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  1. MariaDB Server
  2. MDEV-26721

Histograms are not calculated for geometry columns

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Details

    • Bug
    • Status: Open (View Workflow)
    • Minor
    • Resolution: Unresolved
    • 10.2, 10.3, 10.4, 10.5, 10.6
    • 10.4, 10.5, 10.6
    • GIS, Optimizer
    • None

    Description

      When ANALYZE TABLE .. PERSISTENT is run for geometry columns, the statistics for them is collected and put into mysql.column_stats, but histogram field remains NULL. It is different from, for example, blobs for which statistics aren't collected at all.

      I couldn't find out whether it is intentional. If it is, maybe it's worth mentioning in the KB.

      CREATE OR REPLACE TABLE t (g GEOMETRY);
      INSERT INTO t VALUES (POINT(0,0)),(POINT(1,1)),(POINT(2,2));
       
      SET histogram_type= SINGLE_PREC_HB, histogram_size= 255;
       
      ANALYZE TABLE t PERSISTENT FOR ALL;
       
      SELECT DECODE_HISTOGRAM(hist_type,histogram) FROM mysql.column_stats where table_name = 't';
       
      # Cleanup
      DROP TABLE t;
      

      10.6 27738bd7

      SELECT DECODE_HISTOGRAM(hist_type,histogram) FROM mysql.column_stats where table_name = 't';
      DECODE_HISTOGRAM(hist_type,histogram)
      NULL
      

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            psergei Sergei Petrunia
            elenst Elena Stepanova
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            Dates

              Created:
              Updated:

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