Avoid unnecessary relation stats query in pg_dump.

The few fields we need can be easily collected in getTables() and
getIndexes() and stored in RelStatsInfo.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reported-by: Andres Freund <andres@anarazel.de>
Co-authored-by: Corey Huinker <corey.huinker@gmail.com>
Co-authored-by: Jeff Davis <pgsql@j-davis.com>
Discussion: https://postgr.es/m/CADkLM=f0a43aTd88xW4xCFayEF25g-7hTrHX_WhV40HyocsUGg@mail.gmail.com

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index afd7928717777d69badf1af8ca437a7d4aef0cc8..a1823914656e2bcbf2d95a6e2b5e3a7e75827b3e 100644 (file)
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -56,6 +56,7 @@
 #include "common/connect.h"
 #include "common/int.h"
 #include "common/relpath.h"
+#include "common/shortest_dec.h"
 #include "compress_io.h"
 #include "dumputils.h"
 #include "fe_utils/option_utils.h"
@@ -524,6 +525,9 @@ main(int argc, char **argv)
    pg_logging_set_level(PG_LOG_WARNING);
    set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pg_dump"));
 
+   /* ensure that locale does not affect floating point interpretation */
+   setlocale(LC_NUMERIC, "C");
+
    /*
     * Initialize what we need for parallel execution, especially for thread
     * support on Windows.
@@ -6814,7 +6818,8 @@ getFuncs(Archive *fout)
  *
  */
 static RelStatsInfo *
-getRelationStatistics(Archive *fout, DumpableObject *rel, char relkind)
+getRelationStatistics(Archive *fout, DumpableObject *rel, int32 relpages,
+                     float reltuples, int32 relallvisible, char relkind)
 {
    if (!fout->dopt->dumpStatistics)
        return NULL;
@@ -6839,6 +6844,9 @@ getRelationStatistics(Archive *fout, DumpableObject *rel, char relkind)
        dobj->components |= DUMP_COMPONENT_STATISTICS;
        dobj->name = pg_strdup(rel->name);
        dobj->namespace = rel->namespace;
+       info->relpages = relpages;
+       info->reltuples = reltuples;
+       info->relallvisible = relallvisible;
        info->relkind = relkind;
        info->postponed_def = false;
 
@@ -6874,6 +6882,8 @@ getTables(Archive *fout, int *numTables)
    int         i_relhasindex;
    int         i_relhasrules;
    int         i_relpages;
+   int         i_reltuples;
+   int         i_relallvisible;
    int         i_toastpages;
    int         i_owning_tab;
    int         i_owning_col;
@@ -6924,7 +6934,7 @@ getTables(Archive *fout, int *numTables)
                         "c.relowner, "
                         "c.relchecks, "
                         "c.relhasindex, c.relhasrules, c.relpages, "
-                        "c.relhastriggers, "
+                        "c.reltuples, c.relallvisible, c.relhastriggers, "
                         "c.relpersistence, "
                         "c.reloftype, "
                         "c.relacl, "
@@ -7088,6 +7098,8 @@ getTables(Archive *fout, int *numTables)
    i_relhasindex = PQfnumber(res, "relhasindex");
    i_relhasrules = PQfnumber(res, "relhasrules");
    i_relpages = PQfnumber(res, "relpages");
+   i_reltuples = PQfnumber(res, "reltuples");
+   i_relallvisible = PQfnumber(res, "relallvisible");
    i_toastpages = PQfnumber(res, "toastpages");
    i_owning_tab = PQfnumber(res, "owning_tab");
    i_owning_col = PQfnumber(res, "owning_col");
@@ -7134,6 +7146,9 @@ getTables(Archive *fout, int *numTables)
 
    for (i = 0; i < ntups; i++)
    {
+       float       reltuples = strtof(PQgetvalue(res, i, i_reltuples), NULL);
+       int32       relallvisible = atoi(PQgetvalue(res, i, i_relallvisible));
+
        tblinfo[i].dobj.objType = DO_TABLE;
        tblinfo[i].dobj.catId.tableoid = atooid(PQgetvalue(res, i, i_reltableoid));
        tblinfo[i].dobj.catId.oid = atooid(PQgetvalue(res, i, i_reloid));
@@ -7233,7 +7248,8 @@ getTables(Archive *fout, int *numTables)
 
        /* Add statistics */
        if (tblinfo[i].interesting)
-           getRelationStatistics(fout, &tblinfo[i].dobj, tblinfo[i].relkind);
+           getRelationStatistics(fout, &tblinfo[i].dobj, tblinfo[i].relpages,
+                                 reltuples, relallvisible, tblinfo[i].relkind);
 
