tree 3f2ecb59657ace07b54823fba38f489a0d2727b2
parent 2934899ca67829b4882e52a3264374477308201d
author Alan Woodward <romseygeek@apache.org> 1686308279 +0100
committer GitHub <noreply@github.com> 1686308279 +0100
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Better paging when random reads go backwards (#12357)

When reading data from outside the buffer, BufferedIndexInput always resets
its buffer to start at the new read position. If we are reading backwards (for example,
using an OffHeapFSTStore for a terms dictionary) then this can have the effect of
re-reading the same data over and over again.

This commit changes BufferedIndexInput to use paging when reading backwards,
so that if we ask for a byte that is before the current buffer, we read a block of data
of bufferSize that ends at the previous buffer start.

Fixes #12356