Author: claimsbot

1. A photosensitive composition comprising (A) a resin increasing the solubility in an alkaline developer by the action of an acid, wherein the resin (A) comprises at least one repeating unit selected from the group consisting of:
(a) a repeating unit comprising: at least one of a hydroxyl group and a group where a hydrogen atom of a hydroxyl group is substituted with a group selected from an acyl group, an alkyl group, a cycloalkyl group and an acid decomposable group; and a group having a lactone structure; and
(b) a repeating unit comprising a group having a lactone structure, in which a 5- or 6-membered ring is fused.
2. The photosensitive composition according to claim 1, wherein the resin (A) comprises a repeating unit having at least one structure selected from structures represented by the following general formulae (I) to (III):
wherein
X represents \u2014CH2\u2014, an oxygen atom, a sulfur atom, or \u2014C(\u2550O)\u2014,
Lc represents a group for forming a lactone,
Ra1 and Ra2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or an acid decomposable group,
Ra3 represents a carboxyl group, an alkyl group, an alkoxy group, an acyloxy group, an alkoxycarbonyl group, or a group having an acid decomposable group,
two of Ra1 to Ra3 may combine together to form a ring,
X1 represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014,
n represents an integer of 1 or 2,
n1 and n2 each represents an integer of from 0 to 3, with proviso that (n, +n2) represents an integer of from 1 to 6, and
n3 represents an integer of from 0 to 3.
3. The photosensitive composition according to claim 1, wherein the resin (A) comprises a repeating unit containing at least one structure selected from structures represented by the following general formulae (I\u2032) to (III\u2032):
wherein Ra1 and Ra2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group or an acid decomposable group,
Ra1 and Ra2 may combine together to form a ring, and
X1 represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014.
4. The photosensitive composition according to claim 1, wherein the resin (A) comprises at least one repeating unit selected from repeating units represented by the following general formulae (Ia) to (IIIa):
wherein
Rb1 represents a hydrogen atom, an alkyl group or \u2014CH2\u2014O\u2014Rb2, wherein Rb2 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or a group having a lactone structure,
Rc represents a single bond or a divalent connecting group,
X represents \u2014CH2\u2014, an oxygen atom, a sulfur atom, or \u2014C(\u2550O)\u2014,
Lc represents a group for forming a lactone,
Ra1 and Ra2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or an acid decomposable group,
Ra3 represents a carboxyl group, an alkyl group, an alkoxy group, an acyloxy group, an alkoxycarbonyl group, or a group having an acid decomposable group,
two of Ra1 to Ra3 may combine together to form a ring,
X1 represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014,
n represents an integer of 1 or 2,
n1 and n2 each represents an integer of from 0 to 3, with proviso that (n, +n2) represents an integer of from 1 to 6, and
n3 represents an integer of from 0 to 3.
5. The photosensitive composition according to claim 1, wherein the resin (A) comprises at least one repeating unit selected from repeating units represented by the following general formulae (Ia-1) to (IIIa-1):
wherein
Rb1 represents a hydrogen atom, an alkyl group, or \u2014CH2\u2014O\u2014Rb2a, wherein Rb2a represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or a group having a lactone structure,
Rc represents a single bond or a divalent connecting group,
Ra1 and Ra2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or an acid decomposable group,
Ra3 represents a carboxyl group, an alkyl group, an alkoxy group, an acyloxy group, an alkoxycarbonyl group, or a group having an acid decomposable group,
two of Ra1 to Ra3 may combine together to form a ring,
X2 represents a single bond or \u2014CH2\u2014,
X3 represents a single bond or \u2014CH2\u2014,
X4 represents a single bond, \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014,
X5 represents a single bond, \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014,
the sum of the number of atoms exclusive of a hydrogen atom of X4 and X5 is 1 or 2, and
n3 represents an integer of from 0 to 3.
