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Keeping PostgreSQL prepared statements in thread local variables #13

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Keeping PostgreSQL prepared statements in thread local variables #13

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67 changes: 35 additions & 32 deletions src/main/java/com/yugabyte/sample/apps/SqlInserts.java
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.List;

Expand Down Expand Up @@ -50,13 +51,10 @@ public class SqlInserts extends AppBase {
private static final String DEFAULT_TABLE_NAME = "PostgresqlKeyValue";

// The shared prepared select statement for fetching the data.
private volatile PreparedStatement preparedSelect = null;
private ThreadLocal<PreparedStatement> preparedSelect = new ThreadLocal<PreparedStatement>();

// The shared prepared insert statement for inserting the data.
private volatile PreparedStatement preparedInsert = null;

// Lock for initializing prepared statement objects.
private static final Object prepareInitLock = new Object();
private ThreadLocal<PreparedStatement> preparedInsert = new ThreadLocal<PreparedStatement>();

public SqlInserts() {
buffer = new byte[appConfig.valueSize];
Expand Down Expand Up @@ -91,11 +89,34 @@ public String getTableName() {
}

private PreparedStatement getPreparedSelect() throws Exception {
if (preparedSelect == null) {
preparedSelect = getPostgresConnection().prepareStatement(
String.format("SELECT k, v FROM %s WHERE k = ?;", getTableName()));
if (preparedSelect.get() == null) {
preparedSelect.set(
getPostgresConnection().prepareStatement(
String.format("SELECT k, v FROM %s WHERE k = ?;", getTableName())));
}
return preparedSelect;
return preparedSelect.get();
}

private int readKey(Key key) throws Exception {
PreparedStatement statement = getPreparedSelect();
statement.setString(1, key.asString());
try (ResultSet rs = statement.executeQuery()) {
if (!rs.next()) {
LOG.error("Read key: " + key.asString() + " expected 1 row in result, got 0");
return 0;
}

if (!key.asString().equals(rs.getString("k"))) {
LOG.error("Read key: " + key.asString() + ", got " + rs.getString("k"));
}
LOG.debug("Read key: " + key.toString());

if (rs.next()) {
LOG.error("Read key: " + key.asString() + " expected 1 row in result, got more");
return 0;
}
}
return 1;
}

@Override
Expand All @@ -107,37 +128,19 @@ public long doRead() {
}

try {
PreparedStatement statement = getPreparedSelect();
statement.setString(1, key.asString());
try (ResultSet rs = statement.executeQuery()) {
if (!rs.next()) {
LOG.error("Read key: " + key.asString() + " expected 1 row in result, got 0");
return 0;
}

if (!key.asString().equals(rs.getString("k"))) {
LOG.error("Read key: " + key.asString() + ", got " + rs.getString("k"));
}
LOG.debug("Read key: " + key.toString());

if (rs.next()) {
LOG.error("Read key: " + key.asString() + " expected 1 row in result, got more");
return 0;
}
}
return readKey(key);
} catch (Exception e) {
LOG.fatal("Failed reading value: " + key.getValueStr(), e);
return 0;
}
return 1;
}

private PreparedStatement getPreparedInsert() throws Exception {
if (preparedInsert == null) {
preparedInsert = getPostgresConnection().prepareStatement(
String.format("INSERT INTO %s (k, v) VALUES (?, ?);", getTableName()));
if (preparedInsert.get() == null) {
preparedInsert.set(getPostgresConnection().prepareStatement(
String.format("INSERT INTO %s (k, v) VALUES (?, ?);", getTableName())));
}
return preparedInsert;
return preparedInsert.get();
}

@Override
Expand Down