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Overview
Comment:Experimental sqlite3_stmt_retryable() interface.
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Timelines: family | ancestors | sqlite3_stmt_retryable
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SHA3-256: ebada0723ac91f288fe89baf4a7eb6383f71d6588afaf17467f45a56677de22d
User & Date: drh 2017-09-13 18:38:31
Context
2017-09-13
18:38
Experimental sqlite3_stmt_retryable() interface. Leaf check-in: ebada072 user: drh tags: sqlite3_stmt_retryable
12:55
Disable FTS3 matchinfo() tests that assume a littleEndian platform when running on bigEndian. check-in: 87ccdf9c user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/main.c.

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**
** This routine is called when an operation failed with a lock.
** If this routine returns non-zero, the lock is retried.  If it
** returns 0, the operation aborts with an SQLITE_BUSY error.
*/
int sqlite3InvokeBusyHandler(BusyHandler *p){
  int rc;
  if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;



  rc = p->xFunc(p->pArg, p->nBusy);
  if( rc==0 ){

    p->nBusy = -1;
  }else{
    p->nBusy++;
  }
  return rc; 
}








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**
** This routine is called when an operation failed with a lock.
** If this routine returns non-zero, the lock is retried.  If it
** returns 0, the operation aborts with an SQLITE_BUSY error.
*/
int sqlite3InvokeBusyHandler(BusyHandler *p){
  int rc;
  if( p->xFunc==0 || p->nBusy<0 ){
    p->nTimeout++;
    return 0;
  }
  rc = p->xFunc(p->pArg, p->nBusy);
  if( rc==0 ){
    p->nTimeout++;
    p->nBusy = -1;
  }else{
    p->nBusy++;
  }
  return rc; 
}

Changes to src/shell.c.

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  int (*xCallback)(void*,int,char**,char**,int*),   /* Callback function */
                                            /* (not the same as sqlite3_exec) */
  ShellState *pArg,                         /* Pointer to ShellState */
  char **pzErrMsg                           /* Error msg written here */
){
  sqlite3_stmt *pStmt = NULL;     /* Statement to execute. */
  int rc = SQLITE_OK;             /* Return Code */
  int rc2;
  const char *zLeftover;          /* Tail of unprocessed SQL */

  if( pzErrMsg ){
    *pzErrMsg = NULL;
  }

  while( zSql[0] && (SQLITE_OK == rc) ){
................................................................................
      if( pArg && pArg->scanstatsOn ){
        display_scanstats(db, pArg);
      }

      /* Finalize the statement just executed. If this fails, save a
      ** copy of the error message. Otherwise, set zSql to point to the
      ** next statement to execute. */

      rc2 = sqlite3_finalize(pStmt);
      if( rc!=SQLITE_NOMEM ) rc = rc2;
      if( rc==SQLITE_OK ){
        zSql = zLeftover;
        while( IsSpace(zSql[0]) ) zSql++;








      }else if( pzErrMsg ){
        *pzErrMsg = save_err_msg(db);

      }

      /* clear saved stmt handle */
      if( pArg ){
        pArg->pStmt = NULL;
      }
    }







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  int (*xCallback)(void*,int,char**,char**,int*),   /* Callback function */
                                            /* (not the same as sqlite3_exec) */
  ShellState *pArg,                         /* Pointer to ShellState */
  char **pzErrMsg                           /* Error msg written here */
){
  sqlite3_stmt *pStmt = NULL;     /* Statement to execute. */
  int rc = SQLITE_OK;             /* Return Code */
  int rc2, rc3;
  const char *zLeftover;          /* Tail of unprocessed SQL */

  if( pzErrMsg ){
    *pzErrMsg = NULL;
  }

  while( zSql[0] && (SQLITE_OK == rc) ){
................................................................................
      if( pArg && pArg->scanstatsOn ){
        display_scanstats(db, pArg);
      }

      /* Finalize the statement just executed. If this fails, save a
      ** copy of the error message. Otherwise, set zSql to point to the
      ** next statement to execute. */
      rc3 = sqlite3_stmt_retryable(pStmt);
      rc2 = sqlite3_finalize(pStmt);
      if( rc!=SQLITE_NOMEM ) rc = rc2;
      if( rc==SQLITE_OK ){
        zSql = zLeftover;
        while( IsSpace(zSql[0]) ) zSql++;
      }else{
        if( rc==SQLITE_BUSY ){
          if( rc3 ){
            raw_printf(pArg->out, "Busy: might succeed on retry\n");
          }else{
            raw_printf(pArg->out, "Busy: cannot succeed - rollback required\n");
          }
        }
        if( pzErrMsg ){
          *pzErrMsg = save_err_msg(db);
        }
      }

      /* clear saved stmt handle */
      if( pArg ){
        pArg->pStmt = NULL;
      }
    }

Changes to src/shell.c.in.

