Commit Graph

5 Commits

Author SHA1 Message Date
Robert Schulze
fd97058e45
fix: incorporate review comments 2022-09-14 15:21:24 +00:00
Robert Schulze
fac1be9700
chore: restore SYSTEM RELOAD MODEL(S) and moniting view SYSTEM.MODELS
- This commit restores statements "SYSTEM RELOAD MODEL(S)" which provide
  a mechanism to update a model explicitly. It also saves potentially
  unnecessary reloads of a model from disk after it's initial load.

  To keep the complexity low, the semantics of "SYSTEM RELOAD MODEL(S)
  was changed from eager to lazy. This means that both statements
  previously immedately reloaded the specified/all models, whereas now
  the statements only trigger an unload and the first call to
  catboostEvaluate() does the actual load.

- Monitoring view SYSTEM.MODELS is also restored but with some obsolete
  fields removed. The view was not documented in the past and for now it
  remains undocumented. The commit is thus not considered a breach of
  ClickHouse's public interface.
2022-09-12 19:33:02 +00:00
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