[5587] PostgreSQL support for shared lease stats implementation

src/share/database/scripts/pgsql/dhcpdb_create.pgsql
    Adds lease<4/6>_stat tables and triggers
src/share/database/scripts/pgsql/dhcpdb_drop.pgsql
    Added drops for lease<4/6>_stat tables and triggers

src/share/database/scripts/pgsql/upgrade_3.3_to_4.0.sh.in
    Adds lease<4/6>_stat tables and triggers
    Populates stat tables from existing lease table content
src/bin/admin/tests/mysql_tests.sh.in
    mysql_lease6_stat_per_type() - fixed typo in test

src/bin/admin/tests/pgsql_tests.sh.in
    run_statement() - new convenience fucntion for
    running statement with option expected outcome

    pgsql_upgrade_schema_to_version() - new function
    which converts the existing schema to a target version

    pgsql_lease4_stat_test() - tests v4 stat table and
    triggers in an new database

    pgsql_lease6_stat_test() - tests v6 stat table and
    triggers in an new database.

    pgsql_lease6_stat_per_type() - helper function which
    tests v6 stat table and triggers using a given address
    and lease type

    pgsql_lease_stat_upgrade_test() - tests data migration,
    stat table and trigger operations on an upgraded database

src/lib/dhcpsrv/pgsql_lease_mgr.*
    Added new SQL statements for lease stats queries

    PgSqlLeaseStatsQuery
        Constructors - added variants to support where clause params
        start() - modified to support query variants based
        on where clause params

    PgSqlLeaseMgr
        Added start variants:
        - startSubnetLeaseStatsQuery4(const SubnetID& subnet_id)
        - startSubnetRangeLeaseStatsQuery4(const SubnetID& first_subnet_id,
                                         const SubnetID& last_subnet_id)

src/lib/dhcpsrv/tests/pgsql_lease_mgr_unittest.cc
    New unit tests:
    - TEST_F(PgSqlLeaseMgrTest, leaseStatsQuery4)
    - TEST_F(PgSqlLeaseMgrTest, leaseStatsQuery6)

src/bin/admin/tests/mysql_tests.sh.in

@@ -664,7 +664,7 @@ mysql_lease6_stat_per_type() {
     run_statement "#6" "$qry" 1
 
     # delete the lease
-    qry="delete from lease6 where address = 111;"
+    qry="delete from lease6 where address = $addr;"
     run_statement "#7" "$qry"
 
     # leases count for declined state should be 0

src/bin/admin/tests/pgsql_tests.sh.in

@@ -1,6 +1,6 @@
 #!/bin/sh
 
-# Copyright (C) 2015-2017 Internet Systems Consortium, Inc. ("ISC")
+# Copyright (C) 2015-2018 Internet Systems Consortium, Inc. ("ISC")
 #
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -23,6 +23,37 @@ db_host="localhost"
 # Set location of the kea-admin.
 keaadmin=@abs_top_builddir@/src/bin/admin/kea-admin
 
+# Convenience function for running an SQL statement
+# param hdr - text message to prepend to any error
+# param qry - SQL statement to run
+# param exp_valu - optional expected value.  This can be used IF the SQL statement
+# generates a single value, such as a SELECT which returns one column for one row.
+# Examples:
+#
+#   qry="insert into lease6 (address, lease_type, subnet_id, state) values ($addr,$ltype,1,0);"
+#   run_statement "#2" "$qry"
+#
+#   qry="select leases from lease6_stat where subnet_id = 1 and lease_type = $ltype and state = 0";
+#   run_statement "#3" "$qry" 1
+run_statement() {
+    hdr="$1";shift;
+    qry="$1";shift;
+    exp_value="$1";
+
+    # Execute the statment
+    value=`pgsql_execute "${qry}"`
+    ERRCODE=$?
+
+    # Execution should succeed
+    assert_eq 0 $ERRCODE "$hdr: SQL=[$qry] failed: (expected status code %d, returned %d)"
+
+    # If there's an expected value, test it
+    if [ "x$exp_value" != "x" ]
+    then
+        assert_str_eq "$exp_value" "$value" "$hdr: SQL=[$qry] wrong: (expected value %s, returned %s)"
+    fi
+}
+
 # Wipe all tables from the DB:
 pgsql_wipe() {
     printf "Wiping whole database %s\n" $db_name
@@ -437,8 +468,319 @@ sed 's/<timestamp3>/$local_timestamp3/g' "
     test_finish 0
 }
 
