Support 'expected_num_objects' parameter when creating pool for pg folder splitting #2031
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…pre-create PG folders. Signed-off-by: Guang Yang (yguang@yahoo-inc.com)
| @@ -920,6 +937,7 @@ struct pg_pool_t { | |||
| bool has_write_tier() const { return write_tier >= 0; } | |||
| void clear_write_tier() { write_tier = -1; } | |||
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| uint64_t expected_num_objects; ///< pre-hash pg folders based on the value of this setting | |||
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I would not tie the field to the implementation detail in the comment.
Adding a field to pg_pool_t does require changes to the encode(), decode(), dump(), and generate_test_instances() fields in the struct, though. Normally that would be wrapped up in a single commit. See the last change as an example: 931ae6b
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Create a new pull request:
Here is the new pull request - #2043 Thanks all. |
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This patch adds a new parameter for pool creation named 'expected_num_objects', to give user a choice to specify the number of objects he/she would like to put into the pool. This information is used to pre-hash PG's namespace by creating a certain number of folders, so as to avoid run-time folder splitting which could saturate disk I/O.
Testing - test against various combinations of PG number and splittings.
Issue - as we add two new fields to coll_t struct, and given its encode/decode logic, when we bump up the version number, it could break old version software. This would request to upgrade all nodes before creating new pool.
Todo - doc the behavior.
Signed-off-by: Guang Yang (yguang@yahoo-inc.com)