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Diffstat (limited to 'doc/development/query_performance.md')
| -rw-r--r-- | doc/development/query_performance.md | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/doc/development/query_performance.md b/doc/development/query_performance.md index bc1f753c012..4fe27d42c38 100644 --- a/doc/development/query_performance.md +++ b/doc/development/query_performance.md @@ -1,5 +1,5 @@ --- -stage: Enablement +stage: Data Stores group: Database info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments --- @@ -11,7 +11,7 @@ This document describes various guidelines to follow when optimizing SQL queries When you are optimizing your SQL queries, there are two dimensions to pay attention to: 1. The query execution time. This is paramount as it reflects how the user experiences GitLab. -1. The query plan. Optimizing the query plan is important in allowing queries to independently scale over time. Realizing that an index will keep a query performing well as the table grows before the query degrades is an example of why we analyze these plans. +1. The query plan. Optimizing the query plan is important in allowing queries to independently scale over time. Realizing that an index keeps a query performing well as the table grows before the query degrades is an example of why we analyze these plans. ## Timing guidelines for queries @@ -39,9 +39,9 @@ cache, or what PostgreSQL calls shared buffers. This is the "warm cache" query. When analyzing an [`EXPLAIN` plan](understanding_explain_plans.md), you can see the difference not only in the timing, but by looking at the output for `Buffers` by running your explain with `EXPLAIN(analyze, buffers)`. [Database Lab](understanding_explain_plans.md#database-lab-engine) -will automatically include these options. +automatically includes these options. -If you are making a warm cache query, you will only see the `shared hits`. +If you are making a warm cache query, you see only the `shared hits`. For example in #database-lab: @@ -57,7 +57,7 @@ Or in the explain plan from `psql`: Buffers: shared hit=7323 ``` -If the cache is cold, you will also see `reads`. +If the cache is cold, you also see `reads`. In #database-lab: |