Background
The current implementation of Cps Path queries relies on regular expressions in the generated SQL queries.
TODO: Examples of CpsPathQuery to SQL query
The use of regex potentially results in full table scans, severely limiting performance, and causing query time duration to grow linearly with the database size (i.e. queries get slower as the DB gets bigger).
A new algorithm for queries is being proposed, avoiding regex, so that query duration is independent of database size.
Proposal
The new approach involves adding a column to the Fragment table, storing the xpath component.
Proof of Concept
A PoC was developed so that performance could be compared against existing Cps Path Query algorithms.
Performance Improvement
| Time (ms) for X devices | |||||||
| Case | Scenario | Query | Descendants | Branch | 50 | 500 | 1000 |
|---|---|---|---|---|---|---|---|
| 1a | Query 1 device from many, descendant cps path | //openroadm-device[@device-id="C201-7-1A-14"] | none | master | 64 | 539 | 1,451 |
| 1b | none | poc | 33 | 28 | 65 | ||
| 2a | //openroadm-device[@device-id="C201-7-1A-25"] | direct | master | 87 | 583 | 1,580 | |
| 2b | direct | poc | 34 | 35 | 70 | ||
| 3a | //openroadm-device[@device-id="C201-7-1A-36"] | all | master | 92 | 619 | 1,693 | |
| 3b | all | poc | 51 | 43 | 67 | ||
| 4a | Query 1 device from many, absolute cps path | /openroadm-devices/openroadm-device[@device-id="C201-7-1A-19"] | none | master | 97 | 881 | 2,383 |
| 4b | none | poc | 28 | 14 | 14 | ||
| 5a | /openroadm-devices/openroadm-device[@device-id="C201-7-1A-32"] | direct | master | 119 | 900 | 2,403 | |
| 5b | direct | poc | 31 | 17 | 16 | ||
| 6a | /openroadm-devices/openroadm-device[@device-id="C201-7-1A-46"] | all | master | 127 | 912 | 2,471 | |
| 6b | all | poc | 44 | 27 | 28 | ||
| 7a | Query many devices from many, descendant cps path | //openroadm-device[@ne-state="inservice"] | none | master | 72 | 606 | 1,547 |
| 7b | none | poc | 40 | 167 | 737 | ||
| 8a | //openroadm-device[@ne-state="inservice"] | direct | master | 560 | 11,552 | 41,652 | |
| 8b | direct | poc | 142 | 620 | 1,428 | ||
| 9a | //openroadm-device[@ne-state="inservice"] | all | master | 577 | 12,027 | 43,321 | |
| 9b | all | poc | 227 | 1,450 | 3,502 | ||
| 10a | Query many devices from many, absolute cps path | /openroadm-devices/openroadm-device[@status="success"] | none | master | 99 | 892 | 1,808 |
| 10b | none | poc | 29 | 44 | 107 | ||
| 11a | /openroadm-devices/openroadm-device[@status="success"] | direct | master | 404 | 11,900 | 42,422 | |
| 11b | direct | poc | 68 | 325 | 797 | ||
| 12a | /openroadm-devices/openroadm-device[@status="success"] | all | master | 482 | 11,937 | 42,581 | |
| 12b | all | poc | 238 | 1,298 | 3,048 | ||