OQL stands for "Object Query Language". It is defined by the Object Data Management Group (ODMG).
Questions tagged [oql]
87 questions
3
votes
1 answer
Cannot access the value of a StringBuilder in a heap dump in VisualVM
I am willing to write the value of a large StringBuilder with index 827 to disk. I am trying to do that using the following OQL:
map(heap.objects('java.lang.StringBuilder'),
function(it, index) {
if (index == 827.0) {
var writer = new…
Ivaylo Toskov
- 31
- 3
3
votes
1 answer
Given a hashmap's object id, get the field of the keys in a hashmap
I have loaded a heap dump into map. I have found the hashmap with leaking objects. How can get the fields of the keys in that hashmap? I suspect I have multiple copies of the same object in the map with names like joseph_0001, joseph_0002, ...,…
joseph
- 2,429
- 1
- 22
- 43
3
votes
2 answers
How to sort strings in OQL
I have tried:
select sort(obj.displayName, 'lhs < rhs') from my.org.BusinessClass obj
and
select sort(obj.displayName, 'lhs.toString() < rhs.toString()') from my.org.BusinessClass obj
Both give me character array results, but none of them are…
joseph
- 2,429
- 1
- 22
- 43
3
votes
1 answer
OQL syntax to refer to an object?
I find required objects in visualvm v1.3.8:
filter(heap.objects("java.lang.String"), "/hibernate\\.ejb\\.naming/(it.toString())")
they shown as:
java.lang.String#32669 - hibernate.ejb.naming_strategy_delegator
java.lang.String#34021 -…
gavenkoa
- 45,285
- 19
- 251
- 303
3
votes
1 answer
VisualVM 1.3.8 OQL - TypeError: [RegExp /java.lang./] is not a function
When executing below OQL, it gives TypeError: [RegExp /java.lang./] is not a function
select filter(heap.classes(), "/java.lang./(it.name)")
Should that work? Refer to OQL all instances from a package
Also, may I know if OQL is a "standard" for…
Lewis Wong
- 269
- 1
- 3
- 17
3
votes
3 answers
OQL all instances from a package
Is it possible in OQL to retrieve all the objects that belongs to a package? Or can I query with wildcards?
As @haridsv suggested I tried:
SELECT * from "com.example.*"
and
SELECT a from "com\.example\..*"
but in VisualVM it complaints that no…
ssedano
- 8,322
- 9
- 60
- 98
3
votes
1 answer
How to do embedded query using OQL in MAT Eclipse
I can get all Thread objects by using query as below
SELECT OBJECTS dominators(s) FROM java.lang.Thread s
then if I want to do further analysis of the returned result objects, the OQL I think should be like below:
SELECT * from (SELECT OBJECTS…
Y.Huang
- 119
- 2
- 11
2
votes
1 answer
Why is usage of javascript within visualvm (jhat?) oql sometimes confusing?
I am interested in knowing why visualvm OQL has a problem with the following statement:
select filter(heap.objects("java.util.HashMap"), isTrue(it));
function isTrue(object) {
return true;
}
Exception is:
javax.script.ScriptException:…
PineForest
- 75
- 1
- 9
2
votes
2 answers
Is there any way to get unreachable objects using OQL in mat?
I can query all the instances of com.google.common.cache.LocalCache$StrongAccessWriteEntry
in mat using OQL:
SELECT * FROM com.google.common.cache.LocalCache$StrongAccessWriteEntry
I've turned on Keep unreachable objects in mat. So the result…
Searene
- 25,920
- 39
- 129
- 186
2
votes
0 answers
Java heap analysis with OQL/VisualVM: find path from indirect referrer to referee?
I am trying to find the first path found from an object to some indirect referree.
The following code is what I came up with:
var debug = [];
//set referrer and target
var referrerObj = heap.findObject("815262352");
var targetObj =…
Tom
- 8,536
- 31
- 133
- 232
2
votes
1 answer
VisualVM OQL: how to search for primitive float values rather than actual Float instances?
I am wondering how one can search for all primitive float values that match a certain number.
When doing something like:
select n from java.lang.Float n where n.value == 1.00
Only the Float class instances are being found. The application I am…
Tom
- 8,536
- 31
- 133
- 232
2
votes
1 answer
How can I see the higher up object that uses the high count instances?
I'm using VisualVM and JProfiler to try and find a memory leak culprit.
There's a PoolThreadCache class that has the biggest number of instances.
Is there a way to see the call trace of the object usage? Something like…
osmingo
- 994
- 1
- 8
- 16
2
votes
0 answers
Java OQL find paths between two objects
With that Spring Boot auto-configuration and a lot of jars under the umbrella I had many contexts loaded and my configuration somehow ignored.
I made heapdump and would like to find paths between two known objects. That helps me to identify what…
gavenkoa
- 45,285
- 19
- 251
- 303
2
votes
2 answers
How to save the VisualVM OQL result directly into file?
My query results in millions of rows. I have already modified visualvm.conf
-J-DOQLController.limitResults=1000000
Currently, as a workaround I run the query, and copy and paste the result to a file. However, the result puts a lot of strain on my…
joseph
- 2,429
- 1
- 22
- 43
2
votes
1 answer
How to find the oldest instances on the heap using OQL
I'm trying to identify a memory leak using visualvm. I found some candidates by comapring snapshots, but since there are too many of these, I would like to narrow the search by locating the oldest instances on the heap. Is there a way using OQL to…
Shachar
- 21
- 2