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This page describes newly identified limitations in the CockroachDB v21.2.8 release likewise every bit unresolved limitations identified in earlier releases.

New limitations

CockroachDB does not properly optimize some left and anti joins with GIN indexes

Left joins and anti joins involving JSONB, Array, or spatial-typed columns with a multi-column or partitioned GIN alphabetize will not take advantage of the index if the prefix columns of the index are unconstrained, or if they are constrained to multiple, constant values.

To piece of work around this limitation, make sure that the prefix columns of the index are either constrained to single constant values, or are part of an equality condition with an input column (due east.1000., col1 = col2, where col1 is a prefix column and col2 is an input column).

For case, suppose you accept the following multi-region database and tables:

                          CREATE              DATABASE              multi_region_test_db              PRIMARY              REGION              "europe-west1"              REGIONS              "us-west1"              ,              "us-east1"              SURVIVE              REGION              FAILURE              ;              USE              multi_region_test_db              ;              CREATE              TABLE              t1              (              k              INT              PRIMARY              Key              ,              geom              GEOMETRY              );              CREATE              TABLE              t2              (              one thousand              INT              PRIMARY              KEY              ,              geom              GEOMETRY              ,              INVERTED              INDEX              geom_idx              (              geom              )              )              LOCALITY              REGIONAL              By              ROW              ;                      

And you insert some data into the tables:

                          INSERT              INTO              t1              SELECT              generate_series              (              1              ,              1000              ),              'Betoken(1.0 1.0)'              ;              INSERT              INTO              t2              (              crdb_region              ,              k              ,              geom              )              SELECT              'us-east1'              ,              generate_series              (              1              ,              1000              ),              'Indicate(1.0 1.0)'              ;              INSERT              INTO              t2              (              crdb_region              ,              k              ,              geom              )              SELECT              'us-west1'              ,              generate_series              (              1001              ,              2000              ),              'POINT(2.0 2.0)'              ;              INSERT              INTO              t2              (              crdb_region              ,              k              ,              geom              )              SELECT              'europe-west1'              ,              generate_series              (              2001              ,              3000              ),              'POINT(3.0 3.0)'              ;                      

If you lot attempt a left join between t1 and t2 on only the geometry columns, CockroachDB volition not be able to program an inverted join:

            > Explain SELECT * FROM t1 LEFT JOIN t2 ON st_contains(t1.geom, t2.geom);                 info ------------------------------------   distribution: full   vectorized: true    • cantankerous join (right outer)   │ pred: st_contains(geom, geom)   │   ├── • scan   │     estimated row count: 3,000   │     tabular array: t2@primary   │     spans: Full SCAN   │   └── • scan         estimated row count: ane,000         table: t1@primary         spans: Total SCAN (fifteen rows)                      

However, if you constrain the crdb_region column to a unmarried value, CockroachDB tin can plan an inverted join:

            > EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON st_contains(t1.geom, t2.geom) AND t2.crdb_region = 'u.s.-east1';                        info --------------------------------------------------   distribution: full   vectorized: true    • lookup join (left outer)   │ table: t2@primary   │ equality: (crdb_region, k) = (crdb_region,k)   │ equality cols are key   │ pred: st_contains(geom, geom)   │   └── • inverted bring together (left outer)       │ table: t2@geom_idx       │       └── • render           │           └── • scan                 estimated row count: 1,000                 tabular array: t1@master                 spans: Full SCAN (18 rows)                      

If you lot do not know which region to utilise, you can combine queries with UNION ALL:

            > EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON st_contains(t1.geom, t2.geom) AND t2.crdb_region = 'us-east1' Spousal relationship ALL SELECT * FROM t1 LEFT JOIN t2 ON st_contains(t1.geom, t2.geom) AND t2.crdb_region = 'united states of america-west1' UNION ALL SELECT * FROM t1 LEFT Bring together t2 ON st_contains(t1.geom, t2.geom) AND t2.crdb_region = 'europe-west1';                            info ----------------------------------------------------------   distribution: total   vectorized: true    • union all   │   ├── • union all   │   │   │   ├── • lookup join (left outer)   │   │   │ table: t2@primary   │   │   │ equality: (crdb_region, k) = (crdb_region,k)   │   │   │ equality cols are key   │   │   │ pred: st_contains(geom, geom)   │   │   │   │   │   └── • inverted join (left outer)   │   │       │ table: t2@geom_idx   │   │       │   │   │       └── • render   │   │           │   │   │           └── • browse   │   │                 estimated row count: ane,000   │   │                 table: t1@principal   │   │                 spans: FULL SCAN   │   │   │   └── • lookup join (left outer)   │       │ table: t2@primary   │       │ equality: (crdb_region, k) = (crdb_region,thousand)   │       │ equality cols are key   │       │ pred: st_contains(geom, geom)   │       │   │       └── • inverted join (left outer)   │           │ table: t2@geom_idx   │           │   │           └── • render   │               │   │               └── • scan   │                     estimated row count: 1,000   │                     tabular array: t1@chief   │                     spans: Full Scan   │   └── • lookup join (left outer)       │ tabular array: t2@primary       │ equality: (crdb_region, k) = (crdb_region,yard)       │ equality cols are key       │ pred: st_contains(geom, geom)       │       └── • inverted bring together (left outer)           │ table: t2@geom_idx           │           └── • return               │               └── • scan                     estimated row count: 1,000                     table: t1@chief                     spans: FULL Browse (54 rows)                      

