pg_dump may fail with an OOM error due to plugindata table size
Platform Notice: Data Center Only - This article only applies to Atlassian products on the Data Center platform.
Note that this KB was created for the Data Center version of the product. Data Center KBs for non-Data-Center-specific features may also work for Server versions of the product, however they have not been tested. Support for Server* products ended on February 15th 2024. If you are running a Server product, you can visit the Atlassian Server end of support announcement to review your migration options.
*Except Fisheye and Crucible
Summary
Problem
The plugindata table of Confluence keeps the user-installed plugin .jar files. The table saves the entire .jar file (size) on the data column, during Confluence startup, it reads from this table and populates the plugins-cache folder of Confluence.
On this table, when using pSQL, the data type used by the column data is bytea (binary data). This type has a limitation in pSQL when being read which may cause an OOM:
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select data from plugindata;
ERROR: out of memory
DETAIL: Failed on request of size 268435456.
Backup error:
pg_dump: Dumping the contents of table "plugindata" failed: PQgetResult() failed.
pg_dump: Error message from server: ERROR: out of memory
DETAIL: Failed on request of size 159380181.
pg_dump: The command was: COPY public.plugindata (plugindataid, pluginkey, filename, lastmoddate, data) TO stdout;Diagnosis
Environment
PostgreSQL 9.6.x
Cause
The root cause for the memory issue is that you are selecting the output of a bytea column in text mode(i.e. either for SELECT or pg_dump), it requires more memory than the size of the underlying datum.
The limit for such memory allocations in PostgreSQL is 1GB.
Solution
Workaround
If you hit this problem when running a pg_dump, use lo_import and lo_export to create the dump successfully.
Clearing Confluence Plugin Cache folders can help temporarily
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