+# Upgrades an existing schema to a target newer version
+# param target_version - desired schema version as "major.minor"
+pgsql_upgrade_schema_to_version() {
+    target_version=$1
+
+    # Check if the scripts directory exists at all.
+    if [ ! -d ${db_scripts_dir}/pgsql ]; then
+        log_error "Invalid scripts directory: ${db_scripts_dir}/pgsql"
+        exit 1
+    fi
+
+    # Check if there are any files in it
+    num_files=$(find ${db_scripts_dir}/pgsql/upgrade*.sh -type f | wc -l)
+    if [ $num_files -eq 0 ]; then
+        log_error "No scripts in ${db_scripts_dir}/pgsql?"
+        exit 1
+    fi
+
+    # Postgres psql does not accept pw on command line, but can do it
+    # thru an env
+    export PGPASSWORD=$db_password
+
+    for script in ${db_scripts_dir}/pgsql/upgrade*.sh
+    do
+        if [ $version = "$target_version" ]
+        then
+            break;
+        fi
+
+        echo "Processing $script file..."
+        sh ${script} -U ${db_user} -h ${db_host} -d ${db_name}
+
+        version=`pgsql_version`
+    done
+
+    echo "Schema upgraded to $version"
+}
+
+# Verifies lease4_stat trigger operations on
+# an new, empty database.  It inserts, updates, and
+# deletes various leases, checking lease4_stat
+# values along the way.
+pgsql_lease4_stat_test() {
+    test_start "pgsql.lease4_stat_test"
+
+    # Let's wipe the whole database
+    pgsql_wipe
+
+    # Ok, now let's initialize the database
+    ${keaadmin} lease-init pgsql -u $db_user -p $db_password -n $db_name -d $db_scripts_dir
+    ERRCODE=$?
+    assert_eq 0 $ERRCODE "kea-admin lease-init pgsql returned non-zero status code %d, expected %d"
+
+    # Verify lease4 stat table is present
+    qry="select count(subnet_id) from lease4_stat"
+    run_statement "#1" "$qry" 0
+
+    # Insert lease4
+    qry="insert into lease4 (address, subnet_id, state) values (111,1,0)"
+    run_statement "#2" "$qry"
+
+    # Assigned state count should be 1
+    qry="select leases from lease4_stat where subnet_id = 1 and state = 0"
+    run_statement "#3" "$qry" 1
+
+    # Set lease state to declined
+    qry="update lease4 set state = 1 where address = 111"
+    run_statement "#4" "$qry"
+
+    # Leases state count for assigned should be 0
+    qry="select leases from lease4_stat where subnet_id = 1 and state = 0"
+    run_statement "#5" "$qry" 0
+
+    # Leases state count for declined should be 1
+    qry="select leases from lease4_stat where subnet_id = 1 and state = 1"
+    run_statement "#6" "$qry" 1
+
+    # Delete the lease
+    qry="delete from lease4 where address = 111"
+    run_statement "#7" "$qry"
+
+    # Leases state count for declined should be 0
+    qry="select leases from lease4_stat where subnet_id = 1 and state = 1"
+    run_statement "#8" "$qry" 0
+
+    # Let's wipe the whole database
+    pgsql_wipe
+
+    test_finish 0
+}
+
+# Verifies that lease6_stat triggers operate correctly
+# for using a given address and lease_type.  It will
+# insert a lease, update it, and delete checking the
+# lease stat counts along the way.  It assumes the
+# database has been created but is empty.
+# param addr - address to use to add to subnet 1
+# param ltype - type of lease to create
+pgsql_lease6_stat_per_type() {
+    addr=$1;shift;
+    ltype=$1;
+
+    # insert a lease6 for addr and ltype, state assigned
+    qry="insert into lease6 (address, lease_type, subnet_id, state) values ('$addr',$ltype,1,0);"
+    run_statement "#2" "$qry"
+
+    # assigned stat should be 1
+    qry="select leases from lease6_stat where subnet_id = 1 and lease_type = $ltype and state = 0";
+    run_statement "#3" "$qry" 1
+
+    # update the lease, changing state to declined
+    qry="update lease6 set state = 1 where address = '$addr'"
+    run_statement "#4" "$qry"
+
+    # leases stat for assigned state should be 0
+    qry="select leases from lease6_stat where subnet_id = 1 and lease_type = $ltype and  state = 0";
+    run_statement "#5" "$qry" 0
+
+    # leases count for declined state should be 1
+    qry="select leases from lease6_stat where subnet_id = 1 and lease_type = $ltype and  state = 1";
+    run_statement "#6" "$qry" 1
+
+    # delete the lease
+    qry="delete from lease6 where address = '$addr';"
+    run_statement "#7" "$qry"
+
+    # leases count for declined state should be 0
+    qry="select leases from lease6_stat where subnet_id = 1 and lease_type = $ltype and  state = 0";
+    run_statement "#6" "$qry" 0
+}
+
+# Verifies that lease6_stat triggers operation correctly
+# for both NA and PD lease types, pgsql_lease6_stat_per_type()
+pgsql_lease6_stat_test() {
+
+    test_start "pgsql.lease6_stat_test"
+
+    # Let's wipe the whole database
+    pgsql_wipe
+
+    # Ok, now let's initialize the database
+    ${keaadmin} lease-init pgsql -u $db_user -p $db_password -n $db_name -d $db_scripts_dir
+    ERRCODE=$?
+
+    assert_eq 0 $ERRCODE "kea-admin lease-init pgsql returned non-zero status code %d, expected %d"
+
+    # verify lease6 stat table is present
+    qry="select count(subnet_id) from lease6_stat"
+    run_statement "#1" "$qry"
+
+    # Test for address 111, NA lease type
+    pgsql_lease6_stat_per_type "111" "0"
+
+    # Test for address 222, PD lease type
+    pgsql_lease6_stat_per_type "222" "1"
+
+    # Let's wipe the whole database
+    pgsql_wipe
+
+    test_finish 0
+}
+
+# Verifies that you can upgrade from earlier version and
+# lease<4/6>_stat tables will be populated based on existing
+# leases and that the stat triggers work properly.
+pgsql_lease_stat_upgrade_test() {
+    test_start "pgsql.lease_stat_upgrade_test"
+
+    # Let's wipe the whole database
+    pgsql_wipe
+
