block / mysql / 33118200785

83%

master: 83%

Build Type

Pull #2

github

Committed by morgo

Commit Message

conn: expose the OK/EOF packet warning count

MySQL reports how many warnings a statement raised in the packet that
terminates its response, but the driver dropped the field on the floor: a
literal `// warning count [2 bytes]` comment in handleOkPacket with no
parse behind it, and three copies of the resultset terminator reader that
skipped straight past it to the status flags.

Without the count, a caller that wants to surface warnings has only bad
options. The diagnostics themselves live in per-connection state that
only SHOW WARNINGS can read, so reading them costs a round trip; with no
count to gate on, that round trip has to be spent after every statement,
warnings or not. The count is what makes it affordable — and it is also
what a proxy needs to put in its own OK packet, since clients such as
Connector/J only ask for warnings when the count they were given is
non-zero.

Record it on the connection alongside the status flags, clear it in
clearResult() so one statement's count cannot be read as the next one's,
and expose it as (*mysqlConn).Warnings() for callers reaching the
connection through (*sql.Conn).Raw.

The three inlined resultset terminator readers collapse into one
readResultsetTerminator method. They were already identical; the warning
count made keeping them identical harder, because an EOF packet orders
warnings before status and an 0xFE-headered OK packet orders them after,
so each copy would have had to get that backwards independently.

Pull Request Pull Request #2: conn: expose the OK/EOF packet warning count

Coverage Stats

29 of 29 new or added lines in 3 files covered. (100.0%)

189 existing lines in 2 files now uncovered.

3450 of 4170 relevant lines covered (82.73%)

2572360.81 hits per line