Version 2.3.0, released 2020-09-24
  Note: When upgrading from an older version of oracle_fdw, make sure to run
        ALTER EXTENSION oracle_fdw UPDATE;
        after installing the extension.

  Enhancements:
  - Support PostgreSQL v13.  Support for 9.2 and 9.1 is dropped.
  - Add a function "oracle_execute" to execute arbitrary SQL statements on
    Oracle.  The statements must not return a result (e.g. DDL statements).
  - Add an option "dblink" for Oracle database links.
    The option can be used on foreign tables or with IMPORT FOREIGN SCHEMA.
    Patch by Nicolas Boullis.
  - Add a column option "strip_zeros" that automatically strips ASCII 0
    characters from strings.
    Per request from Alexander Lampalzer.
  - New IMPORT FOREIGN SCHEMA options "max_long", "sample_percent" and
    "prefetch".  These set the corresponding options on imported tables.
    Suggested by "ferfebles".
  - Add support for isolation levels other than SERIALIZABLE.
    This is mostly because Oracle's implementation of SERIALIZABLE is so buggy.
    Patch by Jet C.X. Zhang.

  Bugfixes:
  - Fix bad results with uncorrelated subqueries.
    This affects queries have a foreign scan with a filter based on a subplan.
    Reported by "srakazmus".
  - Fix "Internal oracle_fdw error: encountered unknown node type 144"
    This can happen in plans involving tables with identity columns.
    Reported by Yang Lin.
  - Don't throw an error if DML statements modify no rows.
    This might be caused by a trigger on the Oracle side.
    Reported by Andrey Marinchuk.
  - Fix NCHAR and NVARCHAR2 handling.
    With single-byte Oracle character sets, this bug led to replacement
    characters being used for characters not in the database character set.
    Reported by "srakazmus", and Christian Ullrich helped with the fix.
  - Report a proper error for INSERT ... ON CONFLICT on partitioned tables.
    Report and fix by Ian Barwick.
  - Fix INSERT ... RETURNING if a table partition is a foreign table.
    It used to return NULL values by mistake.
    Report and analysis by Ian Barwick.

Version 2.2.0, released 2019-10-10
  Enhancements:
  - Add support for COPY to foreign tables (from PostgreSQL v11 on).
    This caused a crash before, as reported by "jkldv".
  - Add a new "collation" option for IMPORT FOREIGN SCHEMA that controls
    case folding.
    Patch by Sahap Asci.
  - Add support for Oracle XMLTYPE.
  - Set V$SESSION_CONNECT_INFO.CLIENT_DRIVER to "oracle_fdw".
    This makes it easier to identify the session on the Oracle side.

  Bugfixes:
  - Fix crash or bad results with pushed down join queries.
    The query target list can change during query planning, but oracle_fdw
    relied on the one from before.
    This bug only manifests in PostgreSQL v11.
    Bug found by Jaime Casanova and fixed by Tatsuro Yamada.
  - Fix push-down of foreign scan conditions with variables belonging
    to other tables.
    This can lead to wrong results and warnings like:
    WARNING:  column number x of foreign table "y" does not exist in
              foreign Oracle table, will be replaced by NULL
  - Fix crash in UPDATE or DELETE where the optimizer can deduce that no
    scan is required, for example with "WHERE 1 = 0".
    Reported by Andy Shipman.
  - Fix crash or bad results in queries with IN or "= ANY" where the element
    type on the right-hand side is different from the left-hand side type.
  - Add support for reading infinite NUMBERs.
    Oracle NUMBER has infinite values, which are represented as "~" and "-~".
    Since PostgreSQL's "numeric" does not know infinity, map these values
    to NaN in this case.  For "real" and "double precision" we can use the
    normal infinity values.
  - The "readonly" option of IMPORT FOREIGN SCHEMA didn't work properly:
    When set to "false", it would still create read-only foreign tables.
    Reported by Jacob Roberts.

