1. A hydraulic actuator, comprising:
a hydraulic fluid reservoir locatable in a downhole environment of a wellbore;
a piezoelectric pump connected to said hydraulic fluid reservoir; and
a hydraulically operable device connected to said piezoelectric pump.
2. The hydraulic actuator of claim 1 wherein said piezoelectric pump is in communication with a power source.
3. The hydraulic actuator of claim 2 wherein said communication between said piezoelectric pump and said power source is electrical communication.
4. The hydraulic actuator of claim 2 wherein said communication between said piezoelectric pump and said power source is photo communication.
5. The hydraulic actuator of claim 4 wherein said photo communication is through a fiber optic cable.
6. A hydraulic actuator system, comprising:
a power source;
a controller remotely located from and in communication with said power source;
a piezoelectric stack in electrical communication with said controller, said piezoelectric stack comprising,
a sleeve, and
a plurality of piezoelectric elements disposed within said sleeve and being configured to define a chamber at an end of said sleeve, the volume of said chamber being a function of expansion of said piezoelectric elements;
a flow control valve in fluid communication with said chamber; and
a hydraulically actuatable device in fluid communication with said flow control valve.
7. The hydraulic actuator system of claim 6 wherein said hydraulically actuatable device comprises,
a high pressure environment in fluid communication with said chamber, and
a low pressure source in fluid communication with said chamber, and wherein said flow control valve is in fluid communication with said high pressure environment and said low pressure source.
8. The hydraulic actuator system of claim 6 wherein said communication between said power source and said controller is electrical communication.
9. The hydraulic actuator system of claim 6 wherein said communication between said power source and said controller is photo communication.
10. The hydraulic actuator system of claim 9 wherein said photo communication is through a fiber optic cable.
11. The hydraulic actuator system of claim 6 wherein said piezoelectric stack further comprises,
an inlet check valve disposed between said chamber and said hydraulically actuatable device to permit fluid flow into said chamber from said hydraulically actuatable device, and
an outlet check valve disposed between said chamber and said hydraulically actuatable device to permit fluid flow out of said chamber and into said hydraulically actuatable device.
12. The hydraulic actuator system of claim 6 wherein said flow control valve is controllable and configured to provide communication between said chamber and said hydraulically actuatable device to effectuate a movement of said hydraulically actuatable device.
13. The hydraulic actuator system of claim 12 wherein said hydraulically actuatable device is a hydraulic piston.
14. The hydraulic actuator system of claim 12 wherein said hydraulically actuatable device is a rotary actuatable device.
15. The hydraulic actuator system of claim 6 wherein each of said piezoelectric elements is of a prolate spheroid shape.
16. The hydraulic actuator system of claim 6 wherein said plurality of piezoelectric elements includes at least one piezoelectric element having a plate shape and at least one piezoelectric element having a prolate spheroid shape.
17. The hydraulic actuator system of claim 6 wherein each of said piezoelectric elements is fabricated from a material selected from the group consisting of lead zirconate titanate, barium titanate, quartz, tourmaline, and tartrate salts.
18. The hydraulic actuator system of claim 6 wherein said power source is located at a well head of a wellbore and wherein said controller, said piezoelectric stack, said flow control valve, and said hydraulically actuatable device are located in a downhole environment of said wellbore.
19. The hydraulic actuator system of claim 7 wherein said low pressure source is a low pressure accumulator.
20. The hydraulic actuator system of claim 7 wherein said low pressure source is a hydraulic control line.
21. The hydraulic actuator system of claim 7 wherein said low pressure source is a tubing string positioned within a wellbore.
22. The hydraulic actuator system of claim 7 wherein said low pressure source is an annulus of a wellbore.
23. A wellbore system, comprising:
a wellbore; and
a plurality of hydraulic actuators disposed within said wellbore, at least one of said plurality of hydraulic actuators comprising,
a hydraulic fluid reservoir locatable in a downhole environment of said wellbore,
a piezoelectric pump connected to said hydraulic fluid reservoir, and
a hydraulically actuatable device connected to said piezoelectric pump.
24. The wellbore system of claim 23 wherein at least two hydraulic actuators of said plurality of said hydraulic actuators are in communication with each other.
25. The wellbore system of claim 23 wherein said piezoelectric pump of said hydraulic actuator is in communication with a power source.
26. The wellbore system of claim 25 wherein said communication between said piezoelectric pump and said power source is electrical communication.
27. The wellbore system of claim 25 wherein said communication between said piezoelectric pump and said power source is photo communication.
28. The wellbore system of claim 27 wherein said photo communication is through a fiber optic cable.
29. A method for controlling a remotely located hydraulic actuator, comprising:
communicating a signal from a power source to a piezoelectric pump;
pressurizing a hydraulic fluid with said piezoelectric pump; and
directing said hydraulic fluid to a hydraulically actuatable device in said hydraulic actuator to bias a piston, thereby translating said piston in either a first or a second direction.
30. The method for controlling the remotely located hydraulic actuator of claim 29 wherein said communicating said signal further comprises transmitting a signal to a controller configured to effectuate the pressurization and direction of said hydraulic fluid to bias said piston.
31. The method for controlling the remotely located hydraulic actuator of claim 30 wherein said transmitting of said signal is through an electrical communication medium.
32. The method for controlling the remotely located hydraulic actuator of claim 30 wherein said transmitting of said signal is through a photo communication medium.
