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The Greenplum Query Optimizer
Copyright (c) 2015, Pivotal Software, Inc.
Licensed under the Apache License, Version 2.0
======================================================================
Welcome to GPORCA, the Greenplum Next Generation Query Optimizer!
To understand the objectives and architecture of GPORCA please refer to the following articles:
* [Orca: A Modular Query Optimizer Architecture for Big Data](https://content.pivotal.io/white-papers/orca-a-modular-query-optimizer-architecture-for-big-data).
* [Profiling Query Compilation Time with GPORCA](http://engineering.pivotal.io/post/orca-profiling/)
* [Improving Constraints In ORCA](http://engineering.pivotal.io/post/making-orca-smarter/)
Want to [Contribute](#contribute)?
GPORCA supports various build types: debug, release with debug info, release.
You'll need CMake 3.1 or higher to build the gporca_test and gpos_test
utilities to test GPORCA. Get it from cmake.org, or your operating system's
package manager.
# First Time Setup
## Build and install GPORCA
ORCA is built automatically with GPDB as long as `--disable-orca` is not used.
## Test GPORCA
To test GPORCA, first go into the `gporca` directory:
```
cmake -GNinja -H. -Bbuild
```
To run all GPORCA tests, simply use the `ctest` command from the build directory
after build finishes.
```
cd build
ctest
```
Much like `make`, `ctest` has a -j option that allows running multiple tests in
parallel to save time. Using it is recommended for faster testing.
```
ctest -j8
```
By default, `ctest` does not print the output of failed tests. To print the
output of failed tests, use the `--output-on-failure` flag like so (this is
useful for debugging failed tests):
```
ctest -j8 --output-on-failure
```
To run only the previously failed ctests, use the `--rerun-failed` flag.
```
ctest -j8 --rerun-failed --output-on-failure
```
To run a specific individual test, use the `gporca_test` executable directly.
```
./server/gporca_test -U CAggTest
```
To run a specific minidump, for example for `../data/dxl/minidump/TVFRandom.mdp`:
```
./server/gporca_test -d ../data/dxl/minidump/TVFRandom.mdp
```
Note that some tests use assertions that are only enabled for DEBUG builds, so
DEBUG-mode tests tend to be more rigorous.
## Adding tests
Most of the regression tests come in the form of a "minidump" file.
A minidump is an XML file that contains all the input needed to plan a query,
including information about all tables, datatypes, and functions used, as well
as statistics. It also contains the resulting plan.
A new minidump can be created by running a query on a live GPDB server:
1. Run these in a psql session:
```
set client_min_messages='log';
set optimizer=on;
set optimizer_enumerate_plans=on;
set optimizer_minidump=always;
set optimizer_enable_constant_expression_evaluation=off;
```
2. Run the query in the same psql session. It will create a minidump file
under the "minidumps" directory, in the master's data directory:
```
$ ls -l $MASTER_DATA_DIRECTORY/minidumps/
total 12
-rw------- 1 heikki heikki 10818 Jun 10 22:02 Minidump_20160610_220222_4_14.mdp
```
3. Run xmllint on the minidump to format it better, and copy it under the
data/dxl/minidump directory:
```
xmllint --format $MASTER_DATA_DIRECTORY/minidumps/Minidump_20160610_220222_4_14.mdp > data/dxl/minidump/MyTest.mdp
```
4. Add it to the test suite, in server/src/unittest/gpopt/minidump/CICGTest.cpp
```
--- a/server/src/unittest/gpopt/minidump/CICGTest.cpp
+++ b/server/src/unittest/gpopt/minidump/CICGTest.cpp
@@ -217,6 +217,7 @@ const CHAR *rgszFileNames[] =
"../data/dxl/minidump/EffectsOfJoinFilter.mdp",
"../data/dxl/minidump/Join-IDF.mdp",
"../data/dxl/minidump/CoerceToDomain.mdp",
+ "../data/dxl/minidump/Mytest.mdp",
