From 312dedc0a3aea1833bb992f096121db4086fd075 Mon Sep 17 00:00:00 2001 From: jian he Date: Mon, 9 Feb 2026 11:14:15 +0800 Subject: [PATCH v25 3/4] Add option force_array for COPY JSON FORMAT --- doc/src/sgml/ref/copy.sgml | 30 +++++++++++++++++++++ src/backend/commands/copy.c | 13 +++++++++ src/backend/commands/copyto.c | 43 +++++++++++++++++++++++++++--- src/bin/psql/tab-complete.in.c | 2 +- src/include/commands/copy.h | 1 + src/test/regress/expected/copy.out | 23 ++++++++++++++++ src/test/regress/sql/copy.sql | 8 ++++++ 7 files changed, 115 insertions(+), 5 deletions(-) diff --git a/doc/src/sgml/ref/copy.sgml b/doc/src/sgml/ref/copy.sgml index 75f55bbf6f8..a79587f7613 100644 --- a/doc/src/sgml/ref/copy.sgml +++ b/doc/src/sgml/ref/copy.sgml @@ -40,6 +40,7 @@ COPY { table_name [ ( boolean | integer | MATCH ] QUOTE 'quote_character' ESCAPE 'escape_character' + FORCE_ARRAY [ boolean ] FORCE_QUOTE { ( column_name [, ...] ) | * } FORCE_NOT_NULL { ( column_name [, ...] ) | * } FORCE_NULL { ( column_name [, ...] ) | * } @@ -366,6 +367,19 @@ COPY { table_name [ ( + + FORCE_ARRAY + + + Force output of square brackets as array decorations at the beginning + and end of output, and commas between the rows. It is allowed only in + COPY TO, and only when using + json format. The default is + false. + + + + FORCE_QUOTE @@ -1103,6 +1117,22 @@ COPY country TO STDOUT (DELIMITER '|'); + + When the FORCE_ARRAY option is enabled, + the entire output is wrapped in a single JSON array with rows separated by commas: + +COPY (SELECT * FROM (VALUES(1),(2)) val(id)) TO STDOUT (FORMAT JSON, FORCE_ARRAY); + +The output is as follows: + +[ + {"id":1} +,{"id":2} +] + + + + To copy data from a file into the country table: diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c index 29c121c7f08..84254d46a67 100644 --- a/src/backend/commands/copy.c +++ b/src/backend/commands/copy.c @@ -569,6 +569,7 @@ ProcessCopyOptions(ParseState *pstate, bool on_error_specified = false; bool log_verbosity_specified = false; bool reject_limit_specified = false; + bool force_array_specified = false; ListCell *option; /* Support external use for option sanity checking */ @@ -725,6 +726,13 @@ ProcessCopyOptions(ParseState *pstate, defel->defname), parser_errposition(pstate, defel->location))); } + else if (strcmp(defel->defname, "force_array") == 0) + { + if (force_array_specified) + errorConflictingDefElem(defel, pstate); + force_array_specified = true; + opts_out->force_array = defGetBoolean(defel); + } else if (strcmp(defel->defname, "on_error") == 0) { if (on_error_specified) @@ -967,6 +975,11 @@ ProcessCopyOptions(ParseState *pstate, errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("COPY %s mode cannot be used with %s", "JSON", "COPY FROM")); + if (opts_out->format != COPY_FORMAT_JSON && opts_out->force_array) + ereport(ERROR, + errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("COPY %s can only be used with JSON mode", "FORCE_ARRAY")); + if (opts_out->default_print) { if (!is_from) diff --git a/src/backend/commands/copyto.c b/src/backend/commands/copyto.c index 96605079eeb..a7615cc34ec 100644 --- a/src/backend/commands/copyto.c +++ b/src/backend/commands/copyto.c @@ -88,6 +88,7 @@ typedef struct CopyToStateData bool is_program; /* is 'filename' a program to popen? */ /* JSON format state */ + bool json_row_delim_needed; /* need delimiter before next row */ bool json_tupledesc_ready; /* TupleDesc setup done for JSON */ StringInfoData json_buf; /* reusable buffer for JSON output */ @@ -138,6 +139,7 @@ static void CopyToTextLikeOneRow(CopyToState cstate, TupleTableSlot *slot, bool is_csv); static void CopyToTextLikeEnd(CopyToState cstate); static void CopyToJsonOneRow(CopyToState cstate, TupleTableSlot *slot); +static void CopyToJsonEnd(CopyToState cstate); static void CopyToBinaryStart(CopyToState cstate, TupleDesc tupDesc); static void CopyToBinaryOutFunc(CopyToState cstate, Oid atttypid, FmgrInfo *finfo); static void CopyToBinaryOneRow(CopyToState cstate, TupleTableSlot *slot); @@ -157,8 +159,9 @@ static void CopySendInt16(CopyToState cstate, int16 val); /* * COPY TO routines for built-in formats. * - * CSV, text and json formats share the same TextLike routines except for the - * one-row callback. + * Text and CSV formats share the same TextLike routines except for the + * one-row callback. JSON shares the start and outfunc callbacks with + * text/CSV, but has its own one-row and end callbacks. */ /* text format */ @@ -182,7 +185,7 @@ static const CopyToRoutine CopyToRoutineJson = { .CopyToStart = CopyToTextLikeStart, .CopyToOutFunc = CopyToTextLikeOutFunc, .CopyToOneRow = CopyToJsonOneRow, - .CopyToEnd = CopyToTextLikeEnd, + .CopyToEnd = CopyToJsonEnd, }; /* binary format */ @@ -258,6 +261,15 @@ CopyToTextLikeStart(CopyToState cstate, TupleDesc tupDesc) oldcxt = MemoryContextSwitchTo(cstate->copycontext); initStringInfo(&cstate->json_buf); MemoryContextSwitchTo(oldcxt); + + /* + * If FORCE_ARRAY has been specified, send the opening bracket. + */ + if (cstate->opts.force_array) + { + CopySendChar(cstate, '['); + CopySendTextLikeEndOfRow(cstate); + } } } @@ -335,7 +347,7 @@ CopyToTextLikeOneRow(CopyToState cstate, CopySendTextLikeEndOfRow(cstate); } -/* Implementation of the end callback for text, CSV, and json formats */ +/* Implementation of the end callback for text and CSV formats */ static void CopyToTextLikeEnd(CopyToState cstate) { @@ -371,11 +383,34 @@ CopyToJsonOneRow(CopyToState cstate, TupleTableSlot *slot) resetStringInfo(&cstate->json_buf); composite_to_json(rowdata, &cstate->json_buf, false); + if (cstate->opts.force_array) + { + if (cstate->json_row_delim_needed) + CopySendChar(cstate, ','); + else + { + /* first row needs no delimiter */ + CopySendChar(cstate, ' '); + cstate->json_row_delim_needed = true; + } + } + CopySendData(cstate, cstate->json_buf.data, cstate->json_buf.len); CopySendTextLikeEndOfRow(cstate); } +/* Implementation of the end callback for json format */ +static void +CopyToJsonEnd(CopyToState cstate) +{ + if (cstate->opts.force_array) + { + CopySendChar(cstate, ']'); + CopySendTextLikeEndOfRow(cstate); + } +} + /* * Implementation of the start callback for binary format. Send a header * for a binary copy. diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c index d257837b0c5..76d3258e92b 100644 --- a/src/bin/psql/tab-complete.in.c +++ b/src/bin/psql/tab-complete.in.c @@ -1232,7 +1232,7 @@ Copy_common_options, "DEFAULT", "FORCE_NOT_NULL", "FORCE_NULL", "FREEZE", \ /* COPY TO options */ #define Copy_to_options \ -Copy_common_options, "FORCE_QUOTE" +Copy_common_options, "FORCE_QUOTE", "FORCE_ARRAY" /* * These object types were introduced later than our support cutoff of diff --git a/src/include/commands/copy.h b/src/include/commands/copy.h index 2b5bef6738e..abecfe51098 100644 --- a/src/include/commands/copy.h +++ b/src/include/commands/copy.h @@ -88,6 +88,7 @@ typedef struct CopyFormatOptions List *force_notnull; /* list of column names */ bool force_notnull_all; /* FORCE_NOT_NULL *? */ bool *force_notnull_flags; /* per-column CSV FNN flags */ + bool force_array; /* add JSON array decorations */ List *force_null; /* list of column names */ bool force_null_all; /* FORCE_NULL *? */ bool *force_null_flags; /* per-column CSV FN flags */ diff --git a/src/test/regress/expected/copy.out b/src/test/regress/expected/copy.out index 4ea658a45de..a7e88b711d7 100644 --- a/src/test/regress/expected/copy.out +++ b/src/test/regress/expected/copy.out @@ -114,6 +114,29 @@ ERROR: COPY JSON mode cannot be used with COPY FROM copy copytest (style) to stdout (format json); ERROR: column selection is not supported in JSON mode -- all of the above should yield error +-- should fail: force_array requires json format +copy copytest to stdout (format csv, force_array true); +ERROR: COPY FORCE_ARRAY can only be used with JSON mode +-- force_array variants +copy copytest to stdout (format json, force_array); +[ + {"style":"DOS","test":"abc\r\ndef","filler":1} +,{"style":"Unix","test":"abc\ndef","filler":2} +,{"style":"Mac","test":"abc\rdef","filler":3} +,{"style":"esc\\ape","test":"a\\r\\\r\\\n\\nb","filler":4} +] +copy copytest to stdout (format json, force_array true); +[ + {"style":"DOS","test":"abc\r\ndef","filler":1} +,{"style":"Unix","test":"abc\ndef","filler":2} +,{"style":"Mac","test":"abc\rdef","filler":3} +,{"style":"esc\\ape","test":"a\\r\\\r\\\n\\nb","filler":4} +] +copy copytest to stdout (format json, force_array false); +{"style":"DOS","test":"abc\r\ndef","filler":1} +{"style":"Unix","test":"abc\ndef","filler":2} +{"style":"Mac","test":"abc\rdef","filler":3} +{"style":"esc\\ape","test":"a\\r\\\r\\\n\\nb","filler":4} -- embedded escaped characters create temp table copyjsontest ( id bigserial, diff --git a/src/test/regress/sql/copy.sql b/src/test/regress/sql/copy.sql index c558eba202a..ae202fc5e8d 100644 --- a/src/test/regress/sql/copy.sql +++ b/src/test/regress/sql/copy.sql @@ -102,6 +102,14 @@ copy copytest from stdin(format json); copy copytest (style) to stdout (format json); -- all of the above should yield error +-- should fail: force_array requires json format +copy copytest to stdout (format csv, force_array true); + +-- force_array variants +copy copytest to stdout (format json, force_array); +copy copytest to stdout (format json, force_array true); +copy copytest to stdout (format json, force_array false); + -- embedded escaped characters create temp table copyjsontest ( id bigserial, -- 2.43.0