MDEV-38936 Proactive handling of InnoDB tablespace full condition

[FarihaIS]

Description

InnoDB write failures occur when tablespace files exceed filesystem size limits (e.g. 16TB on ext4, 2TB on ext3 - varies by filesystem). Current behavior logs errors but continues accepting transactions, causing repeated failures, user disruption, and potential data integrity issues.

Add proactive monitoring by emitting warnings when InnoDB tablespaces exceed 90% of a configurable threshold. Warnings appear at each percentage point (90%, 91%, 92%, etc.) to prevent log flooding.

Key features:

• Two new system variables: innodb_tablespace_size_warning_threshold (default 16TB) and innodb_tablespace_size_warning_enabled (andon cord)
• Per-tablespace tracking with automatic reset on TRUNCATE/DROP
• Zero overhead when disabled
• Progressive warnings capped at 100%

Implementation hooks into fsp_try_extend_data_file() for O(1) size checking during tablespace extension. Adds 9 bytes per tablespace (m_last_size_warning_pct, m_last_warning_threshold) to fil_space_t structure.

Release Notes

Added proactive InnoDB tablespace size monitoring to prevent filesystem size limit failures. Two new system variables allow configuring warning thresholds and enable/disable functionality.

How can this PR be tested?

Execute the innodb.tablespace_size_warning test in mysql-test-run. This commit adds a test in the innodb suite.

The expected behavior is to emit warnings in the error log when a tablespace grows beyond 90% of the configured threshold:

[Warning] InnoDB: Tablespace 'test/t1' size 9437184 bytes (90%) exceeds warning threshold of 10485760 bytes
[Warning] InnoDB: Tablespace 'test/t1' size 9543680 bytes (91%) exceeds warning threshold of 10485760 bytes

Basing the PR against the correct MariaDB version

• This is a new feature, and the PR is based against the main branch.

Copyright

All new code of the whole pull request, including one or several files that are either new files or modified ones, are contributed under the BSD-new license. I am contributing on behalf of my employer Amazon Web Services, Inc.

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[mikegriffin]

Feature request, allow additional use cases (example, tablespace becomes larger than expected):

• Make a configurable warning percent (tablespace_size_warning_pct) so warnings can start earlier without changing the byte threshold
• Replace hard-coded 90 with a named constant (high_resolution_pct)
• No change above high_resolution_pct: print on every 1% increase
• Between tablespace_size_warning_pct and high_resolution_pct: print at most twice per 10% (example, 70%, 77%, 81%, 89%, 90%, 91%, 92%)