1. A method of routing workload data to a plurality of processing sites, comprising:
defining, using a processor, a maximum replication latency threshold and a reset threshold;
providing an update workload to a first of the plurality of processing sites;
providing the update workload from the first of the plurality of processing sites to another of the plurality of processing sites;
estimating a replication latency of the workload for the plurality of sites using a difference in time between completion of a transaction on the update workload at a first of the plurality of processing sites and a completion of a replication process of the transaction at the other of the plurality of processing sites;
switching to an acute replication latency state for the plurality of processing sites when the estimated replication latency of the workload rises above the defined maximum replication latency threshold, wherein a query workload is provided to only the first of the processing sites in the acute replication latency state; and
switching out of the acute replication latency state when the estimated replication latency falls below the defined reset threshold.
2. The method of claim 1, wherein the reset threshold is less than the maximum replication latency threshold.
3. The method of claim 1, wherein switching out of the acute replication latency state further comprises switching to a normal replication latency state of the plurality of sites.
4. The method of claim 3, wherein the query workload is distributed to each of the processing sites in the normal replication latency state.
5. The method of claim 3, further comprising defining at least one other replication latency state over a range of replication latency values between the normal replication latency state and the acute replication latency state, wherein the at least one other replication latency state favors use of a single-site distribution configuration.
6. The method of claim 5, further comprising switching from the normal replication latency state to the at least one other replication latency state when the estimated replication latency lies within the selected range of replication latency values defining the at least one other replication latency state.
7. The method of claim 1, further comprising estimating the replication latency by obtaining an average of replication latencies for the plurality of processing sites over a selected time interval.
8. A data processing system, comprising:
a first processing site configured to perform a transaction on an update workload;
a second processing site configured to perform a replication process of the transaction at the first processing site;
a workload distributor for distributing a query workload to one or more of the first processing site and the processing second site;
a transaction replay program configured to send a copy of update workload from the first site to the second site; and
a processor configured to:
define a maximum replication latency threshold and a reset threshold for the system,
estimate a replication latency of a workload in the system from a difference in time between completion of the transaction at the first processing site and a completion of the replication process at the second processing site, and
switch the system to an acute replication latency state when the estimated replication latency rises above the maximum replication latency threshold and switch out of the acute replication latency state when the estimated replication latency falls below the reset threshold, wherein the query workload is distributed to only the first processing site when the system is in the acute replication latency state.
9. The system of claim 8, wherein the reset threshold is less than the maximum replication latency threshold.
10. The system of claim 8, wherein the processor is further configured to switch out of the acute replication latency state directly into a normal replication latency state of the plurality of sites when the estimated replication latency falls below the reset threshold.
11. The system of claim 8, wherein query workload is distributed to the first processing site and the second processing site when the system is in the normal replication latency state.
12. The system of claim 10, wherein the processor is further configured to define at least one other replication latency state over a range of replication latency values between the normal replication latency state and the acute replication latency state, wherein the at least one other replication latency state favors use of a single-site distribution configuration.
13. The system of claim 12, wherein the processor is further configured to switch from the normal replication latency state to the at least one other replication latency state when the estimated replication latency lies within the defined range.
14. The system of claim 13, wherein the processor is further configured to estimate the replication latency as an average of replication latencies of the workload over a selected time interval.
15. A method of operating a system of independent processing sites, comprising:
defining, using a processor, a maximum replication latency threshold and a reset threshold of the system;
providing an update workload to a first of the plurality of processing sites;
providing the update workload from the first of the plurality of processing sites to another of the plurality of processing sites;
estimating a replication latency of a workload in the system as a difference in time between completion of a transaction at a first of the processing sites and a completion of a replication process of the transaction at another of the plurality of sites;
switching the system to a first replication latency state when the estimated replication latency rises above the maximum replication latency threshold, wherein a query workload is provided to only the first of the processing sites in the acute replication latency state; and
switching the system out of the first replication latency state to a second replication latency state when the estimated replication latency falls below the reset threshold.
16. The method of claim 15, wherein the reset threshold is less than the maximum replication latency threshold.
17. The method of claim 15, wherein the first replication latency state includes an acute replication latency state and the second replication latency state includes a normal replication latency state.
18. The method of claim 17, further comprising defining at least one replication latency state over a selected range of replication latency values between the normal replication latency state and the acute replication latency state.
19. The method of claim 18, further comprising switching from the normal replication latency state to the at least one other replication latency state when the estimated replication latency lies within the selected range of replication latency values.
