[IGNITE-5961] Align pages in LFS partition files to pageSize

• Type: Improvement
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.1
• Fix Version/s: 2.3
• Component/s: persistence
• Assignee: Ivan Rakov
• Reporter: Ivan Rakov
• Created: 07/Aug/17 14:18
• Updated: 28/Aug/17 16:38
• Resolved: 10/Aug/17 10:49

Description

We store 17 bytes of header at the start of every partition file:

    /** Allocated field offset. */
    static final int HEADER_SIZE = 8/*SIGNATURE*/ + 4/*VERSION*/ + 1/*type*/ + 4/*page size*/;

Even if pageSize is equal to OS page cache size and equal to SSD disk page size (which is best scenario), we generate two dirty pages instead of one. This is suboptimal and can be a bottleneck of checkpoint write speed.

Issue Links

• relates to: IGNITE-6204 Backport optimizations of checkpointing algorithm into 2.2