Version 2.1.0, released 2018-10-01
  Enhancements:
  - Add support for the "json" PostgreSQL data type.
    On the Oracle side, CLOB or VARCHAR2 can be used.
    Suggested by "bsislow".
  - Add support and documentation for building with Microsoft Visual Studio.
    Patch by Christian Ullrich.
  - Enable delayed loading of the Oracle DLL on Windows.
    This allows better diagnostic messages if the library cannot be loaded.
    Patch by Christian Ullrich.
  - Report the correct SQLSTATE for constraint violation and deadlock errors.
    Idea by "omistler".
  - Push down outer joins to Oracle.
    Patch by Tatsuro Yamada, courtesy of NTT OSS Center.

  Bugfixes:
  - Missing check if Oracle data types can be converted to PostgreSQL types.
    This bug was introduced in 2.0.0.
  - When oracle_fdw is loaded, initializing background workers
    (e.g. for parallel query) failed with:
       ERROR:  invalid cache ID: 41
  - Don't try to push down IS [NOT] DISTINCT FROM expressions.
    Oracle does not support this standard SQL syntax.
  - Don't push down IS [NOT] NULL tests on boolean expressions.
    This caused "ORA-00907: missing right parenthesis".
    Noticed by Tatsuro Yamada during testing with "sqlsmith".
  - Allow foreign tables to be defined on Oracle queries that contain double
    quotes.  This caused an error message due to a sanity check that has become
    obsolete when this feature was introduced.
    Noted by "Bpapman".
  - Disable push-down of foreign joins in queries with FOR UPDATE.
    These used to be pushed down before, but without the FOR UPDATE clause,
    leading to incorrect behavior in the face of concurrency.
    Noted and fixed by Tatsuro Yamada.

Version 2.0.0, released 2017-09-15
  Incompatible changes:
  - Remove the deprecated option "plan_costs", since it is not very useful and
    is a maintenance burden.  After an upgrade, tables with this option set
    should be updated with:
    ALTER FOREIGN TABLE ... OPTIONS (DROP plan_costs);

  Enhancements:
  - Push down 2-way inner joins in SELECT statements if all conditions
    can be pushed down.
    Patch by Tatsuro Yamada, courtesy of NTT OSS Center.

  Bugfixes:
  - oracle_fdw crashed on Windows if queries use a NULL parameter or
    an empty subselect.
    Report by PAscal Lemoy.
  - Reading "srid.map" sometimes caused errors even if everything was alright.
    Report by Paul Dziemiela, analysis by Christian Ullrich.
  - Don't push down expressions with CLOB column references.
    Because of Oracle's inability to use CLOB in SQL expressions,
    this could lead to errors like
       ORA-00932: inconsistent datatypes: expected - got CLOB
  - Fix bug in "pg_terminate_backend" handling.
    "pg_terminate_backend" (or SIGTERM) was not handled
    correctly, since neither the Oracle query was canceled nor did
    the backend terminate.
    Reported by Dmitry Chirkin.

Version 1.5.0, released 2016-08-05
  Enhancements:
  - Add table option "sample_percent" to ANALYZE very large tables
    This can speed up ANALYZE significantly.
    Idea by PAscal Lemoy.
  - Introduce a table option "prefetch" for the Oracle row prefetch count
    This can speed up foreign table scans.
    Per discussion with by PAscal Lemoy and Maurizio De Giorgi.
  - Push down arbitrary IN and NOT IN expressions
    Up to now, only lists with constants were considered.
    Per request from Volkmar Bühringer.
  - Push down ORDER BY expressions to Oracle from PostgreSQL 9.2 on
    Only expressions of numeric, date and timestamp datatypes are pushed
    down, since the string collations in PostgreSQL and Oracle cannot be
    guaranteed to be the same.
    Courtesy of NTT OSS Center, patch by Tatsuro Yamada.

