SQLBulkOperations Segfault

[Jeremy Faith <jfaith(at)cemsys(dot)com>]

Hi,

I have been experimenting with SQLBulkOperations to see if it is faster 
at inserting rows than using individual insert statements.
But when I run the attached(bo.c) example program it segfaults(note, 
this program works correctly with an Oracle ODBC connection).

The program requires the following table.
 create table customer
 (
   cust_num integer not null,
   first_name char(20),
   last_name char(20)
 );

Also the odb_db_open function call uses a hard coded DSN=pg_cdc_w, 
username=username and password=password.

I am using the latest versions of pgsql+postgres on Linux i.e.
 psqlodbc-08.03.0100
 postgresql-8.3.1

I turned on the ODBC debug log and added some log output to the driver 
and found that the segfault is occurring in the results.c:SC_pos_add 
function.

In particular the log shows
 POS ADD fi=(nil) ti=(nil)

and the segfault occurs on this line:-
                       if (*used != SQL_IGNORE && fi[i]->updatable)
So fi is NULL but is being referenced.

I did a bit more checking and found that parse_statement sets up 
stmt->ird->irdopts.fi i.e.
       if (SC_update_not_ready(stmt))
               parse_statement(s.stmt, TRUE);  /* not preferable */
so adding
 fi=stmt->ird->irdopts.fi;
after parse_statement gets past this segfault.

But then another segfault occurs in the results.c:positioned_load 
function as stmt->load_stmt is NULL
 so strlen(stmt->load_stmt) segfaults.

The code is complicated and I have not been able to determine how to fix 
this, it seems likely to me that even the fi fix may be covering up an 
earlier problem somewhere else in the code.

Does anybody use SQLBulkOperations to load data?
If so is it faster than individual inserts?

The postgres driver included with unixODBC fails as well but it at least 
return a standard ODBC error so I suppose it doesn't support 
SQLBulkOperations, I understand the unixODBC driver is defunct anyway.

I have noticed that the unixODBC postgres driver is significantly 
quicker when using a prepared insert to insert 100,000 rows. 
Specifically psqlodbc takes about 75% longer, but this is reduced to 
about 45% longer when 'UseServerSidePrepare = 1' is set. Indeed it was 
this speed difference that prompted me to try SQLBulkOperation in the 
first place.
Are there any other setting that may improve the speed of the psqlodbc 
driver?
Any ideas why the old unixODBC driver is so much faster?

Regards,
Jeremy Faith

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <sqlext.h>

#ifndef TRUE
  #define TRUE 1
#endif
                                                                                
#ifndef FALSE
  #define FALSE 0
#endif

#define ELOG );
#define LOGT fprintf(stderr,
#define LOGE fprintf(stderr,

struct odb_con_struct
{
  SQLHENV sqlenv;
  SQLHDBC sqlcon;
}*con;

void odb_err(SQLHSTMT stmt,int doexit,char *sql,char *msg);

SQLHSTMT odb_stmt(void)
{
  SQLHSTMT stmt;
                                                                                
  if(con==NULL||con->sqlcon==NULL)
  { 
    LOGE "odb_stmt:no DB connection\n" ELOG
    exit(1);
  }
  if(SQLAllocStmt(con->sqlcon,&stmt)!=SQL_SUCCESS)
    odb_err(stmt,TRUE,NULL,"SQLAllocStmt failed");
  return stmt;
}
                                                                                
void odb_stmt_free(SQLHSTMT stmt)
{
  if(stmt!=NULL) SQLFreeHandle(SQL_HANDLE_STMT,stmt);
}

void odb_db_close()
{
  SQLRETURN ret;
  LOGT "odb_db_close:\n" ELOG
  if(con==NULL) return;
  if(con->sqlcon!=NULL)
  {
    ret=SQLDisconnect(con->sqlcon);
    if(ret!=SQL_SUCCESS&&ret!=SQL_SUCCESS_WITH_INFO)
      odb_err(NULL,FALSE,NULL,"odb_db_close");
    SQLFreeHandle(SQL_HANDLE_DBC,con->sqlcon);
  }
  if(con->sqlenv!=NULL) SQLFreeHandle(SQL_HANDLE_ENV,con->sqlenv);
  free(con);
  con=NULL;
}

void odb_cleanup(int doexit,SQLHSTMT stmt)
{
  odb_stmt_free(stmt);
  odb_db_close();
  if(doexit) exit(13);
}

void odb_err(SQLHSTMT stmt,int doexit,char *sql,char *msg)
{
  SQLCHAR err[501];
  SQLCHAR state[10];
  SQLINTEGER native_err;
  SQLSMALLINT msg_len;
                                                                                