6. The photosensitive composition according to claim 1, wherein the resin (A) comprises at least one repeating unit selected from repeating units represented by the following general formulae (Ia\u2033), (IIa\u2032), (IIa\u2033), (IIIa\u2032) and (IIIa\u2033):
wherein
Rb1 represents a hydrogen atom, an alkyl group, or \u2014CH2\u2014O\u2014Rb2a, wherein Rb2a represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or a group having a lactone structure,
Rc represents a single bond or a divalent connecting group,
Ra1 and Ra2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or an acid decomposable group,
Ra1 and Ra2 may combine together to form a ring,
X1 represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014,
Y2 and Y3 each independently represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014O\u2014, or \u2014S\u2014,
Rb2, Rb3, and Rb4 each independently represents a hydrogen atom, an alkyl group, a hydroxyl group, a carboxyl group, or an alkoxycarbonyl group,
n4 represents 0 or 1.
7. A resin having at least one repeating unit selected from repeating units having a structure represented by the following general formulae (I\u2032) to (III\u2032):
wherein
Ra1 and Ra2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or an acid decomposable group,
Ra1 and Ra2 may combine together to form a ring, and
X1 represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014.
8. A resin having at least one repeating unit selected from repeating units represented by the following general formulae (Ia) to (IIIa):
wherein
Rb1 represents a hydrogen atom, an alkyl group, or \u2014CH2\u2014O\u2014Rb2a, wherein Rb2a represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or a group having a lactone structure,
Rc represents a single bond or a divalent connecting group,
X represents \u2014CH2\u2014, an oxygen atom, a sulfur atom, or \u2014C(\u2550O)\u2014,
Lc represents a group for forming a lactone,
Ra1 and Ra2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or an acid decomposable group,
Ra3 represents a carboxyl group, an alkyl group, an alkoxy group, an acyloxy group, an alkoxycarbonyl group, or a group having an acid decomposable group,
two of Ra1 to Ra3 may combine together to form a ring,
X1 represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014,
n represents an integer of 1 or 2,
n1 and n2 each represents an integer of from 0 to 3, with proviso that (n1+n2) represents an integer of from 1 to 6, and
n3 represents an integer of from 0 to 3.
9. A resin having at least one repeating unit selected from repeating units represented by the following general formulae (Ia\u2032), (Ia\u2033), (Iha\u2032), (IIa\u2033), (IIIa\u2032) and (IIIa\u2033):
wherein
Rb1 represents a hydrogen atom, an alkyl group, or \u2014CH2\u2014O\u2014Rb2a, wherein Rb2a represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or a group having a lactone structure,
Rc represents a single bond or a divalent connecting group,
Ra1 and Ra2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or an acid decomposable group,
Ra1 and Ra2 may combine together to form a ring,
X1 represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014,
Y2 and Y3 each independently represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014O\u2014, or \u2014S\u2014,
Rb2, Rb3, and Rb4 each independently represents a hydrogen atom, an alkyl group, a hydroxyl group, a carboxyl group, or an alkoxycarbonyl group, and
n4 represents 0 or 1.
10. A polymerizable compound containing a structure represented by any one of the following general formulae (I\u2032) to (III\u2032):
wherein
Ra1 and Ra2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or an acid decomposable group,
Ra1 and Ra2 may combine together to form a ring, and
X1 represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014.
11. A polymerizable compound represented by any one of the following general formulae (Ib) to (IIIb):
wherein
Rb1 represents a hydrogen atom, an alkyl group, or \u2014CH2\u2014O\u2014Rb2a, wherein Rb2a represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or a group having a lactone structure,
Rc represents a single bond or a divalent connecting group,
X represents \u2014CH2\u2014, an oxygen atom, a sulfur atom, or \u2014C(\u2550O)\u2014,
Lc represents a group for forming a lactone,
Ra1 and Ra2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or an acid decomposable group,
Ra3 represents a carboxyl group, an alkyl group, an alkoxy group, an acyloxy group, an alkoxycarbonyl group, or a group having an acid decomposable group,
two of Ra1 to Ra3 may combine together to form a ring,
X1 represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014,
n represents an integer of 1 or 2,
1 and n2 each represents an integer of from 0 to 3, with proviso that (n, +n2) represents an integer of from 1 to 6, and
n3 represents an integer of from 0 to 3.
