[DOCS-224] State explicit formulas for index related stuff Created: 14/Jun/12  Updated: 30/Oct/23  Resolved: 27/Jul/16

Status: Closed
Project: Documentation
Component/s: manual
Affects Version/s: None
Fix Version/s: Server_Docs_20231030

Type: Improvement Priority: Minor - P4
Reporter: Richard Kreuter (Inactive) Assignee: Unassigned
Resolution: Won't Fix Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Duplicate
is duplicated by DOCS-859 limits document incorrect for size of... Closed
Related
is related to DOCS-206 Indexing Advice should be reviewed Closed
Participants:
Days since reply: 7 years, 29 weeks ago

 Description   

The docs ought to include formulas for calculating the sizes of various index-related things:

  • the sizes of compound index keys (this changed from v0 to v1 indexes)
  • the estimated size of an index based on the number and average size of index keys

Eliot says that v0 index keys are BSON objects with empty keys, so the key size should be 4 + <number of fields> + <sizes of fields> + 1. If all the fields are fixed size (e.g., numbers/booleans/ObjectIds/Dates/Timestamps), then all index keys should be the same size. For any variably sized scalar field (e.g., string/binary/etc.), the size of the field includes a 4-byte length and typically an extra byte (null byte for strings, subtype for binary.

Anyway, this is a start.



 Comments   
Comment by Emily Hall [ 27/Jul/16 ]

Closed for housekeeping on 7/27/2016 by Emily Hall.
If you require additional support, please open a new ticket for prioritization.
Thanks,
Emily

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