  Bugfixes:
  - Fix errors with now() and date/timestamp parameters in queries
    This bug was introduced in 1.3.0 and caused errors like
    ERROR:  error executing query: OCIDateTimeFromText failed to convert parameter
    DETAIL:  ORA-01843: not a valid month
    when now() or "current_timestamp" and friends or date/timestamp
    parameters were used.
    Report by Li Hailong.
  - Fix errors when updating date/timestamp columns
    This bug was also introduced in 1.3.0 and caused errors like
    ORA-01856: BC/B.C. or AD/A.D. required
    if the Oracle and PostgreSQL types were different.
    Report by Stephane Tachoires.
  - IMPORT FOREIGN SCHEMA sometimes didn't import primary keys
    Report by Jean-Marc Lessard, fix by PAscal Lemoy.
  - Fix memory leaks during ANALYZE
    This caused out of memory errors when large tables were analyzed.
    Report by Alessio Checcucci.
  - IMPORT FOREIGN SCHEMA should not tolerate missing remote schema
    It used to cause a warning, but the SQL standard requires an error.
    Report by Jean-Marc Lessard.
  - Fix crash when UPDATEing non-existent columns
    If a foreign table has more columns than the underlying Oracle table,
    these additional columns are treated as containing NULLs.
    However, oracle_fdw crashed on an attempt to change such a column with
    an UPDATE statement, which should not happen.
    Reported by Fabien Nicollet.
  - Fetch all columns from Oracle when the whole row is referenced
    This problem could lead to wrong NULL values in trigger functions or when
    the whole column is used in an expression.
    Reported by Fabien Nicollet.

Version 1.4.0, released 2016-04-08
  Enhancements:
  - Add option "readonly" for IMPORT FOREIGN TABLE that sets the foreign table
    option "readonly" to "true" on all imported foreign tables.
    Idea by Julien Goux.
  - Allow foreign tables based on arbitrary Oracle queries.
    The query, enclosed in parentheses, can be supplied as option "table".
    Requested by "tsykes", "cirix81" and Julien Goux.

  Bugfixes:
  - Selecting timestamps with lc_messages other than English caused errors like
    "ORA-01406: la valeur de la colonne extraite a été tronquée"
    Report by Damien Szczyt.
  - Complicated queries could lead to an error like
    "Internal oracle_fdw error: encountered unknown node type 524."
    Report by "bartonjd".
  - PostGIS type "geometry" cannot be found if ArcGIS is installed.
    Report by "dtoller".

Version 1.3.0, released 2015-12-21
  Enhancements:
  - Add support for IMPORT FOREIGN SCHEMA for PostgreSQL 9.5 and higher.
  - Improve cost estimates by using the row count estimate.
    Inspiration by Daniele Sevegnani.
  - Support two-dimensional geometries with an additional measure dimension.
    Idea by Paul Dziemiela.
  - Throw an error if oracle_close_connections() is called inside a
    transaction that modified Oracle data.

  Bugfixes:
  - The server crashed for the constructs like "<column> = ANY (NULL)".
    Report and patch by dreckard.
  - oracle_fdw sometimes failed to recognize the SDO_GEOMETRY data type.
    Per report from Bevan Jenkins.
  - Some point geometries were not translated properly.
    Per report from Bevan Jenkins.
  - Ignore SDO_GEOMETRY elements with zero SDO_ETYPE.
    According to Oracle, that is the correct behaviour.
    Per report from Bevan Jenkins.
  - Fix EXPLAIN (VERBOSE) for queries containing current_timestamp.
    This caused "ORA-30081: invalid data type for datetime/interval arithmetic".
    Noticed by "kkwhite".
  - Oracle TIMESTAMP(0) fields caused errors like:
    ERROR: invalid input syntax for type timestamp: "1977-06-09 18:00:00."
    Also, handling of dates and timestamps before Christ was broken.
    Report by "abiuan".

Version 1.2.0, released 2015-01-03
  Enhancements:
  - Add support for a file "srid.map" to translate SRIDs between Oracle
    and PostGIS.
  - If the Oracle session has been terminated outside of a transaction,
    try to reconnect once.
    Idea by AVEN.

