<p>MySQL throws error 1805 when the stored column count for a table differs from the actual definition, indicating table corruption.</p>
<p>MySQL Error 1805 ER_COL_COUNT_DOESNT_MATCH_CORRUPTED_V2 happens when MySQL detects that the number of columns recorded in the .frm file differs from the real table structure. Running CHECK TABLE and then REPAIR TABLE or recreating the table usually resolves the corruption.</p>
Column count of %s.%s is wrong. Expected %d, found %d.
Error 1805 signals that MySQL expected one column count but found another when opening the table definition file. The mismatch flags internal corruption.
The server refuses to access the table to protect data integrity, so queries that read or write to the table fail immediately.
The message can surface during SELECT, INSERT, UPDATE, or ALTER operations that touch the corrupted table. It also shows up after server restarts when MySQL’s metadata cache refreshes.
Databases running on unreliable disks or after abrupt crashes are most prone, but version upgrades with incompatible storage formats can trigger the issue as well.
Ignoring corruption risks permanent data loss if the damage spreads. Repairing early restores application uptime and prevents cascading failures during backups or replication.
If mysqld stops unexpectedly while adding or dropping columns, the .frm file may be only partially updated.
Bad sectors, disk full events, or sudden power loss can corrupt InnoDB’s data dictionary or MyISAM’s .frm files.
Older MySQL versions contain known defects that write incorrect metadata after ALTER TABLE operations.
Moving .frm or .ibd files between servers without matching engine settings causes column count mismatches.
Occurs when a MyISAM table is marked as crashed. REPAIR TABLE usually resolves it.
Indicates problems in the .MYI index file. Similar repair steps apply.
Arises during ALTER TABLE when duplicate index names exist, but no corruption.
Shown when a table uses an older row format after a server upgrade.
Usually not. The data pages are often intact; only the metadata header is corrupt. Timely repair recovers the table.
No. InnoDB tables require ALTER TABLE ... FORCE or a dump and reload. REPAIR TABLE affects MyISAM only.
The server stays up, but any query touching the table fails. Other tables remain accessible.
Galaxy’s editor surfaces CHECK TABLE errors instantly and lets teams share repair scripts, reducing downtime.
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