"../data/dxl/minidump/LeftOuter2InnerUnionAllAntiSemiJoin.mdp",
#ifndef GPOS_DEBUG
// TODO: - Jul 14 2015; disabling it for debug build to reduce testing time
```
Alternatively, it could also be added to the proper test suite in `server/CMakeLists.txt` as follows:
```
--- a/server/CMakeLists.txt
+++ b/server/CMakeLists.txt
@@ -183,7 +183,8 @@ CPartTbl5Test:
PartTbl-IsNullPredicate PartTbl-IsNotNullPredicate PartTbl-IndexOnDefPartOnly
PartTbl-SubqueryOuterRef PartTbl-CSQ-PartKey PartTbl-CSQ-NonPartKey
PartTbl-LeftOuterHashJoin-DPE-IsNull PartTbl-LeftOuterNLJoin-DPE-IsNull
-PartTbl-List-DPE-Varchar-Predicates PartTbl-List-DPE-Int-Predicates;
+PartTbl-List-DPE-Varchar-Predicates PartTbl-List-DPE-Int-Predicates
+Mytest;
```
## Update tests
In some situations, a failing test does not necessarily imply that the fix is
wrong. Occasionally, existing tests need to be updated. There is now a script
that allows for users to quickly and easily update existing mdps. This script
takes in a logfile that it will use to update the mdps. This logfile can be
obtained from running ctest as shown below.
Existing minidumps can be updated by running the following:
1. Run `ctest -j8`.
2. If there are failing tests, run
```
ctest -j8 --rerun-failed --output-on-failure | tee /tmp/failures.out
```
3. The output file can then be used with the `fix_mdps.py` script.
```
gporca/scripts/fix_mdps.py --logFile /tmp/failures.out
```
Note: This will overwrite existing mdp files. This is best used after
committing existing changes, so you can more easily see the diff.
Alternatively, you can use `gporca/scripts/fix_mdps.py --dryRun` to not change
mdp files
4. Ensure that all changes are valid and as expected.
# Advanced Setup
## How to generate build files with different options
Here are a few build flavors (commands run from the ORCA checkout directory):
```
# debug build
cmake -GNinja -D CMAKE_BUILD_TYPE=Debug -H. -Bbuild.debug
```
```
# release build with debug info
cmake -GNinja -D CMAKE_BUILD_TYPE=RelWithDebInfo -H. -Bbuild.release
```
## Explicitly Specifying Xerces For Build
If you want to build with a custom version of Xerces, is recommended to use the
`--prefix` option to the Xerces-C configure script to install Xerces in a
location other than the default under `/usr/local/`, because you may have other
software that depends on the platform's version of Xerces-C. Installing in a
non-default prefix allows you to have GP-Xerces installed side-by-side with
unpatched Xerces without incompatibilities.
You can point cmake at your custom Xerces installation using the
`XERCES_INCLUDE_DIR` and `XERCES_LIBRARY` options like so:
However, to use the current build scripts in GPDB, Xerces will need to be
placed on the /usr path.
```
cmake -GNinja -D XERCES_INCLUDE_DIR=/opt/gp_xerces/include -D XERCES_LIBRARY=/opt/gp_xerces/lib/libxerces-c.so ..
```
Again, on Mac OS X, the library name will end with `.dylib` instead of `.so`.
## How to debug the build
Show all command lines while building (for debugging purpose)
```
ninja -v -C build
```
# How to Contribute
We accept contributions via [Github Pull requests](https://help.github.com/articles/using-pull-requests) only.
ORCA has a [style guide](StyleGuilde.md), try to follow the existing style in your contribution to be consistent.
[clang-format]: https://clang.llvm.org/docs/ClangFormat.html
A set of [clang-format]-based rules are enforced in CI. Your editor or IDE may automatically support it. When in doubt, check formatting locally before submitting your PR:
```
CLANG_FORMAT=clang-format src/tools/fmt chk
```
For more information, head over to the [formatting README](README.format.md).
We follow GPDB's comprehensive contribution policy. Please refer to it [here](https://github.com/greenplum-db/gpdb#contributing) for details.