+    # We need to create an older database with lease data so we can
+    # verify the upgrade mechanisms which prepopulate the lease stat
+    # tables.
+    #
+    # Initialize database to scheme 1.0.
+    pgsql_execute_script @abs_top_srcdir@/src/bin/admin/tests/dhcpdb_create_1.0.pgsql
+    assert_eq 0 $? "cannot initialize 1.0 database, expected exit code: %d, actual: %d"
+
+    # Now upgrade to schema 2.0, this has lease_state in it
+    pgsql_upgrade_schema_to_version 2.0
+
+    # Now we need insert some leases to "migrate" for both v4 and v6
+    qry=\
+"insert into lease4 (address, subnet_id, state) values (111,10,0);\
+ insert into lease4 (address, subnet_id, state) values (222,10,0);\
+ insert into lease4 (address, subnet_id, state) values (333,10,1);\
+ insert into lease4 (address, subnet_id, state) values (444,10,2);\
+ insert into lease4 (address, subnet_id, state) values (555,77,0);"
+    run_statement "insert v4 leases" "$qry"
+
+    qry=\
+"insert into lease6 (address, lease_type, subnet_id, state) values (111,0,40,0);\
+ insert into lease6 (address, lease_type, subnet_id, state) values (222,0,40,1);\
+ insert into lease6 (address, lease_type, subnet_id, state) values (333,1,40,0);\
+ insert into lease6 (address, lease_type, subnet_id, state) values (444,1,50,0);\
+ insert into lease6 (address, lease_type, subnet_id, state) values (555,1,50,0);\
+ insert into lease6 (address, lease_type, subnet_id, state) values (666,1,40,2);"
+    run_statement "insert v6 leases" "$qry"
+
+    # Ok, we have a 4.0 database with leases. Let's upgrade it to 6.0
+    ${keaadmin} lease-upgrade pgsql -u $db_user -p $db_password -n $db_name -d $db_scripts_dir
+    ERRCODE=$?
+
+    #
+    # First we'll verify lease4_stats are correct after migration.
+    #
+
+    # Assigned leases for subnet 10 should be 2
+    qry="select leases from lease4_stat where subnet_id = 10 and state = 0"
+    run_statement "#4.1" "$qry" 2
+
+    # Assigned leases for subnet 77 should be 1
+    qry="select leases from lease4_stat where subnet_id = 77 and state = 0"
+    run_statement "#4.2" "$qry" 1
+
+    # Should be no records for EXPIRED
+    qry="select count(subnet_id) from lease4_stat where state = 2"
+    run_statement "#4.3" "$qry" 0
+
+    #
+    # Now we'll verify v4 trigger operation for insert,update, and delete
+    #
+
+    # Insert a new lease subnet 77
+    qry="insert into lease4 (address, subnet_id, state) values (777,77,0);"
+    run_statement "#4.4" "$qry"
+
+    # Assigned count for subnet 77 should be 2
+    qry="select leases from lease4_stat where subnet_id = 77 and state = 0"
+    run_statement "#4.5" "$qry" 2
+
+    # Update the state of the new lease to declined
+    qry="update lease4 set state = 1 where address = 777;"
+    run_statement "#4.6" "$qry"
+
+    # Assigned count for subnet 77 should be 1 again
+    qry="select leases from lease4_stat where subnet_id = 77 and state = 0"
+    run_statement "#4.7" "$qry" 1
+
+    # Declined count for subnet 77 should be 1
+    qry="select leases from lease4_stat where subnet_id = 77 and state = 1"
+    run_statement "#4.8" "$qry" 1
+
+    # Delete the lease.
+    qry="delete from lease4 where address = 777;"
+    run_statement "#4.9" "$qry"
+
+    # Declined count for subnet 77 should be 0
+    qry="select leases from lease4_stat where subnet_id = 77 and state = 1"
+    run_statement "#4.10" "$qry" 0
+
+    #
+    # Next we'll verify lease6_stats are correct after migration.
+    #
+
+    # Assigned leases for subnet 40 should be 1
+    qry="select leases from lease6_stat where subnet_id = 40 and lease_type = 0 and state = 0"
+    run_statement "#6.1" "$qry" 1
+
+    # Assigned (PD) leases for subnet 40 should be 1
+    qry="select leases from lease6_stat where subnet_id = 40 and lease_type = 1 and state = 0"
+    run_statement "#6.2" "$qry" 1
+
+    # Declined leases for subnet 40 should be 1
+    qry="select leases from lease6_stat where subnet_id = 40 and lease_type = 0 and state = 1"
+    run_statement "#6.3" "$qry" 1
+
+    # Assigned (PD) leases for subnet 50 should be 2
+    qry="select leases from lease6_stat where subnet_id = 50 and lease_type = 1 and state = 0"
+    run_statement "#6.4" "$qry" 2
+
+    # Should be no records for EXPIRED
+    qry="select count(subnet_id) from lease4_stat where state = 2"
+    run_statement "#6.5" "$qry" 0
+
+    #
+    # Finally we'll verify v6 trigger operation for insert,update, and delete
+    #
+
+    # Insert a new lease subnet 50
+    qry="insert into lease6 (address, subnet_id, lease_type, state) values ('777',50,1,0)"
+    run_statement "#6.5" "$qry"
+
+    # Assigned count for subnet 50 should be 3
+    qry="select leases from lease6_stat where subnet_id = 50 and lease_type = 1 and state = 0"
+    run_statement "#6.6" "$qry" 3
+
+    # Update the state of the new lease to expired
+    qry="update lease6 set state = 2 where address = '777';"
+    run_statement "#6.7" "$qry"
+
+    # Assigned count for subnet 50 should be 2 again
+    qry="select leases from lease6_stat where subnet_id = 50 and lease_type = 1 and state = 0"
+    run_statement "#6.8" "$qry" 2
+
+    # Delete another PD lease.
+    qry="delete from lease6 where address = '555'"
+    run_statement "#6.9" "$qry"
+
+    # Assigned leases for subnet 50 should be 1
+    qry="select leases from lease6_stat where subnet_id = 50 and lease_type = 1 and state = 0"
+    run_statement "#6.10" "$qry" 1
+
+    # Let's wipe the whole database
+    pgsql_wipe
+}
+
 pgsql_lease_init_test
 pgsql_lease_version_test
 pgsql_upgrade_test
 pgsql_lease4_dump_test
 pgsql_lease6_dump_test
+pgsql_lease4_stat_test
+pgsql_lease6_stat_test
+pgsql_lease_stat_upgrade_test

