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Diffstat (limited to 'doc/integration/elasticsearch.md')
| -rw-r--r-- | doc/integration/elasticsearch.md | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/doc/integration/elasticsearch.md b/doc/integration/elasticsearch.md index 3ef54ca6dd3..2d53e021f81 100644 --- a/doc/integration/elasticsearch.md +++ b/doc/integration/elasticsearch.md @@ -466,13 +466,13 @@ When performing a search, the GitLab index will use the following scopes: ### Deleted documents -Whenever a change or deletion is made to an indexed GitLab object (a merge request description is changed, a file is deleted from the master branch in a repository, a project is deleted, etc), a document in the index is deleted. However, since these are "soft" deletes, the overall number of "deleted documents", and therefore wasted space, increases. Elasticsearch does intelligent merging of segments in order to remove these deleted documents. However, depending on the amount and type of activity in your GitLab installation, it's possible to see as much as 50% wasted space in the index. +Whenever a change or deletion is made to an indexed GitLab object (a merge request description is changed, a file is deleted from the master branch in a repository, a project is deleted, etc), a document in the index is deleted. However, since these are "soft" deletes, the overall number of "deleted documents", and therefore wasted space, increases. Elasticsearch does intelligent merging of segments in order to remove these deleted documents. However, depending on the amount and type of activity in your GitLab installation, it's possible to see as much as 50% wasted space in the index. In general, we recommend simply letting Elasticsearch merge and reclaim space automatically, with the default settings. From [Lucene's Handling of Deleted Documents](https://www.elastic.co/blog/lucenes-handling-of-deleted-documents "Lucene's Handling of Deleted Documents"), _"Overall, besides perhaps decreasing the maximum segment size, it is best to leave Lucene's defaults as-is and not fret too much about when deletes are reclaimed."_ However, some larger installations may wish to tune the merge policy settings: -- Consider reducing the `index.merge.policy.max_merged_segment` size from the default 5 GB to maybe 2 GB or 3 GB. Merging only happens when a segment has at least 50% deletions. Smaller segment sizes will allow merging to happen more frequently. +- Consider reducing the `index.merge.policy.max_merged_segment` size from the default 5 GB to maybe 2 GB or 3 GB. Merging only happens when a segment has at least 50% deletions. Smaller segment sizes will allow merging to happen more frequently. ```shell curl --request PUT localhost:9200/gitlab-production/_settings ---header 'Content-Type: application/json' --data '{ @@ -482,7 +482,7 @@ However, some larger installations may wish to tune the merge policy settings: }' ``` -- You can also adjust `index.merge.policy.reclaim_deletes_weight`, which controls how aggressively deletions are targeted. But this can lead to costly merge decisions, so we recommend not changing this unless you understand the tradeoffs. +- You can also adjust `index.merge.policy.reclaim_deletes_weight`, which controls how aggressively deletions are targeted. But this can lead to costly merge decisions, so we recommend not changing this unless you understand the tradeoffs. ```shell curl --request PUT localhost:9200/gitlab-production/_settings ---header 'Content-Type: application/json' --data '{ @@ -492,7 +492,7 @@ However, some larger installations may wish to tune the merge policy settings: }' ``` -- Do not do a [force merge](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-forcemerge.html "Force Merge") to remove deleted documents. A warning in the [documentation](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-forcemerge.html "Force Merge") states that this can lead to very large segments that may never get reclaimed, and can also cause significant performance or availability issues. +- Do not do a [force merge](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-forcemerge.html "Force Merge") to remove deleted documents. A warning in the [documentation](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-forcemerge.html "Force Merge") states that this can lead to very large segments that may never get reclaimed, and can also cause significant performance or availability issues. ## Troubleshooting |