Tracking GitHub Result

Using RESTORE with multi-region table localities

• Restoring GLOBAL and REGIONAL By TABLE tables into a not-multi-region database is not supported. Tracking GitHub Issue

• REGIONAL By Tabular array and REGIONAL BY ROW tables tin be restored only if the regions of the backed-up table friction match those of the target database. All of the post-obit must exist true for RESTORE to exist successful:

  • The regions of the source database and the regions of the destination database have the same set of regions.
  • The regions were added to each of the databases in the same order.
  • The databases take the same master region.

  The following case would be considered as having mismatched regions considering the database regions were not added in the same club and the chief regions do not match.

  Running on the source database:

                                    ALTER                  DATABASE                  source_database                  Set up                  PRIMARY                  REGION                  "us-east1"                  ;                              

                                    ALTER                  DATABASE                  source_database                  ADD                  region                  "usa-west1"                  ;                              

  Running on the destination database:

                                    ALTER                  DATABASE                  destination_database                  Fix                  Principal                  REGION                  "u.s.-west1"                  ;                              

                                    Modify                  DATABASE                  destination_database                  Add together                  region                  "us-east1"                  ;                              

  In addition, the following scenario has mismatched regions betwixt the databases since the regions were non added to the database in the aforementioned gild.

  Running on the source database:

                                    Modify                  DATABASE                  source_database                  Set                  PRIMARY                  REGION                  "us-east1"                  ;                              

                                    ALTER                  DATABASE                  source_database                  ADD                  region                  "the states-west1"                  ;                              

  Running on the destination database:

                                    Change                  DATABASE                  destination_database                  SET                  PRIMARY                  REGION                  "u.s.-west1"                  ;                              

                                    ALTER                  DATABASE                  destination_database                  Add                  region                  "the states-east1"                  ;                              

                                    ALTER                  DATABASE                  destination_database                  SET                  Principal                  REGION                  "u.s.-east1"                  ;                              

Tracking GitHub Effect

SET does non ROLLBACK in a transaction

SET does not properly apply ROLLBACK within a transaction. For instance, in the post-obit transaction, showing the Time ZONE variable does not return two as expected after the rollback:

                          Prepare              TIME              ZONE              +              2              ;              BEGIN              ;              SET              Fourth dimension              ZONE              +              3              ;              ROLLBACK              ;              SHOW              TIME              ZONE              ;                      

Tracking GitHub Consequence

JSONB/JSON comparison operators are not implemented

CockroachDB does not back up using comparison operators (such as < or >) on JSONB elements. For example, the following query does non piece of work and returns an error:

                          SELECT              '{"a": 1}'              ::              JSONB              ->              'a'              <              '{"b": ii}'              ::              JSONB              ->              'b'              ;                      

            ERROR: unsupported comparison operator: <jsonb> < <jsonb> SQLSTATE: 22023                      

Tracking GitHub Issue

Locality-optimized search only works for queries selecting a limited number of records

• Locality optimized search works only for queries selecting a limited number of records (up to 100,000 unique keys). Information technology does not piece of work with LIMIT clauses. Tracking GitHub Issue

Expression indexes cannot reference computed columns

CockroachDB does not let expression indexes to reference computed columns.

Tracking GitHub Issue

Cannot refresh materialized views inside explicit transactions

CockroachDB cannot refresh materialized views inside explicit transactions. Trying to refresh a materialized view inside an explicit transaction volition consequence in an fault, as shown below.