src/lib/dhcpsrv/pgsql_lease_mgr.cc

@@ -251,20 +251,49 @@ PgSqlTaggedStatement tagged_statements[] = {
         "hwaddr = $13, hwtype = $14, hwaddr_source = $15, "
         "state = $16 "
       "WHERE address = $17"},
-
+    // ALL_LEASE4_STATS
-    // RECOUNT_LEASE4_STATS,
     { 0, { OID_NONE },
-      "recount_lease4_stats",
+      "all_lease4_stats",
-      "SELECT subnet_id, state, count(state) as state_count "
+      "SELECT subnet_id, state, leases as state_count"
-      "FROM lease4 GROUP BY subnet_id, state ORDER BY subnet_id"},
+      "  FROM lease4_stat ORDER BY subnet_id, state"},
 
-    // RECOUNT_LEASE6_STATS,
+    // SUBNET_LEASE4_STATS
+    { 1, { OID_INT8 },
+      "subnet_lease4_stats",
+      "SELECT subnet_id, state, leases as state_count"
+      "  FROM lease4_stat "
+      "  WHERE subnet_id = $1 "
+      "  ORDER BY state"},
+
+    // SUBNET_RANGE_LEASE4_STATS
+    { 2, { OID_INT8, OID_INT8 },
+      "subnet_range_lease4_stats",
+      "SELECT subnet_id, state, leases as state_count"
+      "  FROM lease4_stat "
+      "  WHERE subnet_id >= $1 and subnet_id <= $2 "
+      "  ORDER BY subnet_id, state"},
+
+    // ALL_LEASE6_STATS,
     { 0, { OID_NONE },
-      "recount_lease6_stats",
+     "all_lease6_stats",
-      "SELECT subnet_id, lease_type, state, count(state) as state_count "
+     "SELECT subnet_id, lease_type, state, leases as state_count"
-      "FROM lease6 GROUP BY subnet_id, lease_type, state "
+     "  FROM lease6_stat ORDER BY subnet_id, lease_type, state" },
-      "ORDER BY subnet_id"},
 
+    // SUBNET_LEASE6_STATS
+    { 1, { OID_INT8 },
+      "subnet_lease6_stats",
+      "SELECT subnet_id, lease_type, state, leases as state_count"
+      "  FROM lease6_stat "
+      "  WHERE subnet_id = $1 "
+      "  ORDER BY lease_type, state" },
+
+    // SUBNET_RANGE_LEASE6_STATS
+    { 2, { OID_INT8, OID_INT8 },
+      "subnet_range_lease6_stats",
+      "SELECT subnet_id, lease_type, state, leases as state_count"
+      "  FROM lease6_stat "
+      "  WHERE subnet_id >= $1 and subnet_id <= $2 "
+      "  ORDER BY subnet_id, lease_type, state" },
     // End of list sentinel
     { 0,  { 0 }, NULL, NULL}
 };
@@ -814,7 +843,9 @@ private:
 ///
 class PgSqlLeaseStatsQuery : public LeaseStatsQuery {
 public:
-    /// @brief Constructor
+    /// @brief Constructor to query for all subnets' stats
+    ///
+    ///  The query created will return statistics for all subnets
     ///
     /// @param conn A open connection to the database housing the lease data
     /// @param statement The lease data SQL prepared statement to execute
@@ -826,18 +857,75 @@ public:
          fetch_type_(fetch_type) {
     }
 
+    /// @brief Constructor to query for a single subnet's stats
+    ///
+    /// The query created will return statistics for a single subnet
+    ///
+    /// @param conn A open connection to the database housing the lease data
+    /// @param statement The lease data SQL prepared statement to execute
+    /// @param fetch_type Indicates if query supplies lease type
+    /// @param subnet_id id of the subnet for which stats are desired
+    PgSqlLeaseStatsQuery(PgSqlConnection& conn, PgSqlTaggedStatement& statement,
+                         const bool fetch_type, const SubnetID& subnet_id)
+        : LeaseStatsQuery(subnet_id), conn_(conn), statement_(statement), result_set_(),
+          next_row_(0), fetch_type_(fetch_type) {
+    }
+
+    /// @brief Constructor to query for the stats for a range of subnets
+    ///
+    /// The query created will return statistics for the inclusive range of
+    /// subnets described by first and last sunbet IDs.
+    ///
+    /// @param conn A open connection to the database housing the lease data
+    /// @param statement The lease data SQL prepared statement to execute
+    /// @param fetch_type Indicates if query supplies lease type
+    /// @param first_subnet_id first subnet in the range of subnets
+    /// @param last_subnet_id last subnet in the range of subnets
+    PgSqlLeaseStatsQuery(PgSqlConnection& conn, PgSqlTaggedStatement& statement,
+                         const bool fetch_type, const SubnetID& first_subnet_id,
+                         const SubnetID& last_subnet_id)
+        : LeaseStatsQuery(first_subnet_id, last_subnet_id), conn_(conn), statement_(statement),
+          result_set_(), next_row_(0), fetch_type_(fetch_type) {
+    }
+
     /// @brief Destructor
     virtual ~PgSqlLeaseStatsQuery() {};
 
     /// @brief Creates the lease statistical data result set
     ///
     /// The result set is populated by executing a  prepared SQL query
-    /// against the database which sums the leases per lease state per
+    /// against the database fetches the lease count per lease state per
-    /// subnet id.
+    /// (per least type - v6 only) per subnet id.
+    ///
+    /// Depending upon the selection mode, the query will have either no
+    /// parameters (for all subnets), a subnet id for a single subnet, or
+    /// a first and last subnet id for a subnet range.
     void start() {
-        // The query has no parameters, so we only need it's name.
+
-        result_set_.reset(new PgSqlResult(PQexecPrepared(conn_, statement_.name,
+        if (getSelectMode() == ALL_SUBNETS) {
-                                          0, NULL, NULL, NULL, 0)));
+            // Run the query with no where clause parameters.
+            result_set_.reset(new PgSqlResult(PQexecPrepared(conn_, statement_.name,
+                                                             0, 0, 0, 0, 0)));
+        } else {
+            // Set up the WHERE clause values
+            PsqlBindArray parms;
+
+            // Add first_subnet_id used by both single and range.
+            std::string subnet_id_str = boost::lexical_cast<std::string>(getFirstSubnetID());
+            parms.add(subnet_id_str);
+
+            // Add last_subnet_id for range.
+            if (getSelectMode() == SUBNET_RANGE) {
+                // Add last_subnet_id used by range.
+                string subnet_id_str = boost::lexical_cast<std::string>(getLastSubnetID());
+                parms.add(subnet_id_str);
+            }
+
+            // Run the query with where clause parameters.
+            result_set_.reset(new PgSqlResult(PQexecPrepared(conn_, statement_.name,
+                                              parms.size(), &parms.values_[0],
+                                              &parms.lengths_[0], &parms.formats_[0], 0)));
+        }
 
