
Here's the code:
//This table has a 2 field primary key, the other has a single
var AllNonMatches = from c in dc.Acaps
where !Matches.Rows.Any((row) => row.Key.Key == c.AppId & row.Key.Value == c.SeqNbr)
select c;
foreach (var item in AllNonMatches.Take(100)) //Exception here
{}
The table has a compound primary key: AppId and SeqNbr.
The Matches.Rows is defined as a dictionary of keyvaluepair(appid,seqnbr).
and the local sequence it is referring to appears to be the local dictionary.
Could you provide more information on the structure and the name(s) of the table(s) plz?
Not sure what you're trying to do...
edit:
Ok.. I think I get it now...
It appears you can't merge/join local tables (dictionary) with a SQL table.
If you can, I'm afraid I don't know how to do it.
The simplest solution I can think of is to put those results in a table ("Match" for instance) with foreign keys related to your table "Acaps" and then use linq-to-sql, like:
var AllNonMatches = dc.Acaps.Where(p=>p.Matchs==null).Take(100).ToList();
Sorry I couldn't come up with any better =(
What about this:
var AllNonMatches = from c in dc.Acaps
where !(Matches.Rows.ContainsKey(c.AppId) && Matches.Rows.ContainsValue(c.SeqNbr))
select c;
That will work fine. I have also used a bitwise AND operator (&&) - I think thats the right term to help improve performance over the standard AND operator.