This patch implements the same function as Hive UDF get_json_object.
We reuse RapidJson to parse the json string. In order to track the
memory used in RapidJson, we wrap FunctionContext into an allocator.
get_json_object accepts two parameters: a json string and a selector
(json path). We parse the json string into a Document tree and then
perform BFS according to the selector. For example, to process
get_json_object('[{\"a\":1}, {\"a\":2}, {\"a\":3}]', '$[*].a'),
we first perform '$[*]' to extract all the items in the root array.
Then we get a queue consists of {a:1},{a:2},{a:3} and perform '.a'
selector on all values in the queue. The final results is 1,2,3 in the
queue. As there're multiple results, they should be encapsulated into
an array. The output results is a string of '[1,2,3]'.
More examples can be found in expr-test.cc.
Test:
* Add unit tests in expr-test
* Add e2e tests in exprs.test
* Add tests in test_alloc_fail.py to check handling of out of memory
Change-Id: I6a9d3598cb3beca0865a7edb094f3a5b602dbd2f
Reviewed-on: http://gerrit.cloudera.org:8080/10950
Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
We need to check for AllocateLocal() returning NULL. CopyFrom() takes
care of that for us. Also adjust a few other places in the code base
that didn't have the check.
The new test reproduces the crash, but in order to get this test file to
execute, I had to move the xfail to be a function decorator. Apparently
xfail as a statement causes the test to not run at all. We should run
all of these queries even if they are non-determistic to at least verify
that impalad does not crash.
Change-Id: Iafefef24479164cc4d2b99191d2de28eb8b311b6
Reviewed-on: http://gerrit.cloudera.org:8080/6761
Reviewed-by: Dan Hecht <dhecht@cloudera.com>
Tested-by: Impala Public Jenkins
test_alloc_fail_update() aims to stress memory allocation
failure in the Update(), Serialize() and/or Finalize() functions
of UDAs. However, this test included some UDFs which allocated
memory in their Init() functions and not during their Update()
functions. This change removes those UDFs from the test.
Change-Id: I1ecc7e838e34ebc9ea3c878fee8ea2497b5fa23e
Reviewed-on: http://gerrit.cloudera.org:8080/2005
Reviewed-by: Matthew Jacobs <mj@cloudera.com>
Reviewed-by: Dan Hecht <dhecht@cloudera.com>
Tested-by: Internal Jenkins
FunctionContext::Allocate(), FunctionContextImpl::AllocateLocal()
and FunctionContext::Reallocate() allocate memory without taking
memory limits into account. The problem is that these functions
invoke FreePool::Allocate() which may call MemPool::Allocate()
that doesn't check against the memory limits. This patch fixes
the problem by making these FunctionContext functions check for
memory limits and set an error in the FunctionContext object if
memory limits are exceeded.
An alternative would be for these functions to call
MemPool::TryAllocate() instead and return NULL if memory limits
are exceeded. However, this may break some existing external
UDAs which don't check for allocation failures, leading to
unexpected crashes of Impala. Therefore, we stick with this
ad hoc approach until the UDF/UDA interfaces are updated in
the future releases.
Callers of these FunctionContext functions are also updated to
handle potential failed allocations instead of operating on
NULL pointers. The query status will be polled at various
locations and terminate the query.
This patch also fixes MemPool to handle the case in which malloc
may return NULL. It propagates the failure to the callers instead
of continuing to run with NULL pointers. In addition, errors during
aggregate functions' initialization are now properly propagated.
Change-Id: Icefda795cd685e5d0d8a518cbadd37f02ea5e733
Reviewed-on: http://gerrit.cloudera.org:8080/1445
Reviewed-by: Michael Ho <kwho@cloudera.com>
Tested-by: Internal Jenkins
