Mercurial > hg > orthanc-book
comparison Sphinx/source/faq/scalability.rst @ 438:5d6d593bceb6
scalability section
| author | Alain Mazy <alain@mazy.be> |
|---|---|
| date | Tue, 26 May 2020 08:21:29 +0200 |
| parents | c95817c254fe |
| children | 86bf70a1f570 |
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| 436:0942c745d2b5 | 438:5d6d593bceb6 |
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| 160 options available as environment variables that could also reduce | 160 options available as environment variables that could also reduce |
| 161 memory consumption (for instance, ``MALLOC_MMAP_THRESHOLD_`` would | 161 memory consumption (for instance, ``MALLOC_MMAP_THRESHOLD_`` would |
| 162 bypass arenas for large memory blocks such as DICOM files). Check out | 162 bypass arenas for large memory blocks such as DICOM files). Check out |
| 163 the `manpage <http://man7.org/linux/man-pages/man3/mallopt.3.html>`__ | 163 the `manpage <http://man7.org/linux/man-pages/man3/mallopt.3.html>`__ |
| 164 of ``mallopt()`` for more information. | 164 of ``mallopt()`` for more information. |
| 165 | |
| 166 | |
| 167 .. _scalability-limitations: | |
| 168 | |
| 169 Known limitations | |
| 170 ----------------- | |
| 171 | |
| 172 Exclusive access to the DB | |
| 173 ^^^^^^^^^^^^^^^^^^^^^^^^^^ | |
| 174 | |
| 175 As of Orthanc 1.7.0, the internal code accessing the DB is still affected | |
| 176 by limitations induced by the SQLite engine that was the only one originally | |
| 177 available at the beginning of the project: inside a single Orthanc process, | |
| 178 there are no concurrent access to the DB. | |
| 179 | |
| 180 One solution to avoid this limitation is to have multiple Orthanc accessing | |
| 181 the same DB (works only for MySQL and PostgreSQL) as presented in this `sample | |
| 182 <https://bitbucket.org/osimis/orthanc-setup-samples/src/master/docker/multiple-orthancs-on-same-db/>`__. | |
| 183 | |
| 184 Also note that the core of Orthanc does not currently support the replay | |
| 185 of database transactions, which is necessary to deal with conflicts | |
| 186 between several instances of Orthanc that would simultaneously write | |
| 187 to the database. As a consequence, as of Orthanc 1.7.0, when connecting multiple | |
| 188 Orthanc to a single database by setting ``Lock`` to ``false``, there | |
| 189 should only be one instance of Orthanc acting as a writer and all the | |
| 190 other instances of Orthanc acting as readers only. Be careful to set | |
| 191 the option ``SaveJobs`` to ``false`` in the configuration file of all | |
| 192 the instances of Orthanc acting as readers. | |
| 193 | |
| 194 A refactoring is needed to improve the core of Orthanc in that | |
| 195 respect, for which we are looking for funding from the | |
| 196 industry. Some issues reported in our bug tracker call for this | |
| 197 refactoring: `issue 83 | |
| 198 <https://bitbucket.org/sjodogne/orthanc/issues/83/>`__, `issue 121 | |
| 199 <https://bitbucket.org/sjodogne/orthanc/issues/121/>`__, `issue 151 | |
| 200 <https://bitbucket.org/sjodogne/orthanc/issues/151/>`__. | |
| 201 |