  Bugfixes:
  - Prepared statements with parameters can crash.
    Because of custom plans, this does not manifest until the query has been
    executed several times in PostgreSQL 9.2 and higher.
    Per report from Krzysztof Gorczyński and others.
    This bug was introduced in 1.1.0.

Version 1.1.0, released 2014-12-03
  Enhancements:
  - Add efficient support for translating between Oracle SDO_GEOMETRY and
    PostGIS geometry.  Supported geometry types are POINT, LINE, POLYGON,
    MULTIPOINT, MULTILINE and MULTIPOLYGON.
    Courtesy of Oslandia, implemented by Vincent Mora.
  - Add regression tests for improved quality.
  - Bind LOB data instead of LOB locators for INSERT and UPDATE.
    This simplifies the code and makes Oracle triggers on LOB columns
    behave as expected.

  Bugfixes:
  - Fix a bug introduced in 1.0.0 that leads to crashes when LOB columns
    are modified.
  - Fix several crashes when the foreign table has fewer or more columns
    than the Oracle table.
  - Fix a bug that caused "RETURNING <expression>" to return NULL for
    complex expressions.
  - Writing date or timestamp columns failed when DateStyle was not ISO.
  - Reading or writing negative INTERVAL DAY TO SECOND resulted in bad
    values because the string formats in PostgreSQL and Oracle differ.

Version 1.0.0, released 2014-04-08
  Enhancements:
  - Add function oracle_diag(name) for diagnostic purposes.
    ATTENTION: Use "ALTER EXTENSION oracle_fdw UPDATE" when upgrading
    from a previous version of oracle_fdw.
  - Avoid unnecessary local filtering for pushed down WHERE clauses with
    internal parameters.
  - Add support for triggers on foreign tables for PostgreSQL 9.4.

  Bugfixes:
  - Fix logic error that keeps Oracle connections from closing.
  - Fix "cache lookup failed for type 0" in queries with string parameters.
    Per report from Adolfho Lopes.

Version 0.9.10 (beta), released 2013-12-24
  Enhancements:
  - Add support for INSERT, DELETE and UPDATE.
    This is a major rewrite that might cause some destabilization in
    existing functionality.
  - Add new column option "key" to indicate primary key columns.
    This is needed for UPDATE and DELETE.
  - Add new table option "readonly" to forbid data modifying statements.
  - Improved transaction handling for data modifying statements.
    COMMIT, ROLLBACK and SAVEPOINT will work as expected.
  - Add paths for Oracle 12.1 to the Makefile.
    Patch by Guillaume Lelarge.

  Bugfixes:
  - Don't try to push down the division operator.
    That would produce incorrect results for numeric data types.

Version 0.9.9 (beta), released 2013-08-07
  Enhancements:
  - Enable build with PostgreSQL 9.3.

  Bugfixes:
  - Fix error "ORA-01406: fetched column value was truncated"
    caused by timestamps with precision greater than 6.
    Per report from David E. Wheeler.
  - Fix crash with IN lists that do not entirely consist of constants.
    Per report from Wang Dong.
  - Fix handling of parameters during pushdown of WHERE conditions.
    The previous implementation returned incorrect results for certain
    queries like SELECT ... WHERE colname = (SELECT ...)
    ATTENTION: Since correct handling of parameters is not possible before
    PostgreSQL 9.2, query parameters will not be pushed down in PostgreSQL 9.1.
    This is a regression for cases where this happened to work.
  - Fix a logical error that can lead to incorrect Oracle WHERE clauses.
  - Fix a bug that can lead to the incorrect omission of a scan clause,
    leading to wrong results.

Version 0.9.8 (beta), released 2012-10-16
  Enhancements:
  - Add support for pushdown of IN and NOT IN clauses in WHERE conditions.
    As suggested by Wang Dong.

  Bugfixes:
  - Add check to make sure that character string data are properly encoded.
    This is necessary because Oracle does not check this properly.
    Per report from David E. Wheeler.

