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Fix prepared statement #734

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Merged
merged 5 commits into from
Jan 13, 2018
Merged

Fix prepared statement #734

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40352b0
Fix prepared statement
methane Jan 8, 2018
2954ddc
Change minimum size of LONG_DATA to 64byte
methane Jan 8, 2018
475ca26
Add test which reproduce issue 730
methane Jan 10, 2018
2661e90
TestPreparedManyCols test only numParams = 65535 case
methane Jan 10, 2018
d08f145
s/as possible//
methane Jan 13, 2018
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17 changes: 14 additions & 3 deletions driver_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1669,24 +1669,35 @@ func TestStmtMultiRows(t *testing.T) {
// Regression test for
// * more than 32 NULL parameters (issue 209)
// * more parameters than fit into the buffer (issue 201)
// * parameters * 64 > max_allowed_packet (issue 734)
func TestPreparedManyCols(t *testing.T) {
const numParams = defaultBufSize
numParams := 65535
runTests(t, dsn, func(dbt *DBTest) {
query := "SELECT ?" + strings.Repeat(",?", numParams-1)
stmt, err := dbt.db.Prepare(query)
if err != nil {
dbt.Fatal(err)
}
defer stmt.Close()

// create more parameters than fit into the buffer
// which will take nil-values
params := make([]interface{}, numParams)
rows, err := stmt.Query(params...)
if err != nil {
stmt.Close()
dbt.Fatal(err)
}
defer rows.Close()
rows.Close()

// Create 0byte string which we can't send via STMT_LONG_DATA.
for i := 0; i < numParams; i++ {
params[i] = ""
}
rows, err = stmt.Query(params...)
if err != nil {
dbt.Fatal(err)
}
rows.Close()
})
}

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10 changes: 8 additions & 2 deletions packets.go
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Expand Up @@ -912,6 +912,12 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
const minPktLen = 4 + 1 + 4 + 1 + 4
mc := stmt.mc

// Determine threshould dynamically to avoid packet size shortage as possible.
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s/threshould/threshold/

What do you mean by the "as possible"? When possible? As much as possible?
Are there still cases where the driver sends too short packets?

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What do you mean by the "as possible"? When possible? As much as possible?

Sorry, I'm not English speaker. I meant it's OK for most realistic use cases,
although there can be edge cases.

Are there still cases where the driver sends too short packets?

No, always send more than 64 bytes.
"shortage" meant there is chance which stmt_exec packet is bigger than
max_allowed_packet.
For example, user can set very small max_allowed_packet. In such case,
packet can be bigger than max_allowed_packet even when all data is sent
with STMT_LONG_DATA.

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I'm not good English writer. Could you rewrite this comment?

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just remove the "as possible"

longDataSize := mc.maxAllowedPacket / (stmt.paramCount + 1)
if longDataSize < 64 {
longDataSize = 64
}
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Maybe, 16byte is too short?


// Reset packet-sequence
mc.sequence = 0

Expand Down Expand Up @@ -1039,7 +1045,7 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
paramTypes[i+i] = byte(fieldTypeString)
paramTypes[i+i+1] = 0x00

if len(v) < mc.maxAllowedPacket-pos-len(paramValues)-(len(args)-(i+1))*64 {
if len(v) < longDataSize {
paramValues = appendLengthEncodedInteger(paramValues,
uint64(len(v)),
)
Expand All @@ -1061,7 +1067,7 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
paramTypes[i+i] = byte(fieldTypeString)
paramTypes[i+i+1] = 0x00

if len(v) < mc.maxAllowedPacket-pos-len(paramValues)-(len(args)-(i+1))*64 {
if len(v) < longDataSize {
paramValues = appendLengthEncodedInteger(paramValues,
uint64(len(v)),
)
Expand Down