12. A polymerizable compound represented by any one of the following general formulae (Ib\u2032), (Ib\u2033), (IIb\u2032-1), (IIb\u2033-1), (IIIb\u2032-1) and (IIIb\u2033-1):
wherein
Rb1 represents a hydrogen atom, an alkyl group, or \u2014CH2\u2014O\u2014Rb2a, wherein Rb2a represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or a group having a lactone structure,
Rc represents a single bond or a divalent connecting group,
Ra1 and Ra2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an acyl group, or an acid decomposable group,
Ra1 and Ra2 may combine together to form a ring,
X1 represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014CH2O\u2014, \u2014O\u2014, \u2014S\u2014, or \u2014CH2S\u2014,
Y2 and Y3 each independently represents \u2014CH2\u2014, \u2014CH2CH2\u2014, \u2014O\u2014, or \u2014S\u2014,
Rb2, Rb3, and Rb4 each independently represents a hydrogen atom, an alkyl group, a hydroxyl group, a carboxyl group, or an alkoxycarbonyl group, and
n4 represents 0 or 1.
13. A method for forming a pattern, which comprises: forming a film from the photosensitive composition according to claim 1; exposing the film; and then developing the exposed film.

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. An unobtrusive system for monitoring the physiological condition of a target user of a vehicle comprising:
a wearable device affixed to the target user;
a measurement subsystem releasably coupled to the wearable device configured to measure a concentration of at least one analyte in the blood of the target user at one or more time increments;
a proximity sensor configured to detect the location of the wearable device; and
a vehicle control subsystem responsive to the proximity sensor and the measurement subsystem configured to determine if the wearable device is proximate a predetermined location in the vehicle and configured to determine if the measured concentration of the at least one analyte exceeds a predetermined threshold concentration level, and based on such a determination, initiate one or more predetermined actions.
2. The system of claim 1 in which the at least one analyte includes an analyte chosen from the group consisting of: alcohol, drugs, glucose, proteins, enzymes, hormones, glucose ethanol, insulin, water, carbon dioxide, blood oxygen, cholesterol, bilirubin, ketones, fatty acids, lipoproteins, albumin, urea, creatinine, white blood cells, red blood cells, hemoglobin, oxygenated hemoglobin, carboxyhemoglobin, organic molecules, inorganic molecules, pharmaceuticals, narcotics, tetrahydrocannabinol, cytochrome, various proteins and chromophores, microcalcifications, electrolytes, sodium, potassium, chloride, bicarbonate, and hormones.
3. The system of claim 1 in which the measurement subsystem is configured as an infrared spectrometer.
4. The system of claim 3 in which the infrared spectrometer includes one or more processors and a power supply located in the measurement subsystem and one or more processors, a light source, and a photodetector located in the wearable device.
5. The system of claim 4 in which the light source emits light at a predetermined wavelength into the subcutaneous layer of the skin of the target user and the photodetector detects the wavelength of the reflected light emitted the subcutaneous layer of the skin of the target user.
6. The system of claim 5 in which the measurement subsystem determines a change in the wavelength of the light emitted by the light source and the light detected by the photodetector to determine the concentration of the at least one analyte in the blood of the target user.
7. The system of claim 1 in which the measurement subsystem is uniquely matched to the wearable device.
8. The system of claim 7 in which the measurement subsystem includes a unique RF ID tag.
9. The system of claim 8 in which the wearable device includes a unique RF ID tag.
10. The system of claim 9 in which the measurement subsystem is configured to transmit physiological data of the measured concentration of the at least one analyte in the blood of the target user to the vehicle control subsystem when the RF ID tag of the measurement subsystem uniquely matches the RF ID tag of the wearable device.
11. The system of claim 9 in which the wearable device includes a processor configured to determine the identity of the RF ID tag of the wearable device.
12. The system of claim 11 in which the measurement subsystem includes a processor configured to determine if the identity of RF ID tag located in the measurement subsystem and if the RF ID tag of the measurement subsystem uniquely matches the RF ID tag of the wearable device.
13. The system of claim 11 in which the vehicle control subsystem includes one or more processors, one or more transmitters and one or more receivers.
14. The system of claim 13 further including a power supply coupled to the vehicle control system.
15. The system of claim 11 in which the wearable device includes one or more processors and one or more transmitters.
16. The system of claim 1 in which the wearable device includes a tamper proof bracket.
17. The system of claim 1 in which the wearable device includes a tamper proof anklet.
18. The system of claim 1 in which the wearable deice is coupled to the measurement subsystem by one or more electrical contacts.