  LOGE "odb_err:%s\n%s\n",(sql==NULL)?"":sql,msg ELOG
  if(con==NULL)
  {
    LOGE "odb_err:no DB connection\n" ELOG
    exit(1);
  }
  if(stmt!=NULL)
    while(SQLError(con->sqlenv,con->sqlcon,stmt,state,&native_err,err,
           sizeof(err)-1,&msg_len)==SQL_SUCCESS)
    {
      LOGE "stmt native_err=%ld [%s]%s\n",native_err,state,err ELOG
    }
  if(con->sqlcon!=NULL)
    while(SQLError(con->sqlenv,con->sqlcon,NULL,state,&native_err,err,
      sizeof(err)-1,&msg_len)==SQL_SUCCESS)
    {
      LOGE "con native_err=%ld [%s]%s\n",native_err,state,err ELOG
    }
  if(con->sqlenv!=NULL)
    while(SQLError(con->sqlenv,NULL,NULL,state,&native_err,err,sizeof(err)-1,
      &msg_len)==SQL_SUCCESS)
    {
      LOGE "env native_err=%ld [%s]%s\n",native_err,state,err ELOG
    }
  if(doexit) odb_cleanup(TRUE,stmt);
}


void odb_db_open(char *dsn,char *uid,char *pwd)
{
  if(SQLAllocEnv(&con->sqlenv)!=SQL_SUCCESS)
    odb_err(NULL,TRUE,NULL,"odb_db_open:SQLAllocEnv failed");
  if(SQLAllocConnect(con->sqlenv,&con->sqlcon)!=SQL_SUCCESS)
    odb_err(NULL,TRUE,NULL,"SQLAllocConnect failed");
  if(!SQL_SUCCEEDED(SQLConnect(con->sqlcon,(SQLCHAR *)dsn,SQL_NTS,
      (SQLCHAR *)uid,SQL_NTS,(SQLCHAR *)pwd,SQL_NTS)))
    odb_err(NULL,TRUE,NULL,"SQLConnect failed");
  LOGT "odb_db_open:SQLconnect ok\n" ELOG
}



void bulk_load()
{
  #define ROWSET_SIZE 100
  SQLCHAR sqlstmt[] =
    "select cust_num,first_name,last_name from customer";
  struct cust_struct
  {
    SQLINTEGER cust_num;
    SQLINTEGER cust_num_i;
    SQLCHAR first_name[21];
    SQLINTEGER first_name_i;
    SQLCHAR last_name[21];
    SQLINTEGER last_name_i;
  }cust[ROWSET_SIZE];
  SQLUSMALLINT status[ROWSET_SIZE];
  SQLHSTMT stmt=odb_stmt();
  int i;
  SQLRETURN ret;
  
  ret=SQLExecDirect(stmt,sqlstmt,SQL_NTS);
  if(ret!=SQL_SUCCESS)
    odb_err(stmt,TRUE,NULL,"SQLExecDirect");

  //set size of one row
  ret=SQLSetStmtAttr(stmt,SQL_ATTR_ROW_BIND_TYPE,
    (SQLPOINTER)sizeof(struct cust_struct),0);
  if(ret!=SQL_SUCCESS)
    odb_err(stmt,TRUE,NULL,"SQL_ATTR_ROW_BIND_TYPE");
  //set pointer to row status array
  ret=SQLSetStmtAttr(stmt,SQL_ATTR_ROW_STATUS_PTR,(SQLPOINTER)status,0);
  if(ret!=SQL_SUCCESS)
    odb_err(stmt,TRUE,NULL,"SQL_ATTR_ROW_STATUS_PTR");

  //bind data
  SQLBindCol(stmt,1,SQL_C_LONG,(SQLPOINTER)&cust[0].cust_num,
    (SQLINTEGER)sizeof(SQLINTEGER),&cust[0].cust_num_i);
  SQLBindCol(stmt,2,SQL_C_CHAR,(SQLPOINTER)cust[0].first_name,
    (SQLINTEGER)21,&cust[0].first_name_i);
  SQLBindCol(stmt,3,SQL_C_CHAR,(SQLPOINTER)cust[0].last_name,
    (SQLINTEGER)21,&cust[0].last_name_i);
  //make data
  for(i=0;i<ROWSET_SIZE;i++)
  {
    cust[i].cust_num=i;
    cust[i].cust_num_i=0;
    sprintf(cust[i].first_name,"FN%d",i);
    cust[i].first_name_i=SQL_NTS;
    sprintf(cust[i].last_name,"LN%d",i);
    cust[i].last_name_i=SQL_NTS;
  }
  //set number of rows to insert
  ret=SQLSetStmtAttr(stmt,SQL_ATTR_ROW_ARRAY_SIZE,(SQLPOINTER)ROWSET_SIZE,0);
  if(ret!=SQL_SUCCESS)
    odb_err(stmt,TRUE,NULL,"SQL_ATTR_ROW_ARRAY_SIZE");
  LOGT "Before SQLBulkOperations\n" ELOG
  ret=SQLBulkOperations(stmt,SQL_ADD);
  LOGT "SQLBulkOperations ret=%d\n",ret ELOG
  if(ret!=SQL_SUCCESS)
    odb_err(stmt,TRUE,NULL,"SQLBulkOperations Failed");
}

int main(int argc,char **argv)
{
  con=malloc(sizeof(*con));
  odb_db_open("pg_cdc_w","username","password");
//  odb_db_open("ora_cdc","cem","cem");
  bulk_load();
  odb_cleanup(FALSE,NULL);
  return 0;
}

/*
  DB must have following table
  create table customer
  (
    cust_num integer not null,
    first_name char(20),
    last_name char(20) 
  );
*/