Application is multithreaded but use 1 connection for each thread !

Massiv writing BlobFields via StoredProcedure ( sql insert not tested ) will end up in a exception in the fbclient.
example code for reproducing the problem.

if ( AMsg->Size < 8190 )
IBCSP_PutMailTemp->ParamByName("MessageShort")->AsString = AMsg->ToString();
else
IBCSP_PutMailTemp->ParamByName("Message")->LoadFromStream( AMsg , ftBlob);

  IBCSP_PutMailTemp->ExecProc();

When AMsg->Size lower 8190 bytes the SP use the VarChar Parameter.
So i can write without any problems 3200 rows in 152 seconds.
This work without any Problem more then 20 times with 3200 rows.

When i only use the Blob version without the if.
  IBCSP_PutMailTemp->ParamByName("Message")->LoadFromStream( AMsg , ftBlob);


I got an exception after 80-150 rows in the fbclient.dll.
The error message is "Invalid BLOB ID" and the debugger always catches it at the same position.

Here the sample database:

SET SQL DIALECT 3;
CREATE DOMAIN "d_BLOB_Text_Gross" AS
BLOB SUB_TYPE 1 SEGMENT SIZE 4096 CHARACTER SET UTF8;

CREATE DOMAIN "d_Akt_DatumZeit" AS
TIMESTAMP
DEFAULT current_timestamp;

CREATE DOMAIN "d_strMax" AS
VARCHAR(8191) CHARACTER SET UTF8
DEFAULT ''
COLLATE UTF8;

CREATE GENERATOR "GEN_E-MailNewIn_ID";
CREATE TABLE "E-MailNewIn" (
    "ENI_MaildID" BIGINT NOT NULL,
    "ENI_Message" "d_BLOB_Text_Gross",
    "ENI_Groesse" INTEGER,
    "ENI_Eingegangen" "d_Akt_DatumZeit"
);
ALTER TABLE "E-MailNewIn" ADD CONSTRAINT "PK_E-MailNewIn" PRIMARY KEY ("ENI_MaildID");

SET TERM ^ ;
/* Trigger: "E-MailNewIn_BI" */
CREATE OR ALTER TRIGGER "E-MailNewIn_BI" FOR "E-MailNewIn"
ACTIVE BEFORE INSERT POSITION 0
as
begin
  if (new."ENI_MaildID" is null) then
    new."ENI_MaildID" = gen_id("GEN_E-MailNewIn_ID",1);
end
^

create or alter procedure "NewMailIn" (
    "Message" "d_BLOB_Text_Gross",
    "MessageGroesse" integer,
    "MessageShort" "d_strMax" = null)
returns (
    "RetCode" integer)
as
begin
  if ( :"MessageShort" is not null ) then
    insert into "E-MailNewIn" ( "ENI_Message", "ENI_Groesse" ) values ( :"MessageShort" , :"MessageGroesse" );
  else
    insert into "E-MailNewIn" ( "ENI_Message", "ENI_Groesse" ) values ( :"Message" , :"MessageGroesse" );
  suspend;
end
^
SET TERM ; ^