What causes "Table already exists: %s.%s" in prestodb/presto?

Use CREATE TABLE IF NOT EXISTS (or check existence via SHOW TABLES / system metadata first).

prestodb/presto · error · PrestoException

HIVE_METASTORE_ERROR

HIVE_METASTORE_ERROR

Error message

Table already exists: %s.%s

What it means

During commit() of a new Iceberg table, metastore.persistTable() raised AlreadyExistsException, meaning a table with the same database.name already exists in the Hive Metastore. Presto rethrows it as a PrestoException with code HIVE_METASTORE_ERROR.

Source

Thrown at presto-iceberg/src/main/java/com/facebook/presto/iceberg/HiveTableOperations.java:321

            PrincipalPrivileges privileges = new PrincipalPrivileges(
                    ImmutableMultimap.<String, HivePrivilegeInfo>builder()
                            .put(table.getOwner(), new HivePrivilegeInfo(SELECT, true, owner, owner))
                            .put(table.getOwner(), new HivePrivilegeInfo(INSERT, true, owner, owner))
                            .put(table.getOwner(), new HivePrivilegeInfo(UPDATE, true, owner, owner))
                            .put(table.getOwner(), new HivePrivilegeInfo(DELETE, true, owner, owner))
                            .build(),
                    ImmutableMultimap.of());
            try {
                if (base == null) {
                    metastore.createTable(metastoreContext, table, privileges, emptyList());
                }
                else {
                    PartitionStatistics tableStats = metastore.getTableStatistics(metastoreContext, database, tableName);
                    metastore.persistTable(metastoreContext, database, tableName, table, privileges, () -> tableStats, useHMSLock ? ImmutableMap.of() : hmsEnvContext(base.metadataFileLocation()));
                }
            }
            catch (AlreadyExistsException e) {
                throw new PrestoException(HIVE_METASTORE_ERROR, format("Table already exists: %s.%s", database, tableName), e);
            }
            catch (CommitFailedException | CommitStateUnknownException e) {
                throw e;
            }
            catch (Throwable e) {
                if (e instanceof PrestoException && e.getCause() instanceof InvalidObjectException) {
                    throw new ValidationException(e, "Invalid Hive object for %s.%s", database, tableName);
                }
                if (e.getMessage() != null
                        && e.getMessage().contains("Table/View 'HIVE_LOCKS' does not exist")) {
                    throw new PrestoException(ICEBERG_COMMIT_ERROR,
                            "Failed to acquire locks from metastore because the underlying metastore "
                                    + "table 'HIVE_LOCKS' does not exist. This can occur when using an embedded metastore which does not "
                                    + "support transactions. To fix this use an alternative metastore.",
                            e);
                }
                CommitStatus commitStatus;
                if (e.getMessage() != null

View on GitHub (pinned to 55bb57d202)

Solutions

Use CREATE TABLE IF NOT EXISTS (or check existence via SHOW TABLES / system metadata first).
Drop or rename the existing table if it is stale/unwanted.
Serialize table-creation logic in deployment scripts to avoid concurrent creates.

Example fix

-- before
CREATE TABLE iceberg.db.events (...) ;
-- after
CREATE TABLE IF NOT EXISTS iceberg.db.events (...);

Defensive patterns

Strategy: validation

Validate before calling

boolean exists = metadata.getSession().getMetadata().getTableHandle(session, tableName) != null;
if (exists) throw new IllegalStateException("Table exists: " + tableName);

Try / catch

try { createTable(...); }
catch (PrestoException e) { if (e.getErrorCode() == HIVE_METASTORE_ERROR.toErrorCode()) { /* handle existing table */ } }

Prevention

Use CREATE TABLE IF NOT EXISTS in idempotent scripts.
Check SHOW TABLES / information_schema before create.
Guard concurrent deployments from creating the same table.

When it happens

Trigger: Calling CREATE TABLE / CREATE TABLE AS against an Iceberg catalog when the target table already exists in HMS (e.g. created concurrently or left over from a previous run).

Common situations: Idempotency-less CI/CD or migration scripts run twice; race between two sessions creating the same table; inconsistent catalogs where the Iceberg metadata files are absent but the HMS entry exists.

Related errors

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/a0a5462cca2a18f2. Report an issue: GitHub.