         conn_.checkStatementError(*result_set_, statement_);
     }
@@ -1511,9 +1599,26 @@ PgSqlLeaseMgr::deleteExpiredReclaimedLeasesCommon(const uint32_t secs,
 LeaseStatsQueryPtr
 PgSqlLeaseMgr::startLeaseStatsQuery4() {
     LeaseStatsQueryPtr query(
-        new PgSqlLeaseStatsQuery(conn_,
+        new PgSqlLeaseStatsQuery(conn_, tagged_statements[ALL_LEASE4_STATS], false));
-                                 tagged_statements[RECOUNT_LEASE4_STATS],
+    query->start();
-                                 false));
+    return(query);
+}
+
+LeaseStatsQueryPtr
+PgSqlLeaseMgr::startSubnetLeaseStatsQuery4(const SubnetID& subnet_id) {
+    LeaseStatsQueryPtr query(
+        new PgSqlLeaseStatsQuery(conn_, tagged_statements[SUBNET_LEASE4_STATS],
+                                 false, subnet_id));
+    query->start();
+    return(query);
+}
+
+LeaseStatsQueryPtr
+PgSqlLeaseMgr::startSubnetRangeLeaseStatsQuery4(const SubnetID& first_subnet_id,
+                                                   const SubnetID& last_subnet_id) {
+    LeaseStatsQueryPtr query(
+        new PgSqlLeaseStatsQuery(conn_, tagged_statements[SUBNET_RANGE_LEASE4_STATS],
+                                 false, first_subnet_id, last_subnet_id));
     query->start();
     return(query);
 }
@@ -1521,9 +1626,26 @@ PgSqlLeaseMgr::startLeaseStatsQuery4() {
 LeaseStatsQueryPtr
 PgSqlLeaseMgr::startLeaseStatsQuery6() {
     LeaseStatsQueryPtr query(
-        new PgSqlLeaseStatsQuery(conn_,
+        new PgSqlLeaseStatsQuery(conn_, tagged_statements[ALL_LEASE6_STATS], true));
-                                 tagged_statements[RECOUNT_LEASE6_STATS],
+    query->start();
-                                 true));
+    return(query);
+}
+
+LeaseStatsQueryPtr
+PgSqlLeaseMgr::startSubnetLeaseStatsQuery6(const SubnetID& subnet_id) {
+    LeaseStatsQueryPtr query(
+        new PgSqlLeaseStatsQuery(conn_, tagged_statements[SUBNET_LEASE6_STATS],
+                                 true, subnet_id));
+    query->start();
+    return(query);
+}
+
+LeaseStatsQueryPtr
+PgSqlLeaseMgr::startSubnetRangeLeaseStatsQuery6(const SubnetID& first_subnet_id,
+                                                const SubnetID& last_subnet_id) {
+    LeaseStatsQueryPtr query(
+        new PgSqlLeaseStatsQuery(conn_, tagged_statements[SUBNET_RANGE_LEASE6_STATS],
+                                 true, first_subnet_id, last_subnet_id));
     query->start();
     return(query);
 }

src/lib/dhcpsrv/pgsql_lease_mgr.h

@@ -338,22 +338,65 @@ public:
     ///
     /// It creates an instance of a PgSqlLeaseStatsQuery4 and then
     /// invokes its start method, which fetches its statistical data
-    /// result set by executing the RECOUNT_LEASE_STATS4 query.
+    /// result set by executing the ALL_LEASE_STATS4 query.
     /// The query object is then returned.
     ///
     /// @return The populated query as a pointer to an LeaseStatsQuery
     virtual LeaseStatsQueryPtr startLeaseStatsQuery4();
 
+    /// @brief Creates and runs the IPv4 lease stats query for a single subnet
+    ///
+    /// It creates an instance of a PgSqlLeaseStatsQuery4 for a single subnet
+    /// query and then invokes its start method in which the query constructs its
+    /// statistical data result set.  The query object is then returned.
+    ///
+    /// @param subnet_id id of the subnet for which stats are desired
+    /// @return A populated LeaseStatsQuery
+    virtual LeaseStatsQueryPtr startSubnetLeaseStatsQuery4(const SubnetID& subnet_id);
+
+
+    /// @brief Creates and runs the IPv4 lease stats query for a single subnet
+    ///
+    /// It creates an instance of a PgSqlLeaseStatsQuery4 for a subnet range
+    /// query and then invokes its start method in which the query constructs its
+    /// statistical data result set.  The query object is then returned.
+    ///
+    /// @param first_subnet_id first subnet in the range of subnets
+    /// @param last_subnet_id last subnet in the range of subnets
+    /// @return A populated LeaseStatsQuery
+    virtual LeaseStatsQueryPtr startSubnetRangeLeaseStatsQuery4(const SubnetID& first_subnet_id,
+                                                                const SubnetID& last_subnet_id);
     /// @brief Creates and runs the IPv6 lease stats query
     ///
     /// It creates an instance of a PgSqlLeaseStatsQuery and then
     /// invokes its start method, which fetches its statistical data
-    /// result set by executing the RECOUNT_LEASE_STATS6 query.
+    /// result set by executing the ALL_LEASE_STATS6 query.
     /// The query object is then returned.
     ///
     /// @return The populated query as a pointer to an LeaseStatsQuery
     virtual LeaseStatsQueryPtr startLeaseStatsQuery6();
 
