The Impala CatalogService manages the caching and dissemination of cluster-wide metadata.
The CatalogService combines the metadata from the Hive Metastore, the NameNode,
and potentially additional sources in the future. The CatalogService uses the
StateStore to broadcast metadata updates across the cluster.
The CatalogService also directly handles executing metadata updates request from
impalad servers (DDL requests). It exposes a Thrift interface to allow impalads to
directly connect execute their DDL operations.
The CatalogService has two main components - a C++ server that implements StateStore
integration, Thrift service implementiation, and exporting of the debug webpage/metrics.
The other main component is the Java Catalog that manages caching and updating of of all
the metadata. For each StateStore heartbeat, a delta of all metadata updates is broadcast
to the rest of the cluster.
Some Notes On the Changes
---
* The metadata is all sent as thrift structs. To do this all catalog objects (Tables/Views,
Databases, UDFs) have thrift struct to represent them. These are sent with each statestore
delta update.
* The existing Catalog class has been seperated into two seperate sub-classes. An
ImpladCatalog and a CatalogServiceCatalog. See the comments on those classes for more
details.
What is working:
* New CatalogService created
* Working with statestore delta updates and latest UDF changes
* DDL performed on Node 1 is now visible on all other nodes without a "refresh".
* Each DDL operation against the Catalog Service will return the catalog version that
contains the change. An impalad will wait for the statestore heartbeat that contains this
version before returning from the DDL comment.
* All table types (Hbase, Hdfs, Views) getting their metadata propagated properly
* Block location information included in CS updates and used by Impalads
* Column and table stats included in CS updates and used by Impalads
* Query tests are all passing
Still TODO:
* Directly return catalog object metadata from DDL requests
* Poll the Hive Metastore to detect new/dropped/modified tables
* Reorganize the FE code for the Catalog Service. I don't think we want everything in the
same JAR.
Change-Id: I8c61296dac28fb98bcfdc17361f4f141d3977eda
Reviewed-on: http://gerrit.ent.cloudera.com:8080/601
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Tested-by: Lenni Kuff <lskuff@cloudera.com>
Split out the encoder/type for parquet reader/writer. I think this puts us
in a better place to support future encodings.
On the tpch lineitem table, the results are:
Before:
BytesWritten: 236.45 MB
Per Column Sizes:
l_comment: 75.71 MB
l_commitdate: 8.64 MB
l_discount: 11.19 MB
l_extendedprice: 33.02 MB
l_linenumber: 4.56 MB
l_linestatus: 869.98 KB
l_orderkey: 8.99 MB
l_partkey: 27.02 MB
l_quantity: 11.58 MB
l_receiptdate: 8.65 MB
l_returnflag: 1.40 MB
l_shipdate: 8.65 MB
l_shipinstruct: 1.45 MB
l_shipmode: 2.17 MB
l_suppkey: 21.91 MB
l_tax: 10.68 MB
After:
BytesWritten: 198.63 MB (84%)
Per Column Sizes:
l_comment: 75.71 MB (100%)
l_commitdate: 8.64 MB (100%)
l_discount: 2.89 MB (25.8%)
l_extendedprice: 33.13 MB (100.33%)
l_linenumber: 1.50 MB (32.89%)
l_linestatus: 870.26 KB (100.032%)
l_orderkey: 9.18 MB (102.11%)
l_partkey: 27.10 MB (100.29%)
l_quantity: 4.32 MB (37.31%)
l_receiptdate: 8.65 MB (100%)
l_returnflag: 1.40 MB (100%)
l_shipdate: 8.65 MB (100%)
l_shipinstruct: 1.45 MB (100%)
l_shipmode: 2.17 MB (100%)
l_suppkey: 10.11 MB (46.14%)
l_tax: 2.89 MB (27.06%)
The table is overall 84% as big (i.e. 16% smaller). A few columns got marginally
bigger. If the file filled the 1 GB, I'd expect the overhead to decrease even
more.
The restructuring to use a virtual call doesn't seem to change things much and
will go away when we codegen the scanner.
Here's what they look like with this patch (note this is on the before data files,
so only string cols are dictionary encoded).
Before query times:
Insert Time: 8.5 sec
select *: 2.3 sec
select avg(l_orderkey): .33 sec
After query times:
Insert Time: 9.5 sec <-- Longer due to doing dictionary encoding
select *: 2.4 sec <-- kind of noisy, possibly a slight slow down
select avg(l_orderkey): .33 sec
Change-Id: I213fdca1bb972cc200dc0cd9fb14b77a8d36d9e6
Reviewed-on: http://gerrit.ent.cloudera.com:8080/238
Tested-by: jenkins <kitchen-build@cloudera.com>
Reviewed-by: Skye Wanderman-Milne <skye@cloudera.com>
This is the first set of changes required to start getting our functional test
infrastructure moved from JUnit to Python. After investigating a number of
option, I decided to go with a python test executor named py.test
(http://pytest.org/). It is very flexible, open source (MIT licensed), and will
enable us to do some cool things like parallel test execution.
As part of this change, we now use our "test vectors" for query test execution.
This will be very nice because it means if load the "core" dataset you know you
will be able to run the "core" query tests (specified by --exploration_strategy
when running the tests).
You will see that now each combination of table format + query exec options is
treated like an individual test case. this will make it much easier to debug
exactly where something failed.
These new tests can be run using the script at tests/run-tests.sh
This change updates the run-benchmark script to enable it to target one or more
workloads. Now benchmarks can be run like:
./run-benchmark --workloads=hive-benchmark,tpch
We lookup the workload in the workloads directory, then read the associated
query .test files and start executing them.
To ensure the queries are not duplicated between benchmark and query tests, I
moved all existing queries (under fe/src/test/resources/* to the workloads
directory. You do NOT need to look through all the .test files, I've just moved
them. The one new file is the 'hive-benchmark.test' which contains the hive
benchmark queries.
Also added support for generating schema for different scale factors as well as
executing against these scale factors. For example, let's say we have a dataset
with a scale factor called "SF1". We would first generate the schema using:
./generate_schema_statements --workload=<workload> --scale_factor="SF3"
This will create tables with a unique names from the other scale factors.
Run the generated .sql file to load the data. Alternatively, the data can loaded
by running a new python script:
./bin/load-data.py -w <workload1>,<workload2> -e <exploration strategy> -s [scale factor]
For example: load-data.sh -w tpch -e core -s SF3
Then run against this:
./run-benchmark --workloads=<workload> --scale_factor=SF3
This changeset also includes a few other minor tweaks to some of the test
scripts.
Change-Id: Ife8a8d91567d75c9612be37bec96c1e7780f50d6