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  int (*xCallback)(void*,int,char**,char**,int*),   /* Callback function */
                                            /* (not the same as sqlite3_exec) */
  ShellState *pArg,                         /* Pointer to ShellState */
  char **pzErrMsg                           /* Error msg written here */
){
  sqlite3_stmt *pStmt = NULL;     /* Statement to execute. */
  int rc = SQLITE_OK;             /* Return Code */
  int rc2;
  const char *zLeftover;          /* Tail of unprocessed SQL */

  if( pzErrMsg ){
    *pzErrMsg = NULL;
  }

  while( zSql[0] && (SQLITE_OK == rc) ){
................................................................................
      if( pArg && pArg->scanstatsOn ){
        display_scanstats(db, pArg);
      }

      /* Finalize the statement just executed. If this fails, save a
      ** copy of the error message. Otherwise, set zSql to point to the
      ** next statement to execute. */

      rc2 = sqlite3_finalize(pStmt);
      if( rc!=SQLITE_NOMEM ) rc = rc2;
      if( rc==SQLITE_OK ){
        zSql = zLeftover;
        while( IsSpace(zSql[0]) ) zSql++;








      }else if( pzErrMsg ){
        *pzErrMsg = save_err_msg(db);

      }

      /* clear saved stmt handle */
      if( pArg ){
        pArg->pStmt = NULL;
      }
    }







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  int (*xCallback)(void*,int,char**,char**,int*),   /* Callback function */
                                            /* (not the same as sqlite3_exec) */
  ShellState *pArg,                         /* Pointer to ShellState */
  char **pzErrMsg                           /* Error msg written here */
){
  sqlite3_stmt *pStmt = NULL;     /* Statement to execute. */
  int rc = SQLITE_OK;             /* Return Code */
  int rc2, rc3;
  const char *zLeftover;          /* Tail of unprocessed SQL */

  if( pzErrMsg ){
    *pzErrMsg = NULL;
  }

  while( zSql[0] && (SQLITE_OK == rc) ){
................................................................................
      if( pArg && pArg->scanstatsOn ){
        display_scanstats(db, pArg);
      }

      /* Finalize the statement just executed. If this fails, save a
      ** copy of the error message. Otherwise, set zSql to point to the
      ** next statement to execute. */
      rc3 = sqlite3_stmt_retryable(pStmt);
      rc2 = sqlite3_finalize(pStmt);
      if( rc!=SQLITE_NOMEM ) rc = rc2;
      if( rc==SQLITE_OK ){
        zSql = zLeftover;
        while( IsSpace(zSql[0]) ) zSql++;
      }else{
        if( rc==SQLITE_BUSY ){
          if( rc3 ){
            raw_printf(pArg->out, "Busy: might succeed on retry\n");
          }else{
            raw_printf(pArg->out, "Busy: cannot succeed - rollback required\n");
          }
        }
        if( pzErrMsg ){
          *pzErrMsg = save_err_msg(db);
        }
      }

      /* clear saved stmt handle */
      if( pArg ){
        pArg->pStmt = NULL;
      }
    }

Changes to src/sqlite.h.in.

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** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
** sqlite3_stmt_readonly() returns false for those commands.
*/
int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);













/*
** CAPI3REF: Determine If A Prepared Statement Has Been Reset
** METHOD: sqlite3_stmt
**
** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
** [prepared statement] S has been stepped at least once using 
** [sqlite3_step(S)] but has neither run to completion (returned







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** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
** sqlite3_stmt_readonly() returns false for those commands.
*/
int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);

/*
** CAPI3REF: Determine If An SQL Statement Can Be Retried After SQLITE_BUSY
** METHOD: sqlite3_stmt
**
** ^The sqlite3_stmt_retryable(X) interface returns true (non-zero) if
** the previous run of [prepared statement] X failed with an
** [SQLITE_BUSY] error but might succeed if run again.  If X has not been
** previously run or if the previous run of X did not return SQLITE_BUSY,
** then the result of this function is a meaningless boolean.
*/
int sqlite3_stmt_retryable(sqlite3_stmt *pStmt);

/*
** CAPI3REF: Determine If A Prepared Statement Has Been Reset
** METHOD: sqlite3_stmt
**
** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
** [prepared statement] S has been stepped at least once using 
** [sqlite3_step(S)] but has neither run to completion (returned

Changes to src/sqliteInt.h.

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** callback is currently invoked only from within pager.c.
*/
typedef struct BusyHandler BusyHandler;
struct BusyHandler {
  int (*xFunc)(void *,int);  /* The busy callback */
  void *pArg;                /* First arg to busy callback */
  int nBusy;                 /* Incremented with each busy call */

};

/*
** Name of the master database table.  The master database table
** is a special table that holds the names and attributes of all
** user tables and indices.
*/







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** callback is currently invoked only from within pager.c.
*/
typedef struct BusyHandler BusyHandler;
struct BusyHandler {
  int (*xFunc)(void *,int);  /* The busy callback */
  void *pArg;                /* First arg to busy callback */
  int nBusy;                 /* Incremented with each busy call */
  u32 nTimeout;              /* Number of timeouts */
};

/*
** Name of the master database table.  The master database table
** is a special table that holds the names and attributes of all
** user tables and indices.
*/

Changes to src/vdbeInt.h.

