From 4944142ed2ea18c0bdf9be9721c94f74eed1e538 Mon Sep 17 00:00:00 2001
From: Georgy Shelkovy <g.shelkovy@arenadata.io>
Date: Mon, 20 May 2024 12:49:39 +0500
Subject: [PATCH] Revert "rewrite"

This reverts commit 557c13ed380fea930e238084ebf86f9c3fa9444c.
---
 backup/queries_statistics.go | 31 ++++++++-----------------------
 backup/wrappers.go           | 32 ++++++++++----------------------
 2 files changed, 18 insertions(+), 45 deletions(-)

diff --git a/backup/queries_statistics.go b/backup/queries_statistics.go
index 5ebe8c3d2..4f9a4eac7 100644
--- a/backup/queries_statistics.go
+++ b/backup/queries_statistics.go
@@ -11,7 +11,6 @@ import (
 	"github.com/greenplum-db/gp-common-go-libs/dbconn"
 	"github.com/greenplum-db/gp-common-go-libs/gplog"
 	"github.com/greenplum-db/gpbackup/utils"
-	"github.com/jmoiron/sqlx"
 	"github.com/lib/pq"
 )
 
@@ -54,7 +53,7 @@ type AttributeStatistic struct {
 	Values5      pq.StringArray `db:"stavalues5"`
 }
 
-func GetAttributeStatisticsRows(connectionPool *dbconn.DBConn, tables []Table) (*sqlx.Rows, error) {
+func GetAttributeStatistics(connectionPool *dbconn.DBConn, tables []Table) map[uint32][]AttributeStatistic {
 	inheritClause := ""
 	statSlotClause := ""
 	if connectionPool.Version.AtLeast("6") {
@@ -120,20 +119,13 @@ func GetAttributeStatisticsRows(connectionPool *dbconn.DBConn, tables []Table) (
 		inheritClause, statSlotClause, statCollationClause,
 		SchemaFilterClause("n"), utils.SliceToQuotedString(tablenames))
 
-	return connectionPool.Query(query)
-}
-
-func GetAttributeStatistics(connectionPool *dbconn.DBConn, tables []Table) map[uint32][]AttributeStatistic {
-	results, err := GetAttributeStatisticsRows(connectionPool, tables)
+	results := make([]AttributeStatistic, 0)
+	err := connectionPool.Select(&results, query)
 	gplog.FatalOnError(err)
 	stats := make(map[uint32][]AttributeStatistic)
-	for results.Next() {
-		var stat AttributeStatistic
-		err = results.StructScan(&stat)
-		gplog.FatalOnError(err)
+	for _, stat := range results {
 		stats[stat.Oid] = append(stats[stat.Oid], stat)
 	}
-	gplog.FatalOnError(results.Err())
 	return stats
 }
 
@@ -145,7 +137,7 @@ type TupleStatistic struct {
 	RelTuples float64
 }
 
-func GetTupleStatisticsRows(connectionPool *dbconn.DBConn, tables []Table) (*sqlx.Rows, error) {
+func GetTupleStatistics(connectionPool *dbconn.DBConn, tables []Table) map[uint32]TupleStatistic {
 	tablenames := make([]string, 0)
 	for _, table := range tables {
 		tablenames = append(tablenames, table.FQN())
@@ -163,19 +155,12 @@ func GetTupleStatisticsRows(connectionPool *dbconn.DBConn, tables []Table) (*sql
 	ORDER BY n.nspname, c.relname`,
 		SchemaFilterClause("n"), utils.SliceToQuotedString(tablenames))
 
-	return connectionPool.Query(query)
-}
-
-func GetTupleStatistics(connectionPool *dbconn.DBConn, tables []Table) map[uint32]TupleStatistic {
-	results, err := GetTupleStatisticsRows(connectionPool, tables)
+	results := make([]TupleStatistic, 0)
+	err := connectionPool.Select(&results, query)
 	gplog.FatalOnError(err)
 	stats := make(map[uint32]TupleStatistic)
-	for results.Next() {
-		var stat TupleStatistic
-		err = results.StructScan(&stat)
-		gplog.FatalOnError(err)
+	for _, stat := range results {
 		stats[stat.Oid] = stat
 	}
-	gplog.FatalOnError(results.Err())
 	return stats
 }
diff --git a/backup/wrappers.go b/backup/wrappers.go
index a3cead4c5..9cd0376ba 100644
--- a/backup/wrappers.go
+++ b/backup/wrappers.go
@@ -773,30 +773,18 @@ func backupExtendedStatistic(metadataFile *utils.FileWithByteCount) {
 
 func backupTableStatistics(statisticsFile *utils.FileWithByteCount, tables []Table) {
 	backupSessionGUC(statisticsFile)
-	tupleStats, err := GetTupleStatisticsRows(connectionPool, tables)
-	gplog.FatalOnError(err)
-	for tupleStats.Next() {
-		var stat TupleStatistic
-		err = tupleStats.StructScan(&stat)
-		gplog.FatalOnError(err)
-		table := Table{Relation: Relation{Schema: stat.Schema, Name: stat.Table}}
-		tupleQuery := GenerateTupleStatisticsQuery(table, stat)
-		printStatisticsStatementForTable(statisticsFile, globalTOC, table, tupleQuery)
-	}
-	gplog.FatalOnError(tupleStats.Err())
-	attStats, err := GetAttributeStatisticsRows(connectionPool, tables)
-	gplog.FatalOnError(err)
-	for attStats.Next() {
-		var stat AttributeStatistic
-		err = attStats.StructScan(&stat)
-		gplog.FatalOnError(err)
-		table := Table{Relation: Relation{Schema: stat.Schema, Name: stat.Table}}
-		attributeQueries := GenerateAttributeStatisticsQueries(table, stat)
-		for _, attrQuery := range attributeQueries {
-			printStatisticsStatementForTable(statisticsFile, globalTOC, table, attrQuery)
+
+	length := len(tables)
+	slice := 10000
+	for start := 0; start < length; start += slice {
+		end := start + slice
+		if end > length {
+			end = length
 		}
+		attStats := GetAttributeStatistics(connectionPool, tables[start:end])
+		tupleStats := GetTupleStatistics(connectionPool, tables[start:end])
+		PrintStatisticsStatements(statisticsFile, globalTOC, tables[start:end], attStats, tupleStats)
 	}
-	gplog.FatalOnError(attStats.Err())
 }
 
 func backupIncrementalMetadata() {