1. Starting time, showtime cockroach demo with the sample bank data fix:

2. Create the materialized view described in Materialized views → Usage.

3. Start a new multi-statement transaction with BEGIN TRANSACTION:

4. Inside the open transaction, attempt to refresh the view every bit shown below. This will effect in an error.

                                     REFRESH                  MATERIALIZED                  VIEW                  overdrawn_accounts                  ;                              

                   Mistake: cannot refresh view in an explicit transaction SQLSTATE: 25000                              

Tracking GitHub Event

CockroachDB cannot plan locality optimized searches that use partitioned unique indexes on virtual computed columns

• Locality optimized search does not work for queries that use partitioned unique indexes on virtual computed columns. A workaround for computed columns is to make the virtual computed column a stored computed column. Locality optimized search does not work for queries that use partitioned unique expression indexes. Tracking GitHub Issue

Expressions as ON Conflict targets are not supported

CockroachDB does not support expressions as ON Conflict targets. This means that unique expression indexes cannot be selected as arbiters for INSERT .. ON CONFLICT statements. For example:

                          CREATE              TABLE              t              (              a              INT              ,              b              INT              ,              UNIQUE              INDEX              ((              a              +              b              )));                      

                          INSERT              INTO              t              VALUES              (              1              ,              2              )              ON              Conflict              ((              a              +              b              ))              DO              NOTHING              ;                      

            invalid syntax: statement ignored: at or well-nigh "(": syntax fault SQLSTATE: 42601 Particular: source SQL: INSERT INTO t VALUES (1, 2) ON CONFLICT ((a + b)) Practise NOTHING                                     ^ HINT: try \h INSERT                      

                          INSERT              INTO              t              VALUES              (              1              ,              2              )              ON              CONFLICT              ((              a              +              b              ))              Practice              UPDATE              Ready              a              =              10              ;                      

            invalid syntax: argument ignored: at or nearly "(": syntax error SQLSTATE: 42601 DETAIL: source SQL: INSERT INTO t VALUES (i, ii) ON CONFLICT ((a + b)) DO UPDATE Fix a = x                                     ^ HINT: attempt \h INSERT                      

Tracking GitHub Issue

Unresolved limitations

Optimizer stale statistics deletion when columns are dropped

• When a cavalcade is dropped from a multi-column index, the optimizer volition not collect new statistics for the deleted column. However, the optimizer never deletes the old multi-cavalcade statistics. This can cause a buildup of statistics in arrangement.table_statistics leading the optimizer to use stale statistics, which could issue in sub-optimal plans. To workaround this issue and avoid these scenarios, explicitly delete those statistics from the system.table_statistics tabular array.

  Tracking GitHub Issue

• Single-column statistics are non deleted when columns are dropped, which could crusade pocket-size performance issues.

  Tracking GitHub Issue

Automatic statistics refresher may not refresh afterwards upgrade

The automated statistics refresher automatically checks whether information technology needs to refresh statistics for every tabular array in the database upon startup of each node in the cluster. If statistics for a tabular array have not been refreshed in a while, this will trigger collection of statistics for that table. If statistics take been refreshed recently, it will not force a refresh. Every bit a result, the automatic statistics refresher does not necessarily perform a refresh of statistics after an upgrade. This could crusade a trouble, for example, if the upgrade moves from a version without histograms to a version with histograms. To refresh statistics manually, employ CREATE STATISTICS.

Tracking GitHub Result

Differences in syntax and behavior between CockroachDB and PostgreSQL

CockroachDB supports the PostgreSQL wire protocol and the majority of its syntax. Nevertheless, CockroachDB does not support some of the PostgreSQL features or behaves differently from PostgreSQL because non all features can be hands implemented in a distributed system.

For a listing of known differences in syntax and beliefs between CockroachDB and PostgreSQL, run into Features that differ from PostgreSQL.

Multiple arbiter indexes for INSERT ON CONFLICT Do UPDATE

CockroachDB does not currently support multiple arbiter indexes for INSERT ON CONFLICT DO UPDATE, and will return an error if there are multiple unique or exclusion constraints matching the ON CONFLICT DO UPDATE specification.

Tracking GitHub Issue

IMPORT into a table with partial indexes

CockroachDB does not currently support IMPORTs into tables with partial indexes.

To work effectually this limitation:

1. Driblet any partial indexes defined on the table.
2. Perform the IMPORT.
3. Recreate the partial indexes.

If y'all are performing an IMPORT of a PGDUMP with partial indexes:

1. Drib the partial indexes on the PostgreSQL server.
2. Recreate the PGDUMP.
3. IMPORT the PGDUMP.
4. Add fractional indexes on the CockroachDB server.

