Commit Graph

8 Commits

Author SHA1 Message Date
Nikita Taranov
b93f483a0e fix build 2024-03-22 20:07:12 +00:00
Maksim Kita
2a327107b6 Updated implementation 2024-01-25 14:31:49 +03:00
Robert Schulze
60f9f6855d
feat: implement catboost in library-bridge
This commit moves the catboost model evaluation out of the server
process into the library-bridge binary. This serves two goals: On the
one hand, crashes / memory corruptions of the catboost library no longer
affect the server. On the other hand, we can forbid loading dynamic
libraries in the server (catboost was the last consumer of this
functionality), thus improving security.

SQL syntax:

  SELECT
    catboostEvaluate('/path/to/model.bin', FEAT_1, ..., FEAT_N) > 0 AS prediction,
    ACTION AS target
  FROM amazon_train
  LIMIT 10

Required configuration:

  <catboost_lib_path>/path/to/libcatboostmodel.so</catboost_lib_path>

*** Implementation Details ***

The internal protocol between the server and the library-bridge is
simple:

- HTTP GET on path "/extdict_ping":
  A ping, used during the handshake to check if the library-bridge runs.

- HTTP POST on path "extdict_request"
  (1) Send a "catboost_GetTreeCount" request from the server to the
      bridge, containing a library path (e.g /home/user/libcatboost.so) and
      a model path (e.g. /home/user/model.bin). Rirst, this unloads the
      catboost library handler associated to the model path (if it was
      loaded), then loads the catboost library handler associated to the
      model path, then executes GetTreeCount() on the library handler and
      finally sends the result back to the server. Step (1) is called once
      by the server from FunctionCatBoostEvaluate::getReturnTypeImpl(). The
      library path handler is unloaded in the beginning because it contains
      state which may no longer be valid if the user runs
      catboost("/path/to/model.bin", ...) more than once and if "model.bin"
      was updated in between.
  (2) Send "catboost_Evaluate" from the server to the bridge, containing
      the model path and the features to run the interference on. Step (2)
      is called multiple times (once per chunk) by the server from function
      FunctionCatBoostEvaluate::executeImpl(). The library handler for the
      given model path is expected to be already loaded by Step (1).

Fixes #27870
2022-09-08 09:01:32 +00:00
Robert Schulze
912663b719
Revert "Move CatBoost evaluation into clickhouse-library-bridge" 2022-08-31 20:54:43 +02:00
Robert Schulze
6b2b3c1eb3
feat: implement catboost in library-bridge
This commit moves the catboost model evaluation out of the server
process into the library-bridge binary. This serves two goals: On the
one hand, crashes / memory corruptions of the catboost library no longer
affect the server. On the other hand, we can forbid loading dynamic
libraries in the server (catboost was the last consumer of this
functionality), thus improving security.

SQL syntax:

  SELECT
    catboostEvaluate('/path/to/model.bin', FEAT_1, ..., FEAT_N) > 0 AS prediction,
    ACTION AS target
  FROM amazon_train
  LIMIT 10

Required configuration:

  <catboost_lib_path>/path/to/libcatboostmodel.so</catboost_lib_path>

*** Implementation Details ***

The internal protocol between the server and the library-bridge is
simple:

- HTTP GET on path "/extdict_ping":
  A ping, used during the handshake to check if the library-bridge runs.

- HTTP POST on path "extdict_request"
  (1) Send a "catboost_GetTreeCount" request from the server to the
      bridge, containing a library path (e.g /home/user/libcatboost.so) and
      a model path (e.g. /home/user/model.bin). Rirst, this unloads the
      catboost library handler associated to the model path (if it was
      loaded), then loads the catboost library handler associated to the
      model path, then executes GetTreeCount() on the library handler and
      finally sends the result back to the server. Step (1) is called once
      by the server from FunctionCatBoostEvaluate::getReturnTypeImpl(). The
      library path handler is unloaded in the beginning because it contains
      state which may no longer be valid if the user runs
      catboost("/path/to/model.bin", ...) more than once and if "model.bin"
      was updated in between.
  (2) Send "catboost_Evaluate" from the server to the bridge, containing
      the model path and the features to run the interference on. Step (2)
      is called multiple times (once per chunk) by the server from function
      FunctionCatBoostEvaluate::executeImpl(). The library handler for the
      given model path is expected to be already loaded by Step (1).

Fixes #27870
2022-08-29 20:26:45 +00:00
Robert Schulze
9952ab1099
Prefix class names "LibraryBridge*Handler" with "ExternalDictionary"
- necessary to disambiguate the names from "CatBoost"-"LibraryBridgeHandler"
  which will be added in a next step
2022-08-08 17:16:46 +00:00
Robert Schulze
20bb8a248e
Prepare server-side BridgeHelper for catboost integration
Wall of text, sorry, but I also had to document some stuff for myself:

There are three ways to communicate data using HTTP:
- the HTTP verb: for our purposes, PUT and GET,
- the HTTP path: '/ping', '/request' etc.,
- the HTTP URL parameter(s), e.g. 'method=libNew&dictionary_id=1234'

The bridge will use different handlers for communication with the
external dictionary library and for communication with the catboost
library. Handlers are created based on a combination of the HTTP verb
and the HTTP method. More specifically, there will be combinations
- GET + '/extdict_ping'
- PUT + '/extdict_request'
- GET + '/catboost_ping'
- PUT + '/catboost_request'.
For each combination, the bridge expects a certain set of URL
parameters, e.g. for the first combination parameter "dictionary_id" is
expected.

Starting with this commit, the library-bridge creates handlers based on
the first two combinations (the latter two combinations will be added
later). This makes the handler creation mechanism consistent with it's
counterpart in xdbc-bridge.

For that, it was necessary to make both IBridgeHelper methods
"getMainURI()" and "getPingURI()" pure virtual so that derived classes
(LibraryBridgeHelper and XDBCBridgeHelper) must provide custom URLs with
custom paths.

Side note 1: Previously, LibraryBridgeHelper sent HTTP URL parameter
"method=ping" during handshake (PING) but the library-bridge ignored
that parameter. We now omit this parameter, i.e.
LibraryBridgeHelper::PING was removed. Again, this makes things
consistent with xdbc-bridge.

Side note 2: xdbc-bridge is unchanged in this commit. Therefore,
XDBCBridgeHelper now uses the HTTP paths previously in the base class.
For funny reason, XDBCBridgeHelper did not use
IBridgeHelper::getMainURI() - it generates the URLs by itself. I kept it
that way for now but provided an implementation of getMainURI() anyways.
2022-08-04 19:29:51 +00:00
Robert Schulze
ea73b98fb9
Prepare library-bridge for catboost integration
- Rename generic file and identifier names in library-bridge to
  something more dictionary-specific. This is needed because later on,
  catboost will be integrated into library-bridge.

- Also: Some smaller fixes like typos and un-inlining non-performance
  critical code.

- The logic remains unchanged in this commit.
2022-08-04 19:26:51 +00:00