- Add a configurable non-negative
session parameter "sql_vdbe_max_steps"
-- max number of opcodes that Vdbe
is allowed to execute for sql query.

- Default value can be specified in box.cfg.
If not set via box.cfg, default value
is 45000. Value 0 means that no
checks for number of executed Vdbe
opcodes will be made.

- Add the third argument to box.execute
function, that allows to specify options
for query execution. The only option
supported: sql_vdbe_max_steps. Usage
example:

```
box.execute([[select * from t]], {}, {{sql_vdbe_max_steps = 1000}})
```

part of picodata/picodata/sbroad!461

NO_DOC=picodata internal patch
NO_CHANGELOG=picodata internal patch