Tracking GitHub Upshot

Historical reads on restored objects

An object's historical data is not preserved upon RESTORE. This means that if an Every bit OF SYSTEM TIME query is issued on a restored object, the query volition fail or the response will exist incorrect because there is no historical information to query.

Tracking GitHub Event

Spatial support limitations

CockroachDB supports efficiently storing and querying spatial data, with the post-obit limitations:

• Not all PostGIS spatial functions are supported.

  Tracking GitHub Issue

• The AddGeometryColumn spatial part just allows constant arguments.

  Tracking GitHub Effect

• The AddGeometryColumn spatial function just allows the true value for its use_typmod parameter.

  Tracking GitHub Effect

• CockroachDB does not back up the @ operator. Instead of using @ in spatial expressions, we recommend using the inverse, with ~. For instance, instead of a @ b, use b ~ a.

  Tracking GitHub Issue

• CockroachDB does not yet back up INSERTsouthward into the spatial_ref_sys tabular array. This limitation also blocks the ogr2ogr -f PostgreSQL file conversion command.

  Tracking GitHub Issue

• CockroachDB does not yet back up DECLARE CURSOR, which prevents the ogr2ogr conversion tool from exporting from CockroachDB to sure formats and prevents QGIS from working with CockroachDB. To piece of work around this limitation, export data first to CSV or GeoJSON format.

  Tracking GitHub Issue

• CockroachDB does non yet support Triangle or TIN spatial shapes.

  Tracking GitHub Upshot

• CockroachDB does not withal support Curve, MultiCurve, or CircularString spatial shapes.

  Tracking GitHub Issue

• CockroachDB does not yet support k-nearest neighbors.

  Tracking GitHub Result

• CockroachDB does non back up using schema name prefixes to refer to data types with type modifiers (e.m., public.geometry(linestring, 4326)). Instead, use fully-unqualified names to refer to data types with type modifiers (e.g., geometry(linestring,4326)).

  Note that, in IMPORT PGDUMP output, GEOMETRY and GEOGRAPHY information type names are prefixed by public.. If the type has a type modifier, yous must remove the public. from the type proper noun in order for the statements to work in CockroachDB.

  Tracking GitHub Consequence

Subqueries in SET statements

It is not currently possible to use a subquery in a Fix or SET CLUSTER SETTING statement. For example:

                          >              Set              application_name              =              (              SELECT              'a'              ||              'b'              );                      

            Mistake: invalid value for parameter "application_name": "(SELECT 'a' || 'b')" SQLSTATE: 22023 DETAIL: subqueries are not allowed in Set                      

Tracking GitHub Result

Enterprise BACKUP does not capture database/table/column comments

The COMMENT ON statement assembly comments to databases, tables, or columns. Yet, the internal tabular array (system.comments) in which these comments are stored is not captured by a Backup of a table or database.

As a workaround, take a cluster backup instead, as the system.comments table is included in cluster backups.

Tracking GitHub Issue

Modify data capture

Modify information capture (CDC) provides efficient, distributed, row-level change feeds into Apache Kafka for downstream processing such every bit reporting, caching, or full-text indexing. Information technology has the following known limitations:

• Changefeeds just work on tables with a unmarried column family (which is the default for new tables). Tracking GitHub Issue
• Changefeeds cannot be backed up or restored. Tracking GitHub Result
• Changefeeds cannot be altered. To modify, cancel the changefeed and create a new one with updated settings from where it left off. Tracking GitHub Issue
• Changefeed target options are limited to tables. Tracking GitHub Result
• Using a cloud storage sink only works with JSON and emits newline-delimited json files. Tracking GitHub Consequence
• Webhook sinks just support HTTPS. Employ the insecure_tls_skip_verify parameter when testing to disable certificate verification; however, this still requires HTTPS and certificates. Tracking GitHub Issue
• Currently, webhook sinks only have support for emitting JSON. Tracking GitHub Issue
• At that place is no concurrency configurability for webhook sinks. Tracking GitHub Issue
• Enterprise changefeeds are currently disabled for CockroachDB Serverless (beta) clusters. Core changefeeds are enabled. Tracking GitHub Result
  
• Changefeeds volition emit Nix values for VIRTUAL computed columns and not the cavalcade'south computed value. Tracking GitHub Event

DB Console may become inaccessible for secure clusters

Accessing the DB Console for a secure cluster now requires login information (i.e., username and password). This login information is stored in a system table that is replicated like other information in the cluster. If a majority of the nodes with the replicas of the arrangement table data go down, users will exist locked out of the DB Console.