33. The method for controlling the remotely located hydraulic actuator of claim 28 wherein said pressurizing further comprises, expanding a piezoelectric element in said piezoelectric pump, decreasing a volume of a chamber in which a hydraulic fluid is disposed, creating a high pressure condition within said volume of said chamber, and causing said hydraulic fluid to flow out of said chamber.
34. The method for controlling the remotely located hydraulic actuator of claim 29 wherein said power source is located at a location remote from said hydraulic actuator.
35. The method for controlling the remotely located hydraulic actuator of claim 34 wherein said power source is located at a well head of a wellbore and said hydraulic actuator is located in a downhole environment of said wellbore.
36. A method for controlling one or more hydraulic cylinders connected to the hydraulic actuator of claim 1, comprising:
communicating a signal from a power source to said piezoelectric pump;
pressurizing a hydraulic fluid with said piezoelectric pump; and
directing said hydraulic fluid to a cylinder in said hydraulic actuator of claim 1 to bias a piston, thereby translating said cylinder in either a first or a second direction.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method comprising:
stabilizing a page of data that includes a record to be accessed in accordance with an access plan generated for executing a query, the query comprising a non-predicate filtering operation;
positioning a cursor on the record to be accessed;
applying the non-predicate filtering operation of the query to the record to determine whether the record is to be filtered under the non-predicate filtering operation while the page of data remains stabilized; and
in response to a determination that the record is to be filtered under the non-predicate filtering operation,
repositioning the cursor on a next record included in the page of data that is to be accessed in accordance with the access plan generated for executing the query without releasing stabilization of the page of data, and
applying the non-predicate filtering operation of the query to the next record to determine whether the next record is to be filtered under the non-predicate filtering operation while the page of data remains stabilized.
2. The method of claim 1, further comprising:
in response to a determination that the record is not to be filtered under the non-predicate filtering operation,
copying the record to a storage location for further processing in accordance with the access plan, and
releasing stabilization of the page of data.
3. The method of claim 2, further comprising:
further processing the copy of the record in the storage location in accordance with the access plan; and
returning a result for the query.
4. The method of claim 2, wherein the storage location is a processor buffer.
5. The method of claim 2, wherein the storage location is a location in memory.
6. The method of claim 1, wherein the non-predicate filtering operation is a DISINTCT operation.
7. A computer readable storage medium encoded with a computer program, the computer program comprising computer-executable instructions for:
stabilizing a page of data that includes a record to be accessed in accordance with an access plan generated for executing a query, the query comprising a non-predicate filtering operation;
positioning a cursor on the record to be accessed;
applying the non-predicate filtering operation of the query to the record to determine whether the record is to be filtered under the non-predicate filtering operation while the page of data remains stabilized; and
in response to a determination that the record is to be filtered under the non-predicate filtering operation,
repositioning the cursor on a next record included in the page of data that is to be accessed in accordance with the access plan generated for executing the query without releasing stabilization of the page of data, and
applying the non-predicate filtering operation of the query to the next record to determine whether the next record is to be filtered under the non-predicate filtering operation while the page of data remains stabilized.
8. The computer readable storage medium of claim 7, wherein the computer program further comprises computer-executable instructions for:
in response to a determination that the record is not to be filtered under the non-predicate filtering operation,
copying the record to a storage location for further processing in accordance with the access plan, and
releasing stabilization of the page of data.
9. The computer readable storage medium of claim 8, wherein the computer program further comprises computer-executable instructions for:
further processing the copy of the record in the storage location in accordance with the access plan; and
returning a result for the query.
10. The computer readable storage medium of claim 8, wherein the storage location is a processor buffer.
11. The computer readable storage medium of claim 8, wherein the storage location is a location in memory.
12. The computer readable storage medium of claim 7, wherein the non-predicate filtering operation is a DISINTCT operation.
13. A system comprising:
a data manager, the data manager
stabilizing a page of data that includes a record to be accessed in accordance with an access plan generated for executing a query, the query comprising a non-predicate filtering operation, and
positioning a cursor on the record to be accessed; and a query manager in communication with the data manager, the query manager
applying the non-predicate filtering operation of the query to the record to determine whether the record is qualifies under the non-predicate filtering operation while the page of data remains stabilized, and
indicating to the data manager that the record is to be filtered responsive to a determination that the record does not qualify under the non-predicate filtering operation,
in response to receiving the indication from the query manager that the record is to be filtered, the data manager
repositions the cursor on a next record included in the page of data that is to be accessed in accordance with the access plan generated for executing the query without releasing stabilization of the page of data, and
calls the query manager to apply the non-predicate filtering operation of the query to the next record without releasing stabilization of the page of data.
14. The system of claim 13, wherein the query manager indicates to the data manager that the record is not to be filtered responsive to a determination that the record qualifies under the non-predicate filtering operation,
in response to receiving the indication from the query manager that the record is not to be filtered, the data manager
copies the record to a storage location for further processing in accordance with the access plan, and
releases stabilization of the page of data.
15. The system of claim 14, wherein the query manager further
processes the copy of the record in the storage location in accordance with the access plan, and
returns a result for the query.
16. The system of claim 14, wherein the storage location is a processor buffer.
17. The system of claim 14, wherein the storage location is a location in memory.
18. The system of claim 13, wherein the non-predicate filtering operation is a DISINTCT operation.