+    /// @brief Creates and runs the IPv6 lease stats query for a single subnet
+    ///
+    /// It creates an instance of a PgSqlLeaseStatsQuery6 for a single subnet
+    /// query and then invokes its start method in which the query constructs its
+    /// statistical data result set.  The query object is then returned.
+    ///
+    /// @param subnet_id id of the subnet for which stats are desired
+    /// @return A populated LeaseStatsQuery
+    virtual LeaseStatsQueryPtr startSubnetLeaseStatsQuery6(const SubnetID& subnet_id);
+
+    /// @brief Creates and runs the IPv6 lease stats query for a single subnet
+    ///
+    /// It creates an instance of a PgSqlLeaseStatsQuery6 for a subnet range
+    /// query and then invokes its start method in which the query constructs its
+    /// statistical data result set.  The query object is then returned.
+    ///
+    /// @param first_subnet_id first subnet in the range of subnets
+    /// @param last_subnet_id last subnet in the range of subnets
+    /// @return A populated LeaseStatsQuery
+    virtual LeaseStatsQueryPtr startSubnetRangeLeaseStatsQuery6(const SubnetID& first_subnet_id,
+                                                                const SubnetID& last_subnet_id);
     /// @brief Removes specified IPv4 leases.
     ///
     /// This rather dangerous method is able to remove all leases from specified
@@ -448,8 +491,12 @@ public:
         INSERT_LEASE6,              // Add entry to lease6 table
         UPDATE_LEASE4,              // Update a Lease4 entry
         UPDATE_LEASE6,              // Update a Lease6 entry
-        RECOUNT_LEASE4_STATS,       // Fetch IPv4 lease statistical data
+        ALL_LEASE4_STATS,           // Fetches IPv4 lease statistics
-        RECOUNT_LEASE6_STATS,       // Fetch IPv4 lease statistical data
+        SUBNET_LEASE4_STATS,        // Fetched IPv4 lease stats for a single subnet.
+        SUBNET_RANGE_LEASE4_STATS,  // Fetched IPv4 lease stats for a subnet range.
+        ALL_LEASE6_STATS,           // Fetches IPv6 lease statistics
+        SUBNET_LEASE6_STATS,        // Fetched IPv6 lease stats for a single subnet.
+        SUBNET_RANGE_LEASE6_STATS,  // Fetched IPv6 lease stats for a subnet range.
         NUM_STATEMENTS              // Number of statements
     };
 

src/lib/dhcpsrv/tests/pgsql_lease_mgr_unittest.cc

@@ -530,4 +530,14 @@ TEST_F(PgSqlLeaseMgrTest, DISABLED_wipeLeases6) {
     testWipeLeases6();
 }
 
+// Tests v4 lease stats query variants.
+TEST_F(PgSqlLeaseMgrTest, leaseStatsQuery4) {
+    testLeaseStatsQuery4();
+}
+
+// Tests v6 lease stats query variants.
+TEST_F(PgSqlLeaseMgrTest, leaseStatsQuery6) {
+    testLeaseStatsQuery6();
+}
+
 }  // namespace

src/share/database/scripts/pgsql/dhcpdb_create.pgsql

@@ -570,6 +570,184 @@ CREATE INDEX lease6_by_subnet_id_lease_type ON lease6 (subnet_id, lease_type);
 DROP INDEX lease6_by_iaid_subnet_id_duid;
 CREATE INDEX lease6_by_duid_iaid_subnet_id ON lease6 (duid, iaid, subnet_id);
 
