Oracle 23ai vector search needs vector_memory_size set plus a restart

Not specified by the original author.

TL;DR

Set vectormemorysize with SCOPE=SPFILE and restart the database for it to apply; the setting does nothing until the restart. On the 23ai Free edition with 2 GB of RAM, keep the allocation conservative so the vector pool does not starve core processes.

Steps

1. Set vectormemorysize with SCOPE=SPFILE and restart the database for it to apply; the setting does nothing until the restart. On the 23ai Free edition with 2 GB of RAM, keep the allocation conservative so the vector pool does not starve core processes. Verify the actual SGA composition in the startup log, not just the parameter value.

When to use

You are seeing this: On the 23ai Free edition with 2 GB of RAM, keep the allocation conservative so the vector pool does not starve core processes. Use this skill when you run into "Oracle 23ai vector search needs vectormemorysize set plus a restart".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Source: Oracle 23ai vector memory troubleshooting: documents the gotcha that AI Vector Search needs vectormemorysize set explicitly via ALTER SYSTEM with SCOPE=SPFILE, followed by a restart to take effect. The 23ai Free edition is limited to 2 GB of RAM, so over-allocating the vector pool starves other database processes; start conservative.

Verified resolution: Set vectormemorysize with SCOPE=SPFILE and restart the database for it to apply; the setting does nothing until the restart. On the 23ai Free edition with 2 GB of RAM, keep the allocation conservative so the vector pool does not starve core processes. Verify the actual SGA composition in the startup log, not just the parameter value.

Source URL: https://dev.to/smyekh/oracle-23ais-phantom-vector-memory-a-troubleshooting-guide-5a1j