[defect] insert lob with size more or equal to 8192 will fail

[haiquanli-sap]

I think this is a bug in current version of github.com/SAP/go-hdb v1.1.5
It works with 1.1.3 but not 1.1.5.

I made an experiment that when we insert a lob data that length >= 8192, it will fail with message :"Repository Error: Executing Statement List, protocol error: invalid number of lob parameter ids 1"

The callstack is:
github.com/SAP/go-hdb/driver.(*conn).encodeLobs(0xc000478230, 0x0, {0xc0006d6f48, 0x1, 0x1}, {0xc0007a8000, 0x1c, 0x0?}, {0xc00007c000, 0x1c, ...})
/go/src/github.wdf.sap.corp/bdh/rms/vendor/github.com/SAP/go-hdb/driver/connection.go:1716 +0x43a
github.com/SAP/go-hdb/driver.(*conn)._execBatch(0xc000478230, 0xc0006edd00, {0xc00007c000, 0x1c, 0x1c}, 0x1c?, 0x0)
/go/src/github.wdf.sap.corp/bdh/rms/vendor/github.com/SAP/go-hdb/driver/connection.go:1346 +0x52f
github.com/SAP/go-hdb/driver.(*conn)._exec(0xc000478230, 0xc0006edd00, {0xc00007c000?, 0x1c, 0x1c}, 0x0?, 0x1586500?)
/go/src/github.wdf.sap.corp/bdh/rms/vendor/github.com/SAP/go-hdb/driver/connection.go:1297 +0x319
github.com/SAP/go-hdb/driver.(*stmt).exec(0xc00064e900, {0xc00007c000, 0x1c, 0x1c})
/go/src/github.wdf.sap.corp/bdh/rms/vendor/github.com/SAP/go-hdb/driver/connection.go:748 +0x43c
github.com/SAP/go-hdb/driver.(*stmt).ExecContext.func1()
/go/src/github.wdf.sap.corp/bdh/rms/vendor/github.com/SAP/go-hdb/driver/connection.go:703 +0x206
created by github.com/SAP/go-hdb/driver.(*stmt).ExecContext
/go/src/github.wdf.sap.corp/bdh/rms/vendor/github.com/SAP/go-hdb/driver/connection.go:699 +0x53a

Our developer debugged the code and found that:

I went through the code and they have a bug. LOBs that are < 8192 are sent in-line it looks like, only when you reach size 8192 does it generate a locator ID. At that point, it goes into a loop of all fields and if that field is a LOB, it expects it to have an ID, but we have 6 LOBs (1 size 8192, 5 size < 8192). So there is only 1 locator ID and when it gets to that next LOB field, it throws that error because it expects an ID to be present.

In 1.1.3 the code returned 6 locator IDs. So looks like they added logic to allow smaller lobs not to return locator IDs but forgot to fix the loop that looks for them.

File a bug with them and don't upgrade to 1.1.5 until it is fixed.

The issue is in connection.go:

func (c *conn) encodeLobs(cr *callResult, ids []p.LocatorID, inPrmFields []*p.ParameterField, nvargs []driver.NamedValue) error {
in this for loop:

for i, f := range inPrmFields {

If it makes it in there, it expects every Lob field to have a locator ID.

It seems to be an issue from perf changes in 1.1.4 31ceb2e#diff-5265516ccba5c11855cd41ea179d0bb050bab7d61b0b57509e180bf846edf13b

[stfnmllr]

Thanks for raising! Was able to reproduce the issue but v1.1.3 is affected as well. Anyway,
https://github.com/SAP/go-hdb/releases/tag/v1.1.6
should fix it.