        /*
         * Read-lock target tables to make sure they aren't DROPPED or altered
@@ -7499,6 +7515,9 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
                i_oid,
                i_indrelid,
                i_indexname,
+               i_relpages,
+               i_reltuples,
+               i_relallvisible,
                i_parentidx,
                i_indexdef,
                i_indnkeyatts,
@@ -7552,6 +7571,7 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
    appendPQExpBufferStr(query,
                         "SELECT t.tableoid, t.oid, i.indrelid, "
                         "t.relname AS indexname, "
+                        "t.relpages, t.reltuples, t.relallvisible, "
                         "pg_catalog.pg_get_indexdef(i.indexrelid) AS indexdef, "
                         "i.indkey, i.indisclustered, "
                         "c.contype, c.conname, "
@@ -7659,6 +7679,9 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
    i_oid = PQfnumber(res, "oid");
    i_indrelid = PQfnumber(res, "indrelid");
    i_indexname = PQfnumber(res, "indexname");
+   i_relpages = PQfnumber(res, "relpages");
+   i_reltuples = PQfnumber(res, "reltuples");
+   i_relallvisible = PQfnumber(res, "relallvisible");
    i_parentidx = PQfnumber(res, "parentidx");
    i_indexdef = PQfnumber(res, "indexdef");
    i_indnkeyatts = PQfnumber(res, "indnkeyatts");
@@ -7725,6 +7748,9 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
            char        contype;
            char        indexkind;
            RelStatsInfo *relstats;
+           int32       relpages = atoi(PQgetvalue(res, j, i_relpages));
+           float       reltuples = strtof(PQgetvalue(res, j, i_reltuples), NULL);
+           int32       relallvisible = atoi(PQgetvalue(res, j, i_relallvisible));
 
            indxinfo[j].dobj.objType = DO_INDEX;
            indxinfo[j].dobj.catId.tableoid = atooid(PQgetvalue(res, j, i_tableoid));
@@ -7759,7 +7785,8 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
                indexkind = RELKIND_PARTITIONED_INDEX;
 
            contype = *(PQgetvalue(res, j, i_contype));
-           relstats = getRelationStatistics(fout, &indxinfo[j].dobj, indexkind);
+           relstats = getRelationStatistics(fout, &indxinfo[j].dobj, relpages,
+                                            reltuples, relallvisible, indexkind);
 
            if (contype == 'p' || contype == 'u' || contype == 'x')
            {
@@ -10383,18 +10410,6 @@ dumpComment(Archive *fout, const char *type,
                        catalogId, subid, dumpId, NULL);
 }
 
-/*
- * Tabular description of the parameters to pg_restore_relation_stats()
- * param_name, param_type
- */
-static const char *rel_stats_arginfo[][2] = {
-   {"relation", "regclass"},
-   {"version", "integer"},
-   {"relpages", "integer"},
-   {"reltuples", "real"},
-   {"relallvisible", "integer"},
-};
-
 /*
  * Tabular description of the parameters to pg_restore_attribute_stats()
  * param_name, param_type
@@ -10419,30 +10434,6 @@ static const char *att_stats_arginfo[][2] = {
    {"range_bounds_histogram", "text"},
 };
 
-/*
- * getRelStatsExportQuery --
- *
- * Generate a query that will fetch all relation (e.g. pg_class)
- * stats for a given relation.
- */
-static void
-getRelStatsExportQuery(PQExpBuffer query, Archive *fout,
-                      const char *schemaname, const char *relname)
-{
-   resetPQExpBuffer(query);
-   appendPQExpBufferStr(query,
-                        "SELECT c.oid::regclass AS relation, "
-                        "current_setting('server_version_num') AS version, "
-                        "c.relpages, c.reltuples, c.relallvisible "
-                        "FROM pg_class c "
-                        "JOIN pg_namespace n "
-                        "ON n.oid = c.relnamespace "
-                        "WHERE n.nspname = ");
-   appendStringLiteralAH(query, schemaname, fout);
-   appendPQExpBufferStr(query, " AND c.relname = ");
-   appendStringLiteralAH(query, relname, fout);
-}
-
 /*
  * getAttStatsExportQuery --
  *
@@ -10454,21 +10445,22 @@ getAttStatsExportQuery(PQExpBuffer query, Archive *fout,
                       const char *schemaname, const char *relname)
 {
    resetPQExpBuffer(query);
-   appendPQExpBufferStr(query,
-                        "SELECT c.oid::regclass AS relation, "
-                        "s.attname,"
-                        "s.inherited,"
-                        "current_setting('server_version_num') AS version, "
-                        "s.null_frac,"
-                        "s.avg_width,"
-                        "s.n_distinct,"
-                        "s.most_common_vals,"
-                        "s.most_common_freqs,"
-                        "s.histogram_bounds,"
-                        "s.correlation,"
-                        "s.most_common_elems,"
-                        "s.most_common_elem_freqs,"
-                        "s.elem_count_histogram,");
+   appendPQExpBuffer(query,
+                     "SELECT c.oid::regclass AS relation, "
+                     "s.attname,"
+                     "s.inherited,"
+                     "'%u'::integer AS version, "
+                     "s.null_frac,"
+                     "s.avg_width,"
+                     "s.n_distinct,"
+                     "s.most_common_vals,"
+                     "s.most_common_freqs,"
+                     "s.histogram_bounds,"
+                     "s.correlation,"
+                     "s.most_common_elems,"
+                     "s.most_common_elem_freqs,"
+                     "s.elem_count_histogram,",
+                     fout->remoteVersion);
 
