Diagnostics and Troubleshooting

This document gives brief references to diagnostics and troubleshooting interfaces available in the library.

A small collection of print routines is available which can be used to examine key data strucures, such as the SplinterDB trunk pages, BTree pages, space-allocation maps and so on.

• trunk_print_super_block Print contents of SplinterDB super block

• trunk_print Print contents of a Trunk node (page)

• trunk_print_subtree Print contents of all sub-trees under a Trunk node (page)

• trunk_print_space_use Print space usage by level across all trunk nodes

• trunk_print_memtable Print contents of all Memtables in Splinter. Drills-down to printing BTrees under Memtables

• btree_print_tree, btree_print_node, btree_print_locked_node Print BTree nodes, and recurse down to sub-tree nodes.

• rc_allocator_print_allocated Print the space allocation maps and lists of extents / pages allocated.

• rc_allocator_print_stats Prints basic statistics about the allocator state.

A small unit test to exercise these print diagnostics can be found here, splinter_test.c:test_splinter_print_diags.

A useful way to learn about SplinterDB internal structures is to run this test case: $ bin/unit/splinter_test test_splinter_print_diags

This test case creates a small SplinterDB instance, and loads a large set of rows, enough to create several pages in the trunk.

Examine the outputs generated in /tmp/unit_test.stdout by this test case to get a quick view of the internal structures.