[DiskBBQ] save same vector operations when performing centroid filtering

[iverase]

It saves some vector operations by:

• Checking if there is any non filtered centroid when scoring children centroids
• No scoring the parents if we are going to collect all centroids

[elasticsearchmachine]

Pinging @elastic/es-search-relevance (Team:Search Relevance)

[iverase]

I need this on test to increase the visit ratio

[benwtrent]

This should improve things nicely! Do you have any benchmarks?

[iverase]

Benchmarks show a slight improvement:

Before:

index_name       index_type  visit_percentage(%)  latency(ms)  net_cpu_time(ms)  avg_cpu_count     QPS  recall    visited  filter_selectivity
---------------  ----------  -------------------  -----------  ----------------  -------------  ------  ------  ---------  ------------------ 
wiki1024en.docs         ivf                 0.00         5.44              0.00           0.00  183.82    0.97    4110.61              0.0100
wiki1024en.docs         ivf                 0.00         5.75              0.00           0.00  173.91    0.97    2515.54              0.0050
wiki1024en.docs         ivf                 0.00         6.85              0.00           0.00  145.99    0.97    1932.36              0.0025
wiki1024en.docs         ivf                 0.00         5.48              0.00           0.00  182.48    1.00    1500.43              0.0010
wiki1024en.docs         ivf                 0.00         1.82              0.00           0.00  549.45    1.00     496.00              0.0003

After:

index_name       index_type  visit_percentage(%)  latency(ms)  net_cpu_time(ms)  avg_cpu_count     QPS  recall    visited  filter_selectivity
---------------  ----------  -------------------  -----------  ----------------  -------------  ------  ------  ---------  ------------------ 
wiki1024en.docs         ivf                 0.00         5.49              0.00           0.00  182.15    0.97    4110.61              0.0100
wiki1024en.docs         ivf                 0.00         5.65              0.00           0.00  176.99    0.97    2515.54              0.0050
wiki1024en.docs         ivf                 0.00         5.75              0.00           0.00  173.91    0.97    1932.36              0.0025
wiki1024en.docs         ivf                 0.00         5.17              0.00           0.00  193.42    1.00    1500.43              0.0010
wiki1024en.docs         ivf                 0.00         1.56              0.00           0.00  641.03    1.00     496.00              0.0003