19. The system of claim 4 in which the measurement subsystem includes one or more contacts for connecting to a power source for recharging the power supply.
20. The system of claim 4 further including one or more gaskets disposed between the measurement subsystem and the wearable device configured to adjust the distance between the measurement subsystem and the wearable device and minimize extraneous light.
21. The system of claim 1 in which the proximity sensor includes a DC pulse magnetic resonator configured to detect the distance and spatial orientation of a magnetic sensor located in the wearable device.
22. The system of claim 21 in which the proximity sensor is located in the vehicle.
23. The system of claim 21 in which the proximity sensor is located proximate the steering column of the vehicle.
24. The system of claim 21 in which the vehicle control system, responsive to signals from the proximity sensor, defines the predetermined location in the vehicle.
25. The system of claim 24 in which the vehicle control system is configured to determine if the wearable device is proximate the predetermined location in the vehicle.
26. The system of claim 25 in which the predetermined location is the area proximate the driver’s area of the vehicle.
27. The system of claim 26 in which the proximity sensor communicates to the vehicle control subsystem by a direct connection.
28. The system of claim 27 in which the proximity sensor communicates to the vehicle control system wirelessly.
29. The system of claim 1 in which the one or more time increments include a first time the target user starts the vehicle and thereafter at random andor predetermined time increments.
30. The system of claim 1 in which the one or more predetermined actions include an action chosen from the group consisting of: not allowing the vehicle to start, speed governing of the vehicle, a global positioning system response to law enforcement personnel as to the location of the vehicle, emitting light from the vehicle, and emitting sound from the vehicle.
31. The system of claim 1 in which the predetermined threshold concentration level includes about 0.08% alcohol in the blood of the target user, andor a measurable amount of illegal drugs in the blood of the target user andor a change in protein-c levels in the blood of the target user that may be indicative of a heart attack in the blood of the target user andor an unsafe blood glucose level in the blood of the target user.
32. An unobtrusive method for monitoring the physiological condition of a target user of a vehicle comprising:
affixing a wearable device to a target user;
measuring the concentration of at least one analyte in the blood of a target user in the vehicle one or more time increments;
determining if the wearable device is proximate a predetermined location in the vehicle; and
determining if the measured concentration of at least one analyte exceeds a predetermined threshold concentration level and based on such a determination, initiate one or more predetermined actions.
33. The method of claim 32 in which the at least one analyte includes an analyte chosen from the group consisting of: alcohol, drugs, glucose, proteins, enzymes, hormones, glucose ethanol, insulin, water, carbon dioxide, blood oxygen, cholesterol, bilirubin, ketones, fatty acids, lipoproteins, albumin, urea, creatinine, white blood cells, red blood cells, hemoglobin, oxygenated hemoglobin, carboxyhemoglobin, organic molecules, inorganic molecules, pharmaceuticals, narcotics, tetrahydrocannabinol, cytochrome, various proteins and chromophores, microcalcifications, electrolytes, sodium, potassium, chloride, bicarbonate, and hormones.
34. The method of claim 32 further including the step of emitting light at a predetermined wavelength into the subcutaneous layer of the skin of a target user and detecting the wavelength of the light emitted from the subcutaneous layer of the skin of the target user.
35. The method of claim 34 further including the step of determining a change in the wavelength of the light emitted into the subcutaneous layer of the skin of the target user, and the light emitted out of the subcutaneous layer of the skin of the target user to determine the concentration of the at least one analyte in the blood of the target user.
36. The method of claim 32 further including the step of determining if the wearable device is uniquely matched to the measurement subsystem.
37. The method of claim 32 in which the one or more actions include an action chosen from the group consisting of: not allowing the vehicle to start, speed governing of the vehicle, a global positioning system response to law enforcement personnel as to the location of the vehicle, emitting light from the vehicle, and emitting sound from the vehicle.
38. The method of claim 32 in which the predetermined threshold concentration level includes about 0.08% alcohol in the blood of the target user andor a measurable amount of illegal drugs in the blood of the target user andor a change in protein-c levels that may be indicative of a heart attack in the blood of the target user andor an unsafe blood glucose level in the blood of the target user.

