MySQL AIops

[READ] InnoDB wait-for edges (blocked session -> blocking session). Reads performance_schema.data_lock_waits on MySQL 8.x, or information_schema.innodb_lock_waits on MariaDB (flavor-branched). Args: target: Target name from config; omit for the default.

[READ] Active statements running at least ``min_seconds``, oldest first. Args: min_seconds: Minimum age in seconds (default 60). target: Target name from config; omit for the default.

[WRITE][risk=medium] OPTIMIZE TABLE (rebuild, reclaim data_free). Records prior stats. No undo (a rebuild has no inverse); the prior size/fragmentation stats are captured for the audit trail. InnoDB maps this to ALTER TABLE ... FORCE (online DDL, brief locks) — schedule off-peak for hot tables. Pass dry_run=True to preview. Args: table: Table name (optionally schema-qualified, e.g. shop.orders). dry_run: If True, preview without running. target: Target name from config; omit for the default.

[READ] One-shot server health snapshot. Version + flavor (mysql/mariadb) + uptime, connection headroom vs max_connections, sessions by command, the longest-running query, the most fragmented table, and the replica role — each section captured defensively so one failing probe does not sink the rest. Args: target: Target name from config; omit for the default.

[READ] Indexes whose columns are a leading prefix of another index (dupes). Args: target: Target name from config; omit for the default.

[READ] Replica thread state and lag (SHOW REPLICA/SLAVE STATUS, flavor-branched). Empty on a primary/standalone server. MySQL 8.x uses SHOW REPLICA STATUS; MariaDB uses SHOW SLAVE STATUS — the result is normalised either way. Args: target: Target name from config; omit for the default.

[READ] Map replica thread state / lag / error fields to cause + action. Pass 'status' (as from replica_status) for pure/offline analysis, or omit to pull the live replica status (flavor-branched). Args: status: Injected replica status record; if omitted, pulled live. target: Target name from config; omit for the default.

[WRITE][risk=medium] Reset statement-digest accumulators (irreversible). Truncates performance_schema.events_statements_summary_by_digest; the counters cannot be restored, so no undo is recorded. Pass dry_run=True to preview. Args: dry_run: If True, preview without resetting. target: Target name from config; omit for the default.

[READ] Server version, flavor (mysql/mariadb), uptime and read-only state. Args: target: Target name from config; omit for the default.

[WRITE][risk=medium] SET GLOBAL a server variable. Reversible: captures prior value. Runtime-only: the change does not survive a restart (persist it in my.cnf — or SET PERSIST on MySQL 8 — yourself); reported but NOT performed automatically. The prior value (from SHOW GLOBAL VARIABLES) is captured so the harness records an undo that sets it back. Pass dry_run=True to preview. Refuses the globals that would lock this tool out of the server (init_connect, max_connections, max_user_connections, read_only, super_read_only, skip_networking, require_secure_transport, and wait_timeout/interactive_t…

[READ] Global status counters (SHOW GLOBAL STATUS). Args: pattern: Optional substring to filter counter names (e.g. 'Threads', 'Innodb_buffer_pool'). target: Target name from config; omit for the default.

[READ] Global variables (SHOW GLOBAL VARIABLES). Args: pattern: Optional substring to filter variable names (e.g. 'innodb_buffer', 'max_connections'). target: Target name from config; omit for the default.

[READ] RCA for the worst statement digest, with cause + action. Picks the digest with the greatest total time and maps its numbers (no-index share, lock-time share, examined/sent ratio, tmp-disk spill, calls) — plus an optional EXPLAIN plan — to cited causes and concrete actions. Pass 'statements' for pure/offline analysis, or omit to pull the top digests live from performance_schema. Args: statements: Injected digest rows (as from top_queries); if omitted, the worst statements are pulled live. explain_sql: Optional SQL to EXPLAIN so plan access types feed the RCA. limit:…

[READ] data_free per table (space OPTIMIZE TABLE could reclaim), worst first. Args: limit: Number of tables to inspect (default 50). target: Target name from config; omit for the default. Returns an envelope: {"tables": [...], "returned": N, "limit": L, "truncated": bool}. When "truncated" is true there is more beyond what was returned — re-run with a higher limit rather than treating this as the complete picture.

[READ] Largest tables by data + index size. Args: limit: Number of tables to return, largest first (default 20). target: Target name from config; omit for the default. Returns an envelope: {"tables": [...], "returned": N, "limit": L, "truncated": bool}. When "truncated" is true there is more beyond what was returned — re-run with a higher limit rather than treating this as the complete picture.

[READ] Per-table engine, row format, row estimate and last update time. Flags non-InnoDB tables (no row-level locking / crash recovery). Args: limit: Number of tables to inspect (default 50). target: Target name from config; omit for the default. Returns an envelope: {"tables": [...], "returned": N, "limit": L, "truncated": bool}. When "truncated" is true there is more beyond what was returned — re-run with a higher limit rather than treating this as the complete picture.

[READ] Top statement digests from performance_schema by a whitelisted metric. Args: order_by: One of total_time, mean_time, calls, rows_examined, lock_time, no_index. limit: Number of statements to return (1..200, default 20). target: Target name from config; omit for the default. Returns an envelope: {"statements": [...], "returned": N, "limit": L, "truncated": bool}. When "truncated" is true there is more beyond what was returned — re-run with a higher limit rather than treating this as the complete picture.

[WRITE][risk=medium] Apply a recorded undo by dispatching its inverse tool. The inverse runs through its own governed tool, so its own risk tier and audit row are recorded there. Pass dry_run=True to preview the inverse call without executing it. A token can only be applied once. Args: undo_id: The undoId from undo_list (or an ``_undo_id`` in a write result). dry_run: If True, preview the inverse tool + params without running it. target: Passed through to the inverse tool when it accepts a target.

[READ] List recorded, not-yet-applied undo tokens (most recent first). Each entry names the original tool, the inverse tool that ``undo_apply`` would run, and a human note. Use the ``undoId`` with ``undo_apply``. Returns {"undos": [...], "returned": N, "limit": L, "truncated": bool}. ``truncated`` is *measured* (one extra row is fetched), not guessed from a length coincidence: when it is true there are MORE tokens than shown, so re-run with a higher ``limit`` rather than reporting the list as complete. Each entry carries ``effectVerified``. False means the original write lost its response, …

[READ] Secondary indexes with zero I/O events since restart (drop candidates). From performance_schema.table_io_waits_summary_by_index_usage — counters reset on server restart, so confirm over a full business cycle. Args: target: Target name from config; omit for the default.