Optimize the order of compressed chunk metadata columns

[akuzm]

Put global metadata columns first, segmentby next, orderby metadata before the compressed orderby columns. This matches the order in which they are likely to be accessed when reading from a compressed chunk.

This affects only the newly created compressed chunks, and the execution over either old or new chunks is not affected, because it does not depend on the particular attribute numbers.

In tsbench, this improves one query which accesses only an early column UserID of a wide table hits. Before this PR, the compressed slot would be deformed entirely, because the count metadata column was after all the compressed columns.
https://grafana.ops.savannah-dev.timescale.com/d/fasYic_4z/compare-akuzm?orgId=1&var-branch=All&var-run1=3273&var-run2=3275&var-threshold=0&var-use_historical_thresholds=true&var-threshold_expression=2.5%20%2A%20percentile_cont%280.90%29&var-exact_suite_version=false

Fixes #5766

Disable-check: force-changelog-file

[codecov]

Codecov Report

Attention: Patch coverage is 89.18919% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 81.53%. Comparing base (59f50f2) to head (9dfdbc0).
Report is 34 commits behind head on main.

Files	Patch %	Lines
tsl/src/nodes/decompress_chunk/exec.c	80.00%	0 Missing and 3 partials ⚠️
tsl/src/nodes/decompress_chunk/decompress_chunk.c	66.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6664      +/-   ##
==========================================
+ Coverage   80.06%   81.53%   +1.46%     
==========================================
  Files         190      191       +1     
  Lines       37181    36431     -750     
  Branches     9450     9461      +11     
==========================================
- Hits        29770    29705      -65     
+ Misses       2997     2962      -35     
+ Partials     4414     3764     -650     

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[antekresic]

🎉

[jnidzwetzki]

Is there a specific reason for not moving the segment_by columns (i.e., a, c) also to the end and have all _ts_meta columns first?

[akuzm]

I think filters on segmentby might be more frequent than ordering, so I put segmentby before the orderby metadata. In general for minmax columns, I think might be good to follow the order specified by the user, especially if we're going to introduce minmax for non-orderby columns. But this is just a vague intuition, haven't really done any research on it.

[jnidzwetzki]

One question regarding the ordering. Rest looks good to me.