1. In a non-volatile capacitor-less 1T DRAM having:
a semiconductor substrate of a first conducting type with a surface;
a first region of a second conductivity type in said substrate on said surface;
a second region of said second conductivity type in said substrate on said surface, spaced apart from said first region;
a body region of said first conductivity type in said substrate between said first region and said second region, said body region bound by said surface, one or more insulating regions and said first and second regions; wherein the improvement comprising:
a floating gate insulated from said surface and positioned between said first region and said second region; and
a control gate capacitively coupled to said floating gate.
2. The DRAM of claim 1 wherein said floating gate is insulated from a first portion of said surface of said body region between said first region and said second region; and
wherein said control gate is positioned adjacent to the floating gate and is insulated from a second portion of said surface of said body region between said first region and said second region, and is capacitively coupled to said floating gate.
3. The DRAM of claim 1 wherein said floating gate is insulated from said surface of said body region and is positioned over the entire surface between said first region and said second region; and
wherein said control gate is insulated from said floating gate and is positioned over said floating gate.
4. The DRAM of claim 2 wherein said floating gate further having a tip near an end adjacent to the control gate.
5. A method of operating a non-volatile capacitor-less 1T DRAM cell having a semiconductor substrate of a first conducting type with a surface; a first region of a second conductivity type in said substrate on said surface; a second region of said second conductivity type in said substrate, spaced apart from said first region; a body region of said first conductivity type in said substrate between said first region and said second region, said body region bound by said surface, one or more insulating regions and said first and second regions; a floating gate insulated from said surface and positioned between said first region and said second region; and a control gate capacitively coupled to said floating gate; wherein said method comprising:
operating said DRAM cell by storing data in said body region; and
storing said data in said body region to said floating gate upon detection of a loss in power.
6. The method of claim 5 further comprising:
restoring the data stored in the floating gate into the body region, upon application of power to said DRAM.
7. The method of claim 5 wherein said floating gate is insulated from a first portion of said surface of said body region between said first region and said second region, and is closer to said second region than to said first region; and wherein said control gate is positioned adjacent to the floating gate and is insulated from a second portion of said surface of said body region between said first region and said second region, and is capacitively coupled to said floating gate, and is closer to said first region than to said second region.
8. The method of claim 7 wherein said storing step comprises
applying a first negative voltage to the body of the substrate;
applying a first voltage to said first region;
applying a second voltage to said second region, said second voltage more positive than said first voltage; and
applying a third voltage to said control gate, said third voltage more positive than said first voltage, wherein said second voltage and third voltage are sufficient to cause electrons to be injected onto the floating gate if holes are stored in the body region.
9. The method of claim 6 wherein said floating gate is insulated from a first portion of said surface of said body region between said first region and said second region, and is closer to said second region than to said first region; and wherein said control gate is positioned adjacent to the floating gate and is insulated from a second portion of said surface of said body region between said first region and said second region, and is capacitively coupled to said floating gate, and is closer to said first region than to said second region.
10. The method of claim 9, wherein said restoring step comprises:
applying a negative voltage to the body;
applying a first voltage to said first region;
applying a second voltage to said second region, said second voltage more positive than said first voltage; and
applying a third voltage to said control gate, wherein said third voltage is a negative voltage.
11. The method of claim 8, further comprising the step of:
initializing said DRAM prior to said operating step, where in said initializing step comprises:
applying a positive voltage to said control gate;
applying a second negative voltage to the body of said substrate.
12. The method of claim 5 wherein said floating gate is insulated from said surface of said body region and is positioned over the entire surface between said first region and said second region; and wherein said control gate is insulated from said floating gate and is positioned over said floating gate.
13. The methods of claim 12 wherein said storing step comprises:
applying a first positive voltage to the control gate; and
applying a first negative voltage to the body of the substrate.
14. The method of claim 6 wherein said floating gate is insulated from said surface of said body region and is positioned over the entire surface between said first region and said second region; and wherein said control gate is insulated from said floating gate and is positioned over said floating gate.
