Question

What would happen if I was to insert say 1000 rows (taking 20 seconds, but one query). After 2 seconds someone else tried to insert a row at the same location e.g.

20secondquery
1|yellow
2|blue
3|green
4|violet

2secondquery
4|blue

Would their row be inserted or would it queue until my insert was finished?
(MyISAM)

Answer 1

Depends on what sort of transactions and/or locking you’re using.

If someone issues a single big INSERT statement, that will complete atomically as a single operation. If they are spamming a whole bunch of INSERTS, then the secondquery will fall in between those.

You need to look into Table Locking to control this sort of thing.

LOCK TABLES widgets WRITE;
INSERT INTO widgets (name) VALUES ('Widget A');
INSERT INTO widgets (name) VALUES ('Widget B');
INSERT INTO widgets (name) VALUES ('Widget C');
INSERT INTO widgets (name) VALUES ('Widget D');
INSERT INTO widgets (name) VALUES ('Widget E');
UNLOCK TABLES;

For the time between the LOCK TABLES and UNLOCK TABLES nothing else will be able to read or write to the table.