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  bft doingRerun:1;       /* True if rerunning after an auto-reprepare */
  bft explain:2;          /* True if EXPLAIN present on SQL command */
  bft changeCntOn:1;      /* True to update the change-counter */
  bft runOnlyOnce:1;      /* Automatically expire on reset */
  bft usesStmtJournal:1;  /* True if uses a statement journal */
  bft readOnly:1;         /* True for statements that do not write */
  bft bIsReader:1;        /* True for statements that read */

  yDbMask btreeMask;      /* Bitmask of db->aDb[] entries referenced */
  yDbMask lockMask;       /* Subset of btreeMask that requires a lock */
  u32 aCounter[7];        /* Counters used by sqlite3_stmt_status() */
  char *zSql;             /* Text of the SQL statement that generated this */
  void *pFree;            /* Free this when deleting the vdbe */
  VdbeFrame *pFrame;      /* Parent frame */
  VdbeFrame *pDelFrame;   /* List of frame objects to free on VM reset */







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  bft doingRerun:1;       /* True if rerunning after an auto-reprepare */
  bft explain:2;          /* True if EXPLAIN present on SQL command */
  bft changeCntOn:1;      /* True to update the change-counter */
  bft runOnlyOnce:1;      /* Automatically expire on reset */
  bft usesStmtJournal:1;  /* True if uses a statement journal */
  bft readOnly:1;         /* True for statements that do not write */
  bft bIsReader:1;        /* True for statements that read */
  bft retryable:1;        /* True if the statement might succeed next time */
  yDbMask btreeMask;      /* Bitmask of db->aDb[] entries referenced */
  yDbMask lockMask;       /* Subset of btreeMask that requires a lock */
  u32 aCounter[7];        /* Counters used by sqlite3_stmt_status() */
  char *zSql;             /* Text of the SQL statement that generated this */
  void *pFree;            /* Free this when deleting the vdbe */
  VdbeFrame *pFrame;      /* Parent frame */
  VdbeFrame *pDelFrame;   /* List of frame objects to free on VM reset */

Changes to src/vdbeapi.c.

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/*
** Return true if the prepared statement is guaranteed to not modify the
** database.
*/
int sqlite3_stmt_readonly(sqlite3_stmt *pStmt){
  return pStmt ? ((Vdbe*)pStmt)->readOnly : 1;
}









/*
** Return true if the prepared statement is in need of being reset.
*/
int sqlite3_stmt_busy(sqlite3_stmt *pStmt){
  Vdbe *v = (Vdbe*)pStmt;
  return v!=0 && v->magic==VDBE_MAGIC_RUN && v->pc>=0;







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/*
** Return true if the prepared statement is guaranteed to not modify the
** database.
*/
int sqlite3_stmt_readonly(sqlite3_stmt *pStmt){
  return pStmt ? ((Vdbe*)pStmt)->readOnly : 1;
}

/*
** Return true if the prepared statement failed with SQLITE_BUSY on its
** previous run but might succeed if tried again.
*/
int sqlite3_stmt_retryable(sqlite3_stmt *pStmt){
  return pStmt ? ((Vdbe*)pStmt)->retryable : 0;
}

/*
** Return true if the prepared statement is in need of being reset.
*/
int sqlite3_stmt_busy(sqlite3_stmt *pStmt){
  Vdbe *v = (Vdbe*)pStmt;
  return v!=0 && v->magic==VDBE_MAGIC_RUN && v->pc>=0;

Changes to src/vdbeaux.c.

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          }
          rc = SQLITE_CONSTRAINT_FOREIGNKEY;
        }else{ 
          /* The auto-commit flag is true, the vdbe program was successful 
          ** or hit an 'OR FAIL' constraint and there are no deferred foreign
          ** key constraints to hold up the transaction. This means a commit 
          ** is required. */

          rc = vdbeCommit(db, p);

        }
        if( rc==SQLITE_BUSY && p->readOnly ){
          sqlite3VdbeLeave(p);
          return SQLITE_BUSY;
        }else if( rc!=SQLITE_OK ){
          p->rc = rc;
          sqlite3RollbackAll(db, SQLITE_OK);







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          }
          rc = SQLITE_CONSTRAINT_FOREIGNKEY;
        }else{ 
          /* The auto-commit flag is true, the vdbe program was successful 
          ** or hit an 'OR FAIL' constraint and there are no deferred foreign
          ** key constraints to hold up the transaction. This means a commit 
          ** is required. */
          db->busyHandler.nTimeout = 0;
          rc = vdbeCommit(db, p);
          p->retryable = db->busyHandler.nTimeout>0;
        }
        if( rc==SQLITE_BUSY && p->readOnly ){
          sqlite3VdbeLeave(p);
          return SQLITE_BUSY;
        }else if( rc!=SQLITE_OK ){
          p->rc = rc;
          sqlite3RollbackAll(db, SQLITE_OK);