15. The method of claim 14 wherein said restoring step comprises:
applying a second negative voltage said control gate;
applying a third negative voltage to the body of said substrate, wherein said third negative voltage is more negative than said second negative voltage; and
applying a second positive voltage to said second region.
16. The method of claim 13, further comprising the step of:
initializing said DRAM prior to said operating step, said initializing step comprising:
applying a first negative voltage to said control gate;
applying a second negative voltage to the body of said substrate, wherein said first negative voltage is more negative than said second negative voltage.

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 for estimating contents of a cache by a computer comprising a processor, comprising:
determining, by the processor, table descriptors referenced by a query, wherein each table descriptor identifies one or more tables in a database system, wherein the determining table descriptors referenced by the query comprises:
providing a central lookup table comprising a page count entry corresponding to a table descriptor for each table in the database system;
using a single scan of each page header stored in the cache, determining, by the processor, if a table descriptor from each page header matches any of the table descriptors referenced by the query;
for each table descriptor from the page headers stored in the cache determined to match any of the table descriptors referenced by the query, increasing, by the processor, a page count value corresponding to the matching table descriptor referenced by the querying, wherein the page count value corresponding to the table descriptor for each table in the database is set to an initial value in an intermediate memory, wherein the increasing the page count value corresponding to the matching table descriptor referenced by the query further comprises: updating the corresponding page count value in the central look-up table with the page count values corresponding to the matching table descriptor referenced by the query;
estimating, by the processor, the contents of the cache using the page count values for each table descriptor referenced by the query; and
calculating, by the processor, a cost of a query execution plan for the query using the estimated contents of the cache.
2. The method of claim 1, wherein the determining the table descriptor referenced by the query comprises:
setting a page count for each referenced table descriptor to an initial value.
3. The method of claim 1, wherein the estimating the contents of the cache using the page count values for each table descriptor referenced by the query comprises: retrieving the page count values corresponding to the table descriptors referenced by the query from the central lookup table.
4. The method of claim 1, wherein the database system comprises a plurality of threads, wherein the increasing the page count value corresponding to the matching table descriptor referenced by the query comprises:
providing a hash table for each of the plurality of threads, each hash table comprising a page count entry corresponding to a table descriptor for each table in the database system, each hash table maintained independently by the owning thread;
for each thread of the plurality of threads:
when the thread copies a page of a first table in the database system into the cache, increasing the page count value corresponding to the first table’s table descriptor in the hash table of the thread; and
when the thread removes a page of a second table in the database system from the cache, decreasing the page count value corresponding to the second table’s table descriptor in the hash table of the thread.
5. The method of claim 4,
wherein the estimating the contents of the cache using the page count value for each table descriptor referenced by the query comprises:
retrieving the page count values corresponding to each table descriptor referenced by the query from the hash tables of each thread; and
determining a sum of the retrieved page count values for each table descriptor referenced by the query.
6. A method for estimating contents of a cache by a computer comprising a processor, comprising:
determining table descriptors referenced by a query for one or more tables in a database system, wherein the database system comprises a plurality of threads;
determining a page count value for each referenced table descriptor using a single scan of table descriptors in page headers stored in a cache, comprising:
providing a hash table for each of the plurality of threads, each hash table comprising a page count entry corresponding to a table descriptor for each table in the database system, each hash table maintained independently by the owning thread;
for each thread of the plurality of threads:
when the thread copies a page of a first table in the database system into the cache, increasing the page count value corresponding to the first table’s table descriptor in the hash table of the thread;
when the thread removes a page of a second table in the database system from the cache, decreasing the page count value corresponding to the second table’s table descriptor in the hash table of the thread;
providing a global hash table comprising a global page count entry corresponding to a table descriptor for each table in the database system, wherein for each hash table of the plurality of threads:
determining if the hash table corresponds to a dead thread;
in response to determining that the hash table corresponds to a dead thread, obtaining the page count values in the hash table of the dead thread;
increasing the corresponding global page count values by the obtained page count values; and
removing the hash table of the dead thread from memory; and
estimating the contents of the cache using the determined page count values, comprising:
retrieving the page count values corresponding to each referenced table descriptor from the hash tables of each thread; and
determining a sum of the retrieved page count values for each referenced table descriptor.