Version 0.9.7 (beta), released 2012-09-07
  Bugfixes:
  - Avoid failure to describe synonyms under certain conditions.
    ATTENTION: This constitutes a compatibility break: table and schema names
    now have to be exactly as they are in Oracle's catalogs, i.e. without
    double quotes and normally in uppercase.
    Per report from Bry Lo.
  - Add paths to Makefile so that we can build with Instant Client RPMs.
    Noticed by Andrew Theaker.
  - Fix a memory corruption bug that can lead to crashes, errors and
    wrong results.
  - Improve bad performance of "SELECT count(*)" on foreign tables.
    This is a simple workaround for the (not yet confirmed)
    Oracle bug 14562530.

Version 0.9.6 (beta), released 2012-06-25
  Enhancements:
  - Support Oracle types LONG and LONG RAW.
    Introduce table option "max_long" (default 32767) to set the maximal
    length of such columns.

  Bugfixes:
  - Fix a bug that causes a server crash when the PostgreSQL session is
    terminated if the only statements involving oracle_fdw during that
    session were CREATE statements.
    Per report from Bry Lo.

Version 0.9.5 (beta), released 2012-05-11
  Enhancements:
  - Support ANALYZE on foreign tables (from PostgreSQL 9.2 on).

  Bugfixes:
  - Fix a bug that leads to warnings and sometimes bad results if system
    columns of the foreign table are referenced.
  - Fix wrong column width estimates of plan_costs=on.

Version 0.9.4 (beta), released 2012-03-19
  Enhancements:
  - Support the new foreign data wrapper API introduced in 9.2.
    In PostgreSQL 9.2 and above, WHERE conditions that get pushed down to
    Oracle will not be checked a second time.
  - Improve error messages for errors during conversion of Oracle data
    so that the problem can be diagnosed.

  Bugfixes:
  - Fix uninitialized value that caused intermittent server crashes.
    Per report from Bruno Voigt.
  - Rework the handling of errors and transactions.  Now an error should not
    be able to cause an Oracle transaction to be left open.  This also fixes
    a bug introduced in 0.9.3 that prevented Oracle errors from being
    reported as DETAIL message.  Also, all foreign scans in one local query
    will now be executed within one Oracle transaction if they belong to
    the same Oracle session.
  - Rework memory management to exclude memory leaks under all circumstances.

Version 0.9.3 (beta), released 2012-02-07
  Enhancements:
  - Add support for PostgreSQL data type "uuid".

  Bugfixes:
  - After an error message, calls to the foreign server result in this error:
      error connecting to Oracle: OCITransStart failed to start a transaction
      ORA-01453: SET TRANSACTION must be first statement of transaction
    The problem is that the previous transaction was not closed.
    This used to go unnoticed, the problem now becomes manifest because we
    explicitly start a serializable transaction.
    Per reports from Keith Fiske and Bruno Voigt.

Version 0.9.2 (beta), released 2011-12-30
  Bugfixes:
  - Fix handling of Oracle BFILE columns.  This was totally broken; attempts
    to select such columns resulted in the error message
    'ORA-00932: inconsistent datatypes: expected %s got %s'.
    Bug report and patch by Dominique Legendre.
  - Use a serializable transaction in Oracle to make sure that consistent
    data are retrieved during a rescan.

Version 0.9.1 (beta), released 2011-09-14
  Bugfixes:
  - Fix incorrect use of an automatic variable for binding timestamp parameters
    in Oracle.
  - Remove unnecessary lvalue casts.
    These violate the C standard and cause errors on gcc 4.
    Per report from Dominique Legendre.
  - Fix lack of support for dropped columns in foreign table.
    oracle_fdw incorrectly assumed that the n-th PostgreSQL column corresponds
    to the n-th Oracle column.  This leads to confusion in the presence of
    dropped columns, which retain an entry in pg_attribute.
    Per report from Dominique Legendre.
  - Fix typo that caused wrong and negative sizes being assumed for longer
    Oracle columns.  This led to palloc() errors and Oracle fetch errors.
    Per report from Dominique Legendre.

Version 0.9 (beta), released 2011-08-25
  - initial release