AS OF System Time in SELECT statements

AS OF SYSTEM Fourth dimension can merely exist used in a acme-level SELECT statement. That is, we exercise not support statements similar INSERT INTO t SELECT * FROM t2 Equally OF Arrangement TIME <time> or two subselects in the same statement with differing As OF SYSTEM TIME arguments.

Tracking GitHub Result

Large index keys tin impair performance

The utilise of tables with very large master or secondary alphabetize keys (>32KB) tin consequence in excessive memory usage. Specifically, if the main or secondary index key is larger than 32KB the default indexing scheme for storage engine SSTables breaks down and causes the index to be excessively big. The index is pinned in memory by default for operation.

To work around this consequence, we recommend limiting the size of primary and secondary keys to 4KB, which you must account for manually. Annotation that most columns are 8B (exceptions being STRING and JSON), which still allows for very complex key structures.

Tracking GitHub Issue

Using Similar...ESCAPE in WHERE and HAVING constraints

CockroachDB tries to optimize well-nigh comparisons operators in WHERE and HAVING clauses into constraints on SQL indexes by simply accessing selected rows. This is washed for Like clauses when a mutual prefix for all selected rows can be determined in the search pattern (eastward.1000., ... LIKE 'Joe%'). Even so, this optimization is not yet available if the ESCAPE keyword is likewise used.

Tracking GitHub Issue

TRUNCATE does not deport like DELETE

TRUNCATE is not a DML argument, merely instead works equally a DDL statement. Its limitations are the same as other DDL statements, which are outlined in Online Schema Changes: Limitations

Tracking GitHub Issue

Ordering tables by JSONB/JSON-typed columns

CockroachDB does non currently key-encode JSON values. Equally a result, tables cannot exist ordered by JSONB/JSON-typed columns.

Tracking GitHub Issue

Current sequence value non checked when updating min/max value

Altering the minimum or maximum value of a serial does not check the current value of a series. This means that it is possible to silently set the maximum to a value less than, or a minimum value greater than, the electric current value.

Tracking GitHub Event

Using default_int_size session variable in batch of statements

When setting the default_int_size session variable in a batch of statements such as SET default_int_size='int4'; SELECT i::IN, the default_int_size variable volition not take affect until the next statement. This happens because argument parsing takes identify asynchronously from statement execution.

As a workaround, set default_int_size via your database driver, or ensure that Ready default_int_size is in its own statement.

Tracking GitHub Issue

COPY FROM statements are not supported in the CockroachDB SQL vanquish

The built-in SQL shell provided with CockroachDB (cockroach sql / cockroach demo) does not currently support importing data with the Copy statement.

To load data into CockroachDB, we recommend that you lot apply an IMPORT. If you must utilise a COPY argument, you can result the statement from the psql client control provided with PostgreSQL, or from another tertiary-party client.

Tracking GitHub Issue

Copy syntax not supported past CockroachDB

CockroachDB does not yet support the post-obit Re-create syntax:

• Copy ... TO. To copy information from a CockroachDB cluster to a file, use an Export statement.

  Tracking GitHub Outcome

• COPY ... FROM ... WHERE <expr>

  Tracking GitHub Issue

Import with a high amount of disk contention

IMPORT tin sometimes fail with a "context canceled" error, or tin can restart itself many times without e'er finishing. If this is happening, it is likely due to a high corporeality of disk contention. This can be mitigated by setting the kv.bulk_io_write.max_rate cluster setting to a value beneath your max disk write speed. For example, to set it to 10MB/south, execute:

                          >              SET              CLUSTER              SETTING              kv              .              bulk_io_write              .              max_rate              =              '10MB'              ;                      

Placeholders in PARTITION By

When defining a tabular array partition, either during table creation or table alteration, it is not possible to use placeholders in the Segmentation BY clause.

Tracking GitHub Effect

Calculation a column with sequence-based DEFAULT values

It is currently not possible to add a column to a table when the column uses a sequence as the DEFAULT value, for instance:

                          >              CREATE              TABLE              t              (              10              INT              );                      

                          >              INSERT              INTO              t              (              ten              )              VALUES              (              1              ),              (              2              ),              (              3              );                      

                          >              ALTER              TABLE              t              Add together              Column              y              INT              DEFAULT              nextval              (              'southward'              );                      

            Fault: nextval(): unimplemented: cannot evaluate scalar expressions containing sequence operations in this context SQLSTATE: 0A000                      

Tracking GitHub Upshot

Available capacity metric in the DB Panel

If y'all are testing your deployment locally with multiple CockroachDB nodes running on a single machine (this is not recommended in production), y'all must explicitly ready the store size per node in order to display the correct chapters. Otherwise, the machine's actual disk capacity will exist counted as a split up store for each node, thus inflating the computed chapters.