7. The method of claim 6, wherein for each referenced table descriptor in the query, the estimating of the contents of the cache using the determine page count values comprises:
retrieving the page count values corresponding to the referenced table descriptor from the hash table of each thread and from the global hash table; and
determining the sum of the retrieved page count values.
8. The method of claim 4, further comprising:
providing a global hash table comprising a global page count entry corresponding to the table descriptor for each table in the database system;
retrieving the page count values corresponding to each table descriptor from the hash tables of each thread;
determining a sum of the retrieved page count values for each table descriptor;
increasing the corresponding global page count value by the determined sum of each table descriptor; and
setting the page count values in the hash tables of each thread to an initial value.
9. A computer readable memory device comprising a computer program product for estimating contents of a cache, the computer program product executed by a processor comprising:
a computer readable memory having computer readable program code embodied therewith, the computer readable program code configured to:
determine table descriptors referenced by a query, wherein each table descriptor identifies one or more tables in a database system;
set a page count value for each referenced table descriptor to an initial value;
provide a central lookup table comprising a page count entry corresponding to a table descriptor for each table in the database system, wherein the page count value corresponding to the table descriptor for each table in the database system is set to the initial value in an intermediate memory, wherein the computer readable program code configured to increase the page count value corresponding to the matching table descriptor referenced by the query is further configured to:
update the corresponding page count value in the central look-up table with the page count values corresponding to the matching table descriptor referenced by the query;
using a single scan of each page header stored in the cache, determine if a table descriptor from each page header matches any of the table descriptors referenced by the query;
for each table descriptor from the page headers stored in the cache determined to match any of the table descriptors referenced by the query, increase a page count value corresponding to the matching table descriptor referenced by the query estimate the contents of the cache using the page count value for each table descriptor referenced by the query; and
calculate a cost of a query execution plan for the query using the estimated contents of the cache.
10. The computer readable program product of claim 9, wherein the database system comprises a plurality of threads, wherein the computer readable program code configured to increase the page count value corresponding to the matching table descriptor referenced by the query is further configured to:
provide a hash table for each of the plurality of threads, each hash table comprising a page count entry corresponding to a table descriptor for each table in the database system, each hash table maintained independently by the owning thread;
for each thread of the plurality of threads:
when the thread copies a page of a first table in the database system into the cache, increase the page count value corresponding to the first table’s table descriptor in the hash table of the thread; and
when the thread removes a page of a second table in the database system from the cache, decrease the page count value corresponding to the second table’s table descriptor in the hash table of the thread.
11. The computer program product of claim 10,
wherein the computer readable program code configured to estimate the contents of the cache using the page count value for each table descriptor referenced by the query is further configured to:
retrieve the page count values corresponding to each table descriptor referenced by the query from the hash tables of each thread; and
determine a sum of the retrieved page count values for each table descriptor referenced by the query.
12. A system, comprising:
database tables, each database table comprising a plurality of pages; and a computer operatively coupled to the database tables, the computer comprising;
a processor;
a cache comprising copies of one or more of the plurality of pages; and
a computer readable memory operatively coupled to the processor and the cache, the computer readable memory having computer readable program code embodied therewith, the computer readable program code configured to:
determine table descriptors referenced by a query, wherein each table descriptor identifies one or more tables of the database tables;
set a page count value for each referenced table descriptor to an initial value:
provide a central lookup table comprising a page count entry corresponding to a table descriptor for each table in the database system, wherein the page count value corresponding to the table descriptor for each table in the database system is set to the initial value in an intermediate memory, wherein the computer readable program code configured to increase the page count value corresponding to the matching table descriptor referenced by the query is further configured to:
update the corresponding page count value in the central look-up table with the page count value corresponding to the matching table descriptor referenced by the query;
using a single scan of each page header stored in the cache, determine if a table descriptor from each page header matches any of the table descriptors referenced by the query;
for each table descriptor from the page headers stored in the cache determined to match any of the table descriptors referenced by the query, increase a page count value corresponding to the matching table descriptor referenced by the query;
estimate contents of the cache using the page count value for each table descriptor referenced by the query; and
calculate a cost of a query execution plan for the query using the estimated contents of the cache.