+-- Create v4 lease statistics table
+CREATE TABLE lease4_stat (
+    subnet_id BIGINT NOT NULL,
+    state INT8 NOT NULL,
+    leases BIGINT,
+    PRIMARY KEY (subnet_id, state)
+);
+
+--
+-- Create v4 insert trigger procedure
+CREATE FUNCTION proc_stat_lease4_insert () RETURNS trigger AS $stat_lease4_insert$
+BEGIN
+    IF NEW.state < 2 THEN
+        UPDATE lease4_stat
+            SET leases = leases + 1
+            WHERE subnet_id = NEW.subnet_id AND state = NEW.state;
+
+        IF NOT FOUND THEN
+            INSERT INTO lease4_stat VALUES (new.subnet_id, new.state, 1);
+        END IF;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+$stat_lease4_insert$ LANGUAGE plpgsql;
+
+-- Create v4 insert trigger procedure
+CREATE TRIGGER stat_lease4_insert
+AFTER INSERT ON lease4
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease4_insert();
+
+--
+-- Create v4 update trigger procedure
+CREATE FUNCTION proc_stat_lease4_update () RETURNS trigger AS $stat_lease4_update$
+BEGIN
+    IF OLD.state != NEW.state THEN
+        IF OLD.state < 2 THEN
+            -- Decrement the old state count if record exists
+            UPDATE lease4_stat SET leases = leases - 1
+            WHERE subnet_id = OLD.subnet_id AND state = OLD.state;
+        END IF;
+
+        IF NEW.state < 2 THEN
+            -- Increment the new state count if record exists
+            UPDATE lease4_stat SET leases = leases + 1
+            WHERE subnet_id = NEW.subnet_id AND state = NEW.state;
+
+            -- Insert new state record if it does not exist
+            IF NOT FOUND THEN
+                INSERT INTO lease4_stat VALUES (NEW.subnet_id, NEW.state, 1);
+            END IF;
+        END IF;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+$stat_lease4_update$ LANGUAGE plpgsql;
+
+-- Create v4 update trigger
+CREATE TRIGGER stat_lease4_update
+AFTER UPDATE ON lease4
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease4_update();
+
+
+--
+-- Create the v4 delete trigger procedure
+CREATE FUNCTION proc_stat_lease4_delete () RETURNS trigger AS $stat_lease4_delete$
+BEGIN
+    IF OLD.state < 2 THEN
+        -- Decrement the state count if record exists
+        UPDATE lease4_stat SET leases = leases - 1
+        WHERE subnet_id = OLD.subnet_id AND OLD.state = state;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+$stat_lease4_delete$ LANGUAGE plpgsql;
+
+-- Create the v4 delete trigger
+CREATE TRIGGER stat_lease4_delete
+AFTER DELETE ON lease4
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease4_delete();
+
+-- Create v6 lease statistics table
+CREATE TABLE lease6_stat (
+    subnet_id BIGINT NOT NULL,
+    lease_type SMALLINT NOT NULL,
+    state INT8 NOT NULL,
+    leases BIGINT,
+    PRIMARY KEY (subnet_id, lease_type, state)
+);
+
+--
+-- Create v6 insert trigger procedure
+CREATE FUNCTION proc_stat_lease6_insert () RETURNS trigger AS $stat_lease6_insert$
+BEGIN
+    IF NEW.state < 2 THEN
+        UPDATE lease6_stat
+        SET leases = leases + 1
+        WHERE
+        subnet_id = NEW.subnet_id AND lease_type = NEW.lease_type
+        AND state = NEW.state;
+
+        IF NOT FOUND THEN
+            INSERT INTO lease6_stat
+            VALUES (NEW.subnet_id, NEW.lease_type, NEW.state, 1);
+        END IF;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+$stat_lease6_insert$ LANGUAGE plpgsql;
+
+-- Create v6 insert trigger procedure
+CREATE TRIGGER stat_lease6_insert
+AFTER INSERT ON lease6
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease6_insert();
+
+--
+-- Create v6 update trigger procedure
+CREATE FUNCTION proc_stat_lease6_update () RETURNS trigger AS $stat_lease6_update$
+BEGIN
+    IF OLD.state != NEW.state THEN
+        IF OLD.state < 2 THEN
+            -- Decrement the old state count if record exists
+            UPDATE lease6_stat SET leases = leases - 1
+            WHERE subnet_id = OLD.subnet_id AND lease_type = OLD.lease_type
+            AND state = OLD.state;
+        END IF;
+
+        IF NEW.state < 2 THEN
+            -- Increment the new state count if record exists
+            UPDATE lease6_stat SET leases = leases + 1
+            WHERE subnet_id = NEW.subnet_id AND lease_type = NEW.lease_type
+            AND state = NEW.state;
+
+            -- Insert new state record if it does not exist
+            IF NOT FOUND THEN
+                INSERT INTO lease6_stat VALUES (NEW.subnet_id, NEW.lease_type, NEW.state, 1);
+            END IF;
+        END IF;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+$stat_lease6_update$ LANGUAGE plpgsql;
+
+-- Create v6 update trigger
+CREATE TRIGGER stat_lease6_update
+AFTER UPDATE ON lease6
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease6_update();
+
+--
+-- Create the v6 delete trigger procedure
+CREATE FUNCTION proc_stat_lease6_delete() RETURNS trigger AS $stat_lease6_delete$
+BEGIN
+    IF OLD.state < 2 THEN
+        -- Decrement the state count if record exists
+        UPDATE lease6_stat SET leases = leases - 1
+        WHERE subnet_id = OLD.subnet_id AND lease_type = OLD.lease_type
+        AND OLD.state = state;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+$stat_lease6_delete$ LANGUAGE plpgsql;
+
+-- Create the v6 delete trigger
+CREATE TRIGGER stat_lease6_delete
+AFTER DELETE ON lease6
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease6_delete();
+
 -- Set 4.0 schema version.
 UPDATE schema_version
     SET version = '4', minor = '0';

src/share/database/scripts/pgsql/dhcpdb_drop.pgsql

@@ -1,4 +1,4 @@
--- Copyright (C) 2016 Internet Systems Consortium.
+-- Copyright (C) 2016-2018 Internet Systems Consortium.
 
 -- This Source Code Form is subject to the terms of the Mozilla Public
 -- License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -20,3 +20,11 @@ DROP FUNCTION IF EXISTS lease4DumpHeader();
 DROP FUNCTION IF EXISTS lease4DumpData();
 DROP FUNCTION IF EXISTS lease6DumpHeader();
 DROP FUNCTION IF EXISTS lease6DumpData();
+DROP TABLE IF EXISTS lease4_stat CASCADE;
+DROP FUNCTION IF EXISTS proc_stat_lease4_insert ();
+DROP FUNCTION IF EXISTS proc_stat_lease4_update ();
+DROP FUNCTION IF EXISTS proc_stat_lease4_delete ();
+DROP TABLE IF EXISTS lease6_stat CASCADE;
+DROP FUNCTION IF EXISTS proc_stat_lease6_insert ();
+DROP FUNCTION IF EXISTS proc_stat_lease6_update ();
+DROP FUNCTION IF EXISTS proc_stat_lease6_delete ();

src/share/database/scripts/pgsql/upgrade_3.3_to_4.0.sh.in

@@ -39,6 +39,198 @@ CREATE INDEX lease6_by_subnet_id_lease_type ON lease6 (subnet_id, lease_type);
 DROP INDEX lease6_by_iaid_subnet_id_duid;
 CREATE INDEX lease6_by_duid_iaid_subnet_id ON lease6 (duid, iaid, subnet_id);
 
