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Commite01d347

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Add missing documentation for argument of amcostestimate()
5262f7a have introduced parallel index scan. In order to estimate thenumber of parallel workers, it adds extra argument to amcostestimate() indexaccess method API function. However, this extra argument was missed in thedocumentation. This commit fixes that.Discussion:https://postgr.es/m/4128fdb4-8b63-2e05-38f6-3125f8c27263%40lab.ntt.co.jpAuthor: Tatsuro Yamada, Alexander KorotkovBackpatch-through: 10
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‎doc/src/sgml/indexam.sgml

Lines changed: 19 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -385,7 +385,8 @@ amcostestimate (PlannerInfo *root,
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Cost *indexStartupCost,
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Cost *indexTotalCost,
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Selectivity *indexSelectivity,
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double *indexCorrelation);
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double *indexCorrelation,
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double *indexPages);
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</programlisting>
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Estimate the costs of an index scan. This function is described fully
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in <xref linkend="index-cost-estimation"/>, below.
@@ -1155,7 +1156,8 @@ amcostestimate (PlannerInfo *root,
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Cost *indexStartupCost,
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Cost *indexTotalCost,
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Selectivity *indexSelectivity,
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double *indexCorrelation);
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double *indexCorrelation,
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double *indexPages);
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</programlisting>
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The first three parameters are inputs:
@@ -1197,7 +1199,7 @@ amcostestimate (PlannerInfo *root,
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</para>
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<para>
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The lastfour parameters are pass-by-reference outputs:
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The lastfive parameters are pass-by-reference outputs:
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<variablelist>
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<varlistentry>
@@ -1236,6 +1238,15 @@ amcostestimate (PlannerInfo *root,
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>*indexPages</parameter></term>
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<listitem>
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<para>
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Set to number of index leaf pages
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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@@ -1283,6 +1294,11 @@ amcostestimate (PlannerInfo *root,
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table.
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</para>
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<para>
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The <parameter>indexPages</parameter> should be set to the number of leaf pages.
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This is used to estimate the number of workers for parallel index scan.
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</para>
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<para>
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When <parameter>loop_count</parameter> is greater than one, the returned numbers
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should be averages expected for any one scan of the index.

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