FCB takes a long time to retrieve an entry

[javankl]

Describe the bug

I am using a Nordic nrf52832 and storing sensor readings in a FCB in external spi nor flash. When the device reports a reading, it uses fcb_getnext() to step through the readings to find the requested reading based on a reading index saved with the reading in the FCB. Each time I try to retrieve a reading, the FCB needs to step through the flash area from the beginning. When I do this, it takes about 1ms to take a step in the FCB and read the entry from flash. After I've collected over a hundred readings, the FCB takes about 100ms to find the requested sample and about 6 seconds near 10k readings. This is far too long of a wait for my application. I've looked into if the flash chip is getting put into low power mode, but setting CONFIG_SPI_NOR_IDLE_IN_DPD to 'n' doesn't change anything, nor does it seem it would as I don't have any power management set up at the moment. My project won't always have to return the latest reading and any reading in the FCB could be requested, otherwise I would use fcb_offset_last_n().

To Reproduce

• Use fcb_append() to save a hundred entries with an incrementing index number to an FCB on an external spi flash chip
• Save k_uptime_get()
• Try to read the latest entry by looping through fcb_getnext() and flash_area_read() until the received entry index equals the requested index
• Output k_uptime_delta() with the original time as the reference

Expected behavior

I expect my fcb_getnext() and flash_area_read() to take on the level of microseconds, not milliseconds.

Impact

This is a showstopper as far as using FCB for my application.

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[ShahinHaque97-CT]

This issue has been resolved, Not a power related issue, User now is seeking to the record they wish to read, rather than starting reading from the first record