If your table is prone to frequent updates or insertions, then we recommend
periodically reindexing the existing ScaNN index
in order to improve the recall accuracy for your index. You can monitor
index metrics to view changes in vector distributions or vector mutations since
the index was built, and then reindex accordingly.
You can manually rebuild your index if you want to
rebuild it with the configurations you specified when it was created.
To manually rebuild your index, run the following command:
REINDEXINDEXCONCURRENTLYINDEX_NAME;
Replace INDEX_NAME with the name of the index you want to
rebuild—for example, my-scann-index. The index names are shared
across your database. Ensure that each index name is unique to each
table in your database.
For more information about reindexing in PostgreSQL, see
REINDEX.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-25 UTC."],[],[],null,["# Maintain vector indexes\n\nSelect a documentation version: 15.12.0keyboard_arrow_down\n\n- [Current (16.8.0)](/alloydb/omni/current/docs/ai/maintain-vector-indexes)\n- [16.8.0](/alloydb/omni/16.8.0/docs/ai/maintain-vector-indexes)\n- [16.3.0](/alloydb/omni/16.3.0/docs/ai/maintain-vector-indexes)\n- [15.12.0](/alloydb/omni/15.12.0/docs/ai/maintain-vector-indexes)\n- [15.7.1](/alloydb/omni/15.7.1/docs/ai/maintain-vector-indexes)\n- [15.7.0](/alloydb/omni/15.7.0/docs/ai/maintain-vector-indexes)\n\n\u003cbr /\u003e\n\nThis document explains different options that you can use to maintain vector indexes. You might want to maintain indexes to ensure that your indexes adapt to the changes in data that might impact accuracy of your search results. As your dataset grows, use the strategies in the following sections to avoid degradation in query performance.\n\n\u003cbr /\u003e\n\nView vector index metrics\n-------------------------\n\nIf your table is prone to frequent updates or insertions, then we recommend\nperiodically [reindexing the existing ScaNN index](#manually-rebuild-index)\nin order to improve the recall accuracy for your index. You can monitor\nindex metrics to view changes in vector distributions or vector mutations since\nthe index was built, and then reindex accordingly.\n\nFor more information about metrics, see [View Vector index metrics](/alloydb/omni/15.12.0/docs/reference/vector-index-metrics).\n\nManually rebuild your index\n---------------------------\n\nYou can manually rebuild your index if you want to\nrebuild it with the configurations you specified when it was created.\n\nTo manually rebuild your index, run the following command: \n\n REINDEX INDEX CONCURRENTLY \u003cvar translate=\"no\"\u003e\u003cspan class=\"devsite-syntax-n\"\u003eINDEX_NAME\u003c/span\u003e\u003c/var\u003e;\n\nReplace \u003cvar translate=\"no\"\u003eINDEX_NAME\u003c/var\u003e with the name of the index you want to\nrebuild---for example, `my-scann-index`. The index names are shared\nacross your database. Ensure that each index name is unique to each\ntable in your database.\n\nFor more information about reindexing in PostgreSQL, see\n[REINDEX](https://www.postgresql.org/docs/15/sql-reindex.html).\n\nWhat's next\n-----------\n\n- [Vector index metrics](/alloydb/omni/15.12.0/docs/reference/vector-index-metrics)\n- [Optimize vector query performance for ScaNN](/alloydb/omni/15.12.0/docs/ai/scann-vector-query-perf-overview)"]]