Schema changes within transactions

Within a unmarried transaction:

• DDL statements cannot be mixed with DML statements. Equally a workaround, y'all tin can split the statements into separate transactions. For more details, encounter examples of unsupported statements.
• As of version v2.ane, you lot can run schema changes inside the same transaction every bit a CREATE Tabular array argument. For more information, see this case.
• A CREATE Table argument containing FOREIGN Cardinal clauses cannot be followed by statements that reference the new table.
• Database, schema, table, and user-defined type names cannot be reused. For example, you cannot drop a tabular array named a so create (or rename) a unlike table with the name a. Similarly, you cannot rename a database named a to b then create (or rename) a different database with the name a. As a workaround, split RENAME TO, DROP, and CREATE statements that reuse object names into separate transactions.
• Schema change DDL statements within a multi-statement transaction tin fail while other statements succeed.
• As of v19.1, some schema changes can be used in combination in a unmarried Change TABLE statement. For a listing of commands that can be combined, meet Change TABLE. For a demonstration, see Add together and rename columns atomically.
• DROP Cavalcade tin event in data loss if one of the other schema changes in the transaction fails or is canceled. To work around this, motion the DROP COLUMN statement to its own explicit transaction or run it in a unmarried statement outside the existing transaction.

Notation:

If a schema change inside a transaction fails, manual intervention may be needed to determine which has failed. After determining which schema change(s) failed, y'all can then retry the schema changes.

Schema modify DDL statements within a multi-statement transaction can neglect while other statements succeed

Schema change DDL statements that run inside a multi-statement transaction with non-DDL statements can fail at COMMIT time, fifty-fifty if other statements in the transaction succeed. This leaves such transactions in a "partially committed, partially aborted" country that may crave manual intervention to determine whether the DDL statements succeeded.

If such a failure occurs, CockroachDB volition emit a new CockroachDB-specific mistake lawmaking, XXA00, and the following error message:

            transaction committed simply schema modify aborted with mistake: <description of error> HINT: Some of the not-DDL statements may have committed successfully, but some of the DDL statement(s) failed. Manual inspection may be required to make up one's mind the actual state of the database.                      

Note:

This limitation exists in versions of CockroachDB prior to xix.2. In these older versions, CockroachDB returned the Postgres mistake code 40003, "statement completion unknown".

Warning:

If you must execute schema change DDL statements within a multi-statement transaction, we strongly recommend checking for this error code and handling information technology appropriately every time you lot execute such transactions.

This error will occur in various scenarios, including but not limited to:

• Creating a unique index fails because values aren't unique.
• The evaluation of a computed value fails.
• Adding a constraint (or a column with a constraint) fails because the constraint is violated for the default/computed values in the column.

To see an instance of this error, first by creating the post-obit table.

                          CREATE              Table              T              (              x              INT              );              INSERT              INTO              T              (              x              )              VALUES              (              ane              ),              (              2              ),              (              3              );                      

Then, enter the post-obit multi-statement transaction, which will trigger the mistake.

                          Brainstorm              ;              ALTER              Table              t              ADD              CONSTRAINT              unique_x              UNIQUE              (              x              );              INSERT              INTO              T              (              x              )              VALUES              (              3              );              COMMIT              ;                      

            pq: transaction committed but schema change aborted with error: (23505): indistinguishable fundamental value (x)=(three) violates unique constraint "unique_x" HINT: Some of the not-DDL statements may have committed successfully, but some of the DDL statement(s) failed. Manual inspection may be required to determine the bodily state of the database.                      

In this example, the INSERT statement committed, but the Change TABLE statement adding a UNIQUE constraint failed. Nosotros tin can verify this past looking at the data in tabular array t and seeing that the boosted not-unique value 3 was successfully inserted.

Schema changes betwixt executions of prepared statements

When the schema of a tabular array targeted by a prepared statement changes earlier the prepared statement is executed, CockroachDB allows the prepared statement to return results based on the changed table schema, for example:

                          >              CREATE              Tabular array              users              (              id              INT              PRIMARY              Primal              );                      

                          >              PREPARE              prep1              AS              SELECT              *              FROM              users              ;                      

                          >              Modify              TABLE              users              Add together              Column              proper noun              String              ;                      

                          >              INSERT              INTO              users              VALUES              (              1              ,              'Max Roach'              );                      

                          id |   name -----+------------    1 | Max Roach (1 row)                      

Information technology's therefore recommended to non use SELECT * in queries that volition be repeated, via prepared statements or otherwise.

