2026-03-12 20:23:15

2026-03-12 21:23:47 +01:00
parent eab4b36eca
commit 93039b8489
3332 changed files with 699614 additions and 0 deletions
--- a/tpt/tabhisthybrid.sql
+++ b/tpt/tabhisthybrid.sql
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+-- script:  tabhisthybrid.sql
+-- author:  Tanel Poder [tanelpoder.com]
+-- created: Oct 2025 
+-- usage:   @tabhisthybrid [<owner>.]<table_name> <column_name>
+-- example: @tabhisthybrid soe.customers account_mgr_id
+-- 
+-- notes:
+--   I reused the NewDensity logic already written by Mohamed Houri (and Alberto Dell'Era, Jonathan Lewis)
+--   https://www.red-gate.com/simple-talk/databases/oracle-databases/12c-hybrid-histogram/
+--
+--   This script works with HYBRID histograms on NUMBER columns only for now.
+--   I'm hoping to unify this script and my old tabhist.sql to show estimated cardinalities
+--   (for equality filters) for all histogram types and data types someday.
+
+COL phys_bucket            HEAD BUCKET FOR 99999
+COL table_owner            FORMAT A15
+COL table_name             FORMAT A30
+COL column_name            FORMAT A30
+COL data_type              HEAD DATA_TYPE FORMAT A12
+COL histogram_type         HEAD HIST_TYPE FORMAT A12
+COL endpoint_number        FORMAT 9999999999
+COL endpoint_value         HEAD LOOKUP_VALUE FORMAT 9999999999
+COL endpoint_actual_value  FORMAT A40
+COL estimated_rows         FORMAT 9999999999
+COL endpoint_repeat_count  FORMAT 999999
+COL olddensity             FORMAT 0.00000000
+COL newdensity             FORMAT 0.00000000
+
+WITH col AS (
+    SELECT
+        t.owner
+      , t.table_name
+      , t.num_rows
+      , c.column_name
+      , c.data_type
+      , c.histogram
+      , c.sample_size
+      , c.density AS OldDensity
+      , (c.sample_size - c.num_nulls) AS BktCnt
+      , c.num_distinct AS ndv
+      , c.num_buckets
+      , (c.sample_size - c.num_nulls) / c.num_buckets AS pop_bucketSize
+    FROM 
+        dba_tables t
+      , dba_tab_columns c
+    WHERE
+    -- join
+        t.owner       = c.owner
+    AND t.table_name  = c.table_name
+    -- filter
+    AND UPPER(t.table_name)  = UPPER(CASE WHEN INSTR('&1','.')>0 THEN SUBSTR('&1',INSTR('&1','.')+1) ELSE '&1' END)
+    AND UPPER(t.owner)       = UPPER(CASE WHEN INSTR('&1','.')>0 THEN SUBSTR('&1',1,INSTR('&1','.')-1) ELSE USER END)
+    AND UPPER(c.column_name) = UPPER('&2')
+),
+hist AS (
+    SELECT
+        owner
+      , table_name
+      , column_name
+      , endpoint_number
+      , endpoint_repeat_count
+      , endpoint_value
+      , endpoint_actual_value
+    FROM
+        dba_tab_histograms
+    WHERE
+        UPPER(table_name)  = UPPER(CASE WHEN INSTR('&1','.')>0 THEN SUBSTR('&1',INSTR('&1','.')+1) ELSE '&1' END)
+    AND UPPER(owner)       = UPPER(CASE WHEN INSTR('&1','.')>0 THEN SUBSTR('&1',1,INSTR('&1','.')-1) ELSE USER END)
+    AND UPPER(column_name) = UPPER('&2')
+),
+bkt AS (
+    -- newdensity calc for a column (returns 1 row as we are looking into one column of one table)
+    SELECT
+        COUNT(*) PopValCnt
+      , SUM(endpoint_repeat_count) PopBktCnt
+      , ndv
+      , BktCnt
+      , pop_bucketSize
+    FROM
+        col
+      , hist
+    WHERE
+        endpoint_repeat_count > pop_bucketSize
+    GROUP BY
+        ndv
+      , BktCnt
+      , pop_bucketSize
+),
+nd AS (
+    SELECT
+        TRUNC(((BktCnt - PopBktCnt) / BktCnt) / (NDV - PopValCnt), 10) AS NewDensity
+    FROM
+        bkt
+)
+SELECT
+    rownum                             AS phys_bucket
+  , data_type                          AS data_type
+  , histogram                          AS histogram_type
+  , endpoint_value                     AS endpoint_value
+  , CASE
+        -- popular value
+        WHEN
+            histogram = 'HYBRID' AND NVL(endpoint_repeat_count, 0) > 1
+        THEN
+            ROUND(num_rows * (endpoint_repeat_count/sample_size))
+        -- non-popular but is an endpoint
+        WHEN
+            histogram = 'HYBRID' AND NVL(endpoint_repeat_count, 0) = 1
+        THEN
+            ROUND(num_rows * LEAST(newdensity, endpoint_repeat_count / sample_size))
+        -- TODO check if this condition does even exist in the wild
+        WHEN 
+            histogram = 'HYBRID' AND endpoint_number IS NULL
+        THEN
+            -1 
+        ELSE
+            NULL
+    END                                AS card_thisval
+  , TRUNC(c.num_rows * nd.newdensity)  AS card_non_pop
+--  , NVL(endpoint_repeat_count,0)       AS endpoint_repeat_count
+--  , endpoint_number                    AS endpoint_number
+--  , endpoint_actual_value              AS endpoint_actual_value
+--  , olddensity                         AS olddensity
+FROM
+    col  c
+  , hist h
+  , nd -- single row
+WHERE
+    c.owner       = h.owner
+AND c.table_name  = h.table_name
+AND c.column_name = h.column_name
+ORDER BY
+    c.owner, c.table_name, c.column_name, h.endpoint_number
+/