    if (fout->remoteVersion >= 170000)
        appendPQExpBufferStr(query,
@@ -10521,34 +10513,21 @@ appendNamedArgument(PQExpBuffer out, Archive *fout, const char *argname,
  * Append a formatted pg_restore_relation_stats statement.
  */
 static void
-appendRelStatsImport(PQExpBuffer out, Archive *fout, PGresult *res)
+appendRelStatsImport(PQExpBuffer out, Archive *fout, const RelStatsInfo *rsinfo)
 {
-   const char *sep = "";
+   const char *qualname = fmtQualifiedId(rsinfo->dobj.namespace->dobj.name, rsinfo->dobj.name);
+   char        reltuples_str[FLOAT_SHORTEST_DECIMAL_LEN];
 
-   if (PQntuples(res) == 0)
-       return;
+   float_to_shortest_decimal_buf(rsinfo->reltuples, reltuples_str);
 
    appendPQExpBufferStr(out, "SELECT * FROM pg_catalog.pg_restore_relation_stats(\n");
-
-   for (int argno = 0; argno < lengthof(rel_stats_arginfo); argno++)
-   {
-       const char *argname = rel_stats_arginfo[argno][0];
-       const char *argtype = rel_stats_arginfo[argno][1];
-       int         fieldno = PQfnumber(res, argname);
-
-       if (fieldno < 0)
-           pg_fatal("relation stats export query missing field '%s'",
-                    argname);
-
-       if (PQgetisnull(res, 0, fieldno))
-           continue;
-
-       appendPQExpBufferStr(out, sep);
-       appendNamedArgument(out, fout, argname, PQgetvalue(res, 0, fieldno), argtype);
-
-       sep = ",\n";
-   }
-   appendPQExpBufferStr(out, "\n);\n");
+   appendPQExpBuffer(out, "\t'relation', '%s'::regclass,\n", qualname);
+   appendPQExpBuffer(out, "\t'version', '%u'::integer,\n",
+                     fout->remoteVersion);
+   appendPQExpBuffer(out, "\t'relpages', '%d'::integer,\n", rsinfo->relpages);
+   appendPQExpBuffer(out, "\t'reltuples', '%s'::real,\n", reltuples_str);
+   appendPQExpBuffer(out, "\t'relallvisible', '%d'::integer\n);\n",
+                     rsinfo->relallvisible);
 }
 
 /*
@@ -10643,15 +10622,11 @@ dumpRelationStats(Archive *fout, const RelStatsInfo *rsinfo)
    tag = createPQExpBuffer();
    appendPQExpBufferStr(tag, fmtId(dobj->name));
 
-   query = createPQExpBuffer();
    out = createPQExpBuffer();
 
-   getRelStatsExportQuery(query, fout, dobj->namespace->dobj.name,
-                          dobj->name);
-   res = ExecuteSqlQuery(fout, query->data, PGRES_TUPLES_OK);
-   appendRelStatsImport(out, fout, res);
-   PQclear(res);
+   appendRelStatsImport(out, fout, rsinfo);
 
+   query = createPQExpBuffer();
    getAttStatsExportQuery(query, fout, dobj->namespace->dobj.name,
                           dobj->name);
    res = ExecuteSqlQuery(fout, query->data, PGRES_TUPLES_OK);

diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index f08f5905aa3759d2743a8c398e1032af003692fa..9d6a4857c4bf7d2da87c1d16fb3c414a5277d182 100644 (file)
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -328,7 +328,7 @@ typedef struct _tableInfo
    Oid         owning_tab;     /* OID of table owning sequence */
    int         owning_col;     /* attr # of column owning sequence */
    bool        is_identity_sequence;
-   int         relpages;       /* table's size in pages (from pg_class) */
+   int32       relpages;       /* table's size in pages (from pg_class) */
    int         toastpages;     /* toast table's size in pages, if any */
 
    bool        interesting;    /* true if need to collect more data */
@@ -438,6 +438,9 @@ typedef struct _indexAttachInfo
 typedef struct _relStatsInfo
 {
    DumpableObject dobj;
+   int32       relpages;
+   float       reltuples;
+   int32       relallvisible;
    char        relkind;        /* 'r', 'm', 'i', etc */
    bool        postponed_def;  /* stats must be postponed into post-data */
 } RelStatsInfo;