20. The method of claim 15, wherein estimating the replication latency of the workload further comprising obtaining an average of replication latencies for the workload over a selected time interval.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A method of making a modified particle comprising a particle having attached a group having the formula:
19
wherein Ar represents an aromatic group; R1 represents a bond, an arylene group, an alkylene group,
20
wherein R4 is an alkyl or alkylene group or an aryl or arylene group; R2 and R3, which can be the same or different, represent hydrogen, an alkyl group, an aryl group, OR5, NHR5, NR5R5, or SR5, wherein R5, which is the same or different, represents an alkyl group or an aryl group; and SFR represents a stable free radical, wherein said method comprises reacting a) a particle having attached an aromatic group with a group containing an abstractable proton and which leaves behind a carbon-centered radical when the proton is abstracted with b) a reactive free radical source and c) a stable free radical source.
2. The method of claim 1, wherein said SFR has the formula:
21
wherein R6 and R7, which can be the same or different, represent a substituted or unsubstituted alkyl or cycloalkyl group; and Ar2 represents an aromatic group.
3. The method of claim 1, wherein said particle is a carbon product, a metal oxide, a metal hydroxide, or mixtures thereof.
4. The method of claim 1, wherein said particle is graphite, vitreous carbon, activated charcoal, carbon fiber, activated carbon, or mixtures thereof.
5. The method of claim 1, wherein said particle is carbon black.
6. The method of claim 1, wherein said particle is an aggregate comprising a silicon-containing species phase and a carbon phase.
7. The method of claim 1, wherein said particle is an aggregate comprising a metal-containing species phase and a carbon phase.
8. The method of claim 1, wherein said stable free radical source is 2,2,5,5-tetramethyl-1-pyrrolidinyloxy, 2,2,6,6-tetramethyl-1-piperindinyloxy, or derivatives thereof.
9. The method of claim 1, wherein said reactive free radical source comprises organic peroxides or azo initiators.
10. The method of claim 1, wherein said reactive free radical source is a benzoyl peroxide or a t-butyl peroxide.
11. The method of claim 1, wherein said reactive free radical source comprises t-butyl peroxide.
12. The method of claim 1, wherein said group which contains an abstractable proton and is capable of leaving behind a carbon-centered radical upon proton abstraction comprises an alkyl group or an alkene group with a hydrogen atom in the alpha position to the olefinic bond.
13. The method of claim 1, wherein said group which contains an abstractable proton and is capable of leaving behind a carbon-centered radical comprises a C1-C20 alkyl group.
14. The method of claim 13, wherein said C1-C20 alkyl group is a methyl, ethyl, propyl, butyl, or hexyl group.
15. The method of claim 13, wherein said C1-C20 alkyl group is an ethyl group.
16. The method of claim 1, wherein said aromatic group is first attached onto the particle and then said group containing an abstractable proton which leaves behind a carbon-centered radical upon proton abstraction is then attached onto the aromatic group.
17. The method of claim 1, wherein an aromatic group having attached thereto a group containing an abstractable proton which is capable of leaving behind a carbon-centered radical is first formed and then attached onto the particle wherein said aromatic group is directly attached to the particle.
18. The method of claim 1, further comprising reacting said modified particle with a polymerizable monomer to form a modified particle comprising a particle having attached a group having the formula:
22
wherein Ar represents an aromatic group; R1 represents a bond, an arylene group, an alkylene group,
23
wherein R4 is an alkyl or alkylene group or an aryl or arylene group; R2 and R3, which can be the same or different, represent hydrogen, an alkyl group, an aryl group, OR5, NHR5, NR5R5, or SR5, wherein R5, which is the same or different, represents an alkyl group or an aryl group; SFR represents a stable free radical; and X represents a polymer formed from at least one polymerizable monomer.
19. The method of claim 18, wherein said polymerizable monomer is a vinyl or diene containing monomer.
20. The method of claim 18, wherein said particle is a carbon product, a metal oxide, a metal hydroxide, or mixtures thereof.
21. The method of claim 18, wherein said particle is graphite, carbon black, vitreous carbon, activated charcoal, carbon fiber, activated carbon, or mixtures thereof.
22. The method of claim 18, wherein said particle is an aggregate comprising a silicon-containing species phase and a carbon phase.
23. The method of claim 18, wherein said particle is an aggregate comprising a metal-containing species phase and a carbon phase.
24. The method of claim 18, wherein said particle is carbon black.
25. The method of claim 18, wherein said SFR is 2,2,5,5-tetramethyl-1-pyrrolidinyloxy, 2,2,6,6tetramethyl-1-piperindinyloxy, or derivatives thereof.
26. The method of claim 18 further comprising terminating the -SFR group.
27. The method of claim 26, wherein said termination is accomplished by replacing the -SFR group with a proton, by disproportionation, or by replacement with a chemical group other than the -SFR group.
28. The method of claim 27, wherein said chemical group is a hydroxy group or halide group.