Besides, a prepared INSERT, UPSERT, or DELETE argument acts inconsistently when the schema of the tabular array existence written to is changed before the prepared argument is executed:

• If the number of columns has increased, the prepared statement returns an error simply notwithstanding writes the data.
• If the number of columns remains the aforementioned but the types accept inverse, the prepared statement writes the data and does not return an error.

Size limits on argument input from SQL clients

CockroachDB imposes a hard limit of 16MiB on the data input for a single argument passed to CockroachDB from a client (including the SQL shell). Nosotros practise not recommend attempting to execute statements from clients with large input.

Using \| to perform a large input in the SQL vanquish

In the built-in SQL shell, using the \| operator to perform a big number of inputs from a file tin can crusade the server to shut the connection. This is because \| sends the unabridged file every bit a unmarried query to the server, which can exceed the upper bound on the size of a packet the server can accept from any client (16MB).

As a workaround, execute the file from the control line with true cat data.sql | cockroach sql instead of from inside the interactive beat.

New values generated by DEFAULT expressions during Alter TABLE Add together Cavalcade

When executing an Alter TABLE Add together Cavalcade statement with a DEFAULT expression, new values generated:

• use the default search path regardless of the search path configured in the current session via Gear up SEARCH_PATH.
• use the UTC fourth dimension zone regardless of the fourth dimension zone configured in the current session via Gear up Time ZONE.
• have no default database regardless of the default database configured in the current session via SET DATABASE, and then you must specify the database of any tables they reference.
• utilize the transaction timestamp for the statement_timestamp() function regardless of the time at which the Alter statement was issued.

Load-based charter rebalancing in uneven latency deployments

When nodes are started with the --locality flag, CockroachDB attempts to place the replica lease holder (the replica that customer requests are forwarded to) on the node closest to the source of the request. This means as customer requests move geographically, so likewise does the replica lease holder.

Even so, you might see increased latency caused by a consistently high rate of lease transfers between datacenters in the following instance:

• Your cluster runs in datacenters which are very different distances abroad from each other.
• Each node was started with a single tier of --locality, due east.1000., --locality=datacenter=a.
• Well-nigh client requests become sent to a single datacenter because that's where all your application traffic is.

To detect if this is happening, open the DB Console, select the Queues dashboard, hover over the Replication Queue graph, and cheque the Leases Transferred / 2d data signal. If the value is consistently larger than 0, you lot should consider stopping and restarting each node with boosted tiers of locality to ameliorate request latency.

For example, let's say that latency is 10ms from nodes in datacenter A to nodes in datacenter B but is 100ms from nodes in datacenter A to nodes in datacenter C. To ensure A'due south and B'due south relative proximity is factored into lease holder rebalancing, yous could restart the nodes in datacenter A and B with a common region, --locality=region=foo,datacenter=a and --locality=region=foo,datacenter=b, while restarting nodes in datacenter C with a different region, --locality=region=bar,datacenter=c.

Overload resolution for collated strings

Many cord operations are not properly overloaded for collated strings, for instance:

                          >              SELECT              'string1'              ||              'string2'              ;                      

                          ?column? ------------------   string1string2 (1 row)                      

                          >              SELECT              (              'string1'              collate              en              )              ||              (              'string2'              collate              en              );                      

            pq: unsupported binary operator: <collatedstring{en}> || <collatedstring{en}>                      

Tracking GitHub Event

Max size of a single column family

When creating or updating a row, if the combined size of all values in a single column family exceeds the max range size (512 MiB past default) for the table, the operation may fail, or cluster operation may suffer.

As a workaround, you can either manually separate a table's columns into multiple column families, or you can create a table-specific zone configuration with an increased max range size.

Simultaneous client connections and running queries on a single node

When a node has both a high number of customer connections and running queries, the node may crash due to memory burnout. This is due to CockroachDB not accurately limiting the number of clients and queries based on the amount of available RAM on the node.

To prevent retentiveness exhaustion, monitor each node'due south memory usage and ensure in that location is some margin between maximum CockroachDB retention usage and available system RAM. For more details virtually memory usage in CockroachDB, see this web log mail service.

Privileges for DELETE and UPDATE

Every DELETE or UPDATE statement constructs a SELECT statement, even when no WHERE clause is involved. Every bit a issue, the user executing DELETE or UPDATE requires both the DELETE and SELECT or UPDATE and SELECT privileges on the table.