+-- Create v4 lease statistics table
+CREATE TABLE lease4_stat (
+    subnet_id BIGINT NOT NULL,
+    state INT8 NOT NULL,
+    leases BIGINT,
+    PRIMARY KEY (subnet_id, state)
+);
+
+--
+-- Create v4 insert trigger procedure
+CREATE FUNCTION proc_stat_lease4_insert () RETURNS trigger AS \$stat_lease4_insert\$
+BEGIN
+    IF NEW.state < 2 THEN
+        UPDATE lease4_stat
+            SET leases = leases + 1
+            WHERE subnet_id = NEW.subnet_id AND state = NEW.state;
+
+        IF NOT FOUND THEN
+            INSERT INTO lease4_stat VALUES (new.subnet_id, new.state, 1);
+        END IF;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+\$stat_lease4_insert\$ LANGUAGE plpgsql;
+
+-- Create v4 insert trigger procedure
+CREATE TRIGGER stat_lease4_insert
+AFTER INSERT ON lease4
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease4_insert();
+
+--
+-- Create v4 update trigger procedure
+CREATE FUNCTION proc_stat_lease4_update () RETURNS trigger AS \$stat_lease4_update\$
+BEGIN
+    IF OLD.state != NEW.state THEN
+        IF OLD.state < 2 THEN
+            -- Decrement the old state count if record exists
+            UPDATE lease4_stat SET leases = leases - 1
+            WHERE subnet_id = OLD.subnet_id AND state = OLD.state;
+        END IF;
+
+        IF NEW.state < 2 THEN
+            -- Increment the new state count if record exists
+            UPDATE lease4_stat SET leases = leases + 1
+            WHERE subnet_id = NEW.subnet_id AND state = NEW.state;
+
+            -- Insert new state record if it does not exist
+            IF NOT FOUND THEN
+                INSERT INTO lease4_stat VALUES (NEW.subnet_id, NEW.state, 1);
+            END IF;
+        END IF;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+\$stat_lease4_update\$ LANGUAGE plpgsql;
+
+-- Create v4 update trigger
+CREATE TRIGGER stat_lease4_update
+AFTER UPDATE ON lease4
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease4_update();
+
+--
+-- Create the v4 delete trigger procedure
+CREATE FUNCTION proc_stat_lease4_delete () RETURNS trigger AS \$stat_lease4_delete\$
+BEGIN
+    IF OLD.state < 2 THEN
+        -- Decrement the state count if record exists
+        UPDATE lease4_stat SET leases = leases - 1
+        WHERE subnet_id = OLD.subnet_id AND OLD.state = state;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+\$stat_lease4_delete\$ LANGUAGE plpgsql;
+
+-- Create the v4 delete trigger
+CREATE TRIGGER stat_lease4_delete
+AFTER DELETE ON lease4
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease4_delete();
+
+-- Create v6 lease statistics table
+CREATE TABLE lease6_stat (
+    subnet_id BIGINT NOT NULL,
+    lease_type SMALLINT NOT NULL,
+    state INT8 NOT NULL,
+    leases BIGINT,
+    PRIMARY KEY (subnet_id, lease_type, state)
+);
+
+--
+-- Create v6 insert trigger procedure
+CREATE FUNCTION proc_stat_lease6_insert () RETURNS trigger AS \$stat_lease6_insert\$
+BEGIN
+    IF NEW.state < 2 THEN
+        UPDATE lease6_stat
+        SET leases = leases + 1
+        WHERE
+        subnet_id = NEW.subnet_id AND lease_type = NEW.lease_type
+        AND state = NEW.state;
+
+        IF NOT FOUND THEN
+            INSERT INTO lease6_stat
+            VALUES (NEW.subnet_id, NEW.lease_type, NEW.state, 1);
+        END IF;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+\$stat_lease6_insert\$ LANGUAGE plpgsql;
+
+-- Create v6 insert trigger procedure
+CREATE TRIGGER stat_lease6_insert
+AFTER INSERT ON lease6
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease6_insert();
+
+--
+-- Create v6 update trigger procedure
+CREATE FUNCTION proc_stat_lease6_update () RETURNS trigger AS \$stat_lease6_update\$
+BEGIN
+    IF OLD.state != NEW.state THEN
+        IF OLD.state < 2 THEN
+            -- Decrement the old state count if record exists
+            UPDATE lease6_stat SET leases = leases - 1
+            WHERE subnet_id = OLD.subnet_id AND lease_type = OLD.lease_type
+            AND state = OLD.state;
+        END IF;
+
+        IF NEW.state < 2 THEN
+            -- Increment the new state count if record exists
+            UPDATE lease6_stat SET leases = leases + 1
+            WHERE subnet_id = NEW.subnet_id AND lease_type = NEW.lease_type
+            AND state = NEW.state;
+
+            -- Insert new state record if it does not exist
+            IF NOT FOUND THEN
+                INSERT INTO lease6_stat VALUES (NEW.subnet_id, NEW.lease_type, NEW.state, 1);
+            END IF;
+        END IF;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+\$stat_lease6_update\$ LANGUAGE plpgsql;
+
+-- Create v6 update trigger
+CREATE TRIGGER stat_lease6_update
+AFTER UPDATE ON lease6
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease6_update();
+
+--
+-- Create the v6 delete trigger procedure
+CREATE FUNCTION proc_stat_lease6_delete() RETURNS trigger AS \$stat_lease6_delete\$
+BEGIN
+    IF OLD.state < 2 THEN
+        -- Decrement the state count if record exists
+        UPDATE lease6_stat SET leases = leases - 1
+        WHERE subnet_id = OLD.subnet_id AND lease_type = OLD.lease_type
+        AND OLD.state = state;
+    END IF;
+
+    -- Return is ignored since this is an after insert
+    RETURN NULL;
+END;
+\$stat_lease6_delete\$ LANGUAGE plpgsql;
+
+-- Create the v6 delete trigger
+CREATE TRIGGER stat_lease6_delete
+AFTER DELETE ON lease6
+    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease6_delete();
+
+-- Populate lease4_stat table based on existing leases
+-- We only care about assigned and declined states
+INSERT INTO lease4_stat (subnet_id, state, leases)
+    SELECT subnet_id, state, count(state)
+    FROM lease4 WHERE state < 2
+    GROUP BY subnet_id, state ORDER BY subnet_id;
+
+-- Populate lease6_stat table based on existing leases
+-- We only care about assigned and declined states
+INSERT INTO lease6_stat (subnet_id, lease_type, state, leases)
+    SELECT subnet_id, lease_type, state, count(state)
+    FROM lease6 WHERE state < 2
+    GROUP BY subnet_id, lease_type, state
+    ORDER BY subnet_id;
+
 -- Set 4.0 schema version.
 UPDATE schema_version
     SET version = '4', minor = '0';