13. The system of claim 12, further comprising a plurality of threads, wherein the computer readable program code configured to increase the page count value corresponding to the matching table descriptor referenced by the query is further configured to:
provide a hash table for each of the plurality of threads, each hash table comprising a page count entry corresponding to a table descriptor for each table in the database system, each hash table maintained independently by the owning thread;
for each thread of the plurality of threads:
when the thread copies a page of a first table in the database system into the cache, increase the page count value corresponding to the first table’s table descriptor in the hash table of the thread; and
when the thread removes a page of a second table in the database system from the cache, decrease the page count value corresponding to the second table’s table descriptor in the hash table of the thread,

wherein the computer readable program code configured to determine the referenced table descriptors for the one or more tables in the database system is further configured to: determine table descriptors referenced by a query;
wherein for each referenced table descriptor, the computer readable program code configured to estimate the contents of the cache using the determined page count values is further configured to:
retrieve the page count values corresponding to each referenced table descriptor from the hash tables of each thread; and
determine a sum of the retrieved page count values for each referenced table descriptor.
14. A computer readable memory device comprising a computer program product for estimating contents of a cache, the computer program product executed by a processor comprising:
a computer readable memory having computer readable program code embodied therewith, the computer readable program code configured to:
determine table descriptors referenced by a query for one or more tables in a database system, wherein the database system comprises a plurality of threads;
determine a page count value for each referenced table descriptor using a single scan of table descriptors in page headers stored in a cache, configured to:
provide a hash table for each of the plurality of threads, each hash table comprising a page count entry corresponding to a table descriptor for each table in the database system, each hash table maintained independently by the owning thread;
for each thread of the plurality of threads:
when the thread copies a page of a first table in the database system into the cache, increase the page count value corresponding to the first table’s table descriptor in the hash table of the thread;
when the thread removes a page of a second table in the database system from the cache, decrease the page count value corresponding to the second table’s table descriptor in the hash table of the thread;
provide a global hash table comprising a global page count entry corresponding to a table descriptor for each table in the database system, wherein for each hash table of the plurality of threads:
determine if the hash table corresponds to a dead thread;
in response to determining that the hash table corresponds to a dead thread, obtain the page count values in the hash table of the dead thread;
increase the corresponding global page count values by the obtained page count values; and
remove the hash table of the dead thread from memory; and
estimate the contents of the cache using the determined page count values, comprising:
retrieve the page count values corresponding to each referenced table descriptor from the hash tables of each thread; and
determine a sum of the retrieved page count values for each referenced table descriptor.
15. A system, comprising:
database tables, each database table comprising a plurality of pages; and
a computer operatively coupled to the database tables, the computer comprising:
a processor;
a cache comprising copies of one or more of the plurality of pages; and
a computer readable memory operatively coupled to the processor and the cache, the computer readable memory having computer readable program code embodied therewith, the computer readable program code configured to:
determine table descriptors referenced by a query for one or more tables in a database system, wherein the database system comprises a plurality of threads;
determine a page count value for each referenced table descriptor using a single scan of table descriptors in page headers stored in a cache, configured to:
provide a hash table for each of the plurality of threads, each hash table comprising a page count entry corresponding to a table descriptor for each table in the database system, each hash table maintained independently by the owning thread;
for each thread of the plurality of threads:
\u2003when the thread copies a page of a first table in the database system into the cache, increase the page count value corresponding to the first table’s table descriptor in the hash table of the thread;
\u2003when the thread removes a page of a second table in the database system from the cache, decrease the page count value corresponding to the second table’s table descriptor in the hash table of the thread;
provide a global hash table comprising a global page count entry corresponding to a table descriptor for each table in the database system,
wherein for each hash table of the plurality of threads:
\u2003determine if the hash table corresponds to a dead thread;
\u2003in response to determining that the hash table corresponds to a dead thread, obtain the page count values in the hash table of the dead thread;
\u2003increase the corresponding global page count values by the obtained page count values; and
\u2003remove the hash table of the dead thread from memory; and

estimate the contents of the cache using the determined page count values, comprising:
retrieve the page count values corresponding to each referenced table descriptor from the hash tables of each thread; and
determine a sum of the retrieved page count values for each referenced table descriptor.