ROLLBACK TO SAVEPOINT in high-priority transactions containing DDL

Transactions with priority HIGH that comprise DDL and ROLLBACK TO SAVEPOINT are non supported, as they could event in a deadlock. For case:

                          >              Begin              PRIORITY              Loftier              ;              SAVEPOINT              south              ;              CREATE              TABLE              t              (              10              INT              );              ROLLBACK              TO              SAVEPOINT              s              ;                      

            ERROR: unimplemented: cannot apply ROLLBACK TO SAVEPOINT in a HIGH PRIORITY transaction containing DDL SQLSTATE: 0A000 HINT: You lot take attempted to use a feature that is non yet implemented. Encounter: https://github.com/cockroachdb/cockroach/issues/46414                      

Tracking GitHub Issue

Concurrent SQL shells overwrite each other'due south history

The congenital-in SQL shell stores its command history in a unmarried file by default (.cockroachsql_history). When running multiple instances of the SQL crush on the same machine. Therefore, each shell's command history tin become overwritten in unexpected ways.

As a workaround, set the COCKROACH_SQL_CLI_HISTORY environment variable to unlike values for the 2 different shells, for example:

                          $                            consign                            COCKROACH_SQL_CLI_HISTORY              =.cockroachsql_history_shell_1                      

                          $                            export                            COCKROACH_SQL_CLI_HISTORY              =.cockroachsql_history_shell_2                      

Tracking GitHub Issue

Passwords with special characters must be passed as query parameters

When using cockroach commands, passwords with special characters must be passed equally query string parameters (east.g., postgres://maxroach@localhost:26257/movr?password=<password>) and not equally a component in the connectedness URL (eastward.chiliad., postgres://maxroach:<countersign>@localhost:26257/movr).

Tracking GitHub Result

CockroachDB does non examination for all connection failure scenarios

CockroachDB servers rely on the network to report when a TCP connection fails. In well-nigh scenarios when a connection fails, the network immediately reports a connection failure, resulting in a Connection refused mistake.

However, if there is no host at the target IP address, or if a firewall rule blocks traffic to the target address and port, a TCP handshake can linger while the client network stack waits for a TCP packet in response to network requests. To work effectually this kind of scenario, we recommend the following:

• When migrating a node to a new machine, keep the server listening at the previous IP address until the cluster has completed the migration.
• Configure any active network firewalls to let node-to-node traffic.
• Verify that orchestration tools (east.g., Kubernetes) are configured to use the correct network connection information.

Tracking GitHub Issue

Some column-dropping schema changes practice non roll back properly

Some schema changes that drib columns cannot be rolled back properly.

In some cases, the rollback will succeed, just the column data might be partially or totally missing, or stale due to the asynchronous nature of the schema modify.

Tracking GitHub Upshot

In other cases, the rollback will fail in such a way that will never exist cleaned upwards properly, leaving the table descriptor in a state where no other schema changes tin can exist run successfully.

Tracking GitHub Issue

To reduce the chance that a cavalcade drop will curlicue back incorrectly:

• Perform column drops in transactions separate from other schema changes. This ensures that other schema modify failures will not cause the column drop to be rolled back.

• Drop all constraints (including unique indexes) on the column in a separate transaction, earlier dropping the column.

• Drop any default values or computed expressions on a column before attempting to drop the column. This prevents conflicts between constraints and default/computed values during a column drop rollback.

If y'all think a rollback of a column-dropping schema modify has occurred, cheque the jobs tabular array. Schema changes with an error prefaced by cannot exist reverted, manual cleanup may be required might require transmission intervention.

Disk-spilling on joins with JSON columns

If the execution of a bring together query exceeds the limit set for retention-buffering operations (i.eastward., the value prepare for the sql.distsql.temp_storage.workmem cluster setting), CockroachDB will spill the intermediate results of computation to deejay. If the join operation spills to disk, and at least one of the equality columns is of type JSON, CockroachDB returns the error unable to encode table central: *tree.DJSON. If the memory limit is not reached, then the query volition be processed without error.

Tracking GitHub Effect

Disk-spilling not supported for some unordered singled-out operations

Deejay spilling isn't supported when running UPSERT statements that have nulls are singled-out and error on indistinguishable markers. You lot can cheque this by using Explicate and looking at the statement plan.

                          ├── distinct                     |                     |         │    │                           | distinct on         | ...         │    │                           | nulls are distinct  |         │    │                           | error on duplicate  |                      

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Source: https://www.cockroachlabs.com/docs/stable/known-limitations.html