Changeset: 35653312f9cb for monetdb-java
URL: https://dev.monetdb.org/hg/monetdb-java/rev/35653312f9cb
Modified Files:
src/main/java/org/monetdb/jdbc/MonetConnection.java
Branch: default
Log Message:
Optimise check on existence of specific tables. Instead of doing a query per
table name, combine them in one query.
diffs (64 lines):
diff --git a/src/main/java/org/monetdb/jdbc/MonetConnection.java
b/src/main/java/org/monetdb/jdbc/MonetConnection.java
--- a/src/main/java/org/monetdb/jdbc/MonetConnection.java
+++ b/src/main/java/org/monetdb/jdbc/MonetConnection.java
@@ -1991,7 +1991,7 @@ public class MonetConnection
*/
boolean privilege_codesTableExists() {
if (!queriedPrivilege_codesTable) {
- hasPrivilege_codesTable =
existsSysTable("privilege_codes");
+ querySysTable();
queriedPrivilege_codesTable = true; // set flag, so
the querying is done only at first invocation.
}
return hasPrivilege_codesTable;
@@ -2008,7 +2008,7 @@ public class MonetConnection
*/
boolean commentsTableExists() {
if (!queriedCommentsTable) {
- hasCommentsTable = existsSysTable("comments");
+ querySysTable();
queriedCommentsTable = true; // set flag, so the
querying is done only at first invocation.
}
return hasCommentsTable;
@@ -2018,18 +2018,27 @@ public class MonetConnection
/**
* Internal utility method to query the server to find out if it has a
specific system table sys.<tablename>.
*/
- private boolean existsSysTable(final String tablename) {
- boolean exists = false;
+ private void querySysTable() {
Statement stmt = null;
ResultSet rs = null;
try {
stmt = createStatement();
if (stmt != null) {
- rs = stmt.executeQuery("SELECT id FROM
sys._tables WHERE name = '"
- + tablename
- + "' AND schema_id IN
(SELECT id FROM sys.schemas WHERE name = 'sys')");
+ rs = stmt.executeQuery("SELECT name FROM
sys._tables WHERE name in ('privilege_codes', 'comments')"
+ + " AND schema_id IN
(SELECT id FROM sys.schemas WHERE name = 'sys')");
if (rs != null) {
- exists = rs.next(); // if a row is
available it exists, else not
+ while (rs.next()) {
+ String name = rs.getString(1);
+ // for debug:
System.out.println("querySysTable() retrieved name: " + name);
+ if ("comments".equals(name)) {
+ hasCommentsTable = true;
+ queriedCommentsTable =
true;
+ } else
+ if
("privilege_codes".equals(name)) {
+ hasPrivilege_codesTable
= true;
+
queriedPrivilege_codesTable = true;
+ }
+ }
}
}
} catch (SQLException se) {
@@ -2037,8 +2046,6 @@ public class MonetConnection
} finally {
closeResultsetStatement(rs, stmt);
}
- // for debug: System.out.println("testTableExists(" + tablename
+ ") returns: " + exists);
- return exists;
}
/**
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