allow psql to watch \dt

Started by Justin Pryzbyalmost 8 years ago2 messageshackers
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#1Justin Pryzby
pryzby@telsasoft.com

I thought that would be desirable, although I don't see any better way of
getting there than this.

I don't see other commands for which which watch is wanted...but who am I to
say that watching creation extention isn't useful? So I imagine this should be
generalized to save query buffer for all \d commands.

BTW, for amusement value, I briefly looked at implementing it for \!

diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 4c85f43..580d708 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -68,7 +68,7 @@ static backslashResult exec_command_copy(PsqlScanState scan_state, bool active_b
 static backslashResult exec_command_copyright(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_crosstabview(PsqlScanState scan_state, bool active_branch);
 static backslashResult exec_command_d(PsqlScanState scan_state, bool active_branch,
-			   const char *cmd);
+			   const char *cmd, PQExpBuffer query_buf);
 static backslashResult exec_command_edit(PsqlScanState scan_state, bool active_branch,
 				  PQExpBuffer query_buf, PQExpBuffer previous_buf);
 static backslashResult exec_command_ef_ev(PsqlScanState scan_state, bool active_branch,
@@ -310,7 +310,7 @@ exec_command(const char *cmd,
 	else if (strcmp(cmd, "crosstabview") == 0)
 		status = exec_command_crosstabview(scan_state, active_branch);
 	else if (cmd[0] == 'd')
-		status = exec_command_d(scan_state, active_branch, cmd);
+		status = exec_command_d(scan_state, active_branch, cmd, query_buf);
 	else if (strcmp(cmd, "e") == 0 || strcmp(cmd, "edit") == 0)
 		status = exec_command_edit(scan_state, active_branch,
 								   query_buf, previous_buf);
@@ -693,7 +693,7 @@ exec_command_crosstabview(PsqlScanState scan_state, bool active_branch)
  * \d* commands
  */
 static backslashResult
-exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
+exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd, PQExpBuffer query_buf)
 {
 	backslashResult status = PSQL_CMD_SKIP_LINE;
 	bool		success = true;
@@ -720,7 +720,7 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 					success = describeTableDetails(pattern, show_verbose, show_system);
 				else
 					/* standard listing of interesting things */
-					success = listTables("tvmsE", NULL, show_verbose, show_system);
+					success = listTables("tvmsE", NULL, show_verbose, show_system, query_buf);
 				break;
 			case 'A':
 				success = describeAccessMethods(pattern, show_verbose);
@@ -794,7 +794,7 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 			case 'i':
 			case 's':
 			case 'E':
-				success = listTables(&cmd[1], pattern, show_verbose, show_system);
+				success = listTables(&cmd[1], pattern, show_verbose, show_system, query_buf);
 				break;
 			case 'r':
 				if (cmd[2] == 'd' && cmd[3] == 's')
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 410131e..b637e1b 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3404,7 +3404,7 @@ listDbRoleSettings(const char *pattern, const char *pattern2)
  * (any order of the above is fine)
  */
 bool
-listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSystem)
+listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSystem, PQExpBuffer buf)
 {
 	bool		showTables = strchr(tabtypes, 't') != NULL;
 	bool		showIndexes = strchr(tabtypes, 'i') != NULL;
@@ -3413,7 +3413,6 @@ listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSys
 	bool		showSeq = strchr(tabtypes, 's') != NULL;
 	bool		showForeign = strchr(tabtypes, 'E') != NULL;

- PQExpBufferData buf;
PGresult *res;
printQueryOpt myopt = pset.popt;
static const bool translate_columns[] = {false, false, true, false, false, false, false};
@@ -3422,13 +3421,13 @@ listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSys
if (!(showTables || showIndexes || showViews || showMatViews || showSeq || showForeign))
showTables = showViews = showMatViews = showSeq = showForeign = true;

-	initPQExpBuffer(&buf);
+	initPQExpBuffer(buf);

/*
* Note: as of Pg 8.2, we no longer use relkind 's' (special), but we keep
* it here for backwards compatibility.
*/
- printfPQExpBuffer(&buf,
+ printfPQExpBuffer(buf,
"SELECT n.nspname as \"%s\",\n"
" c.relname as \"%s\",\n"
" CASE c.relkind"
@@ -3458,7 +3457,7 @@ listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSys
gettext_noop("Owner"));

if (showIndexes)
- appendPQExpBuffer(&buf,
+ appendPQExpBuffer(buf,
",\n c2.relname as \"%s\"",
gettext_noop("Table"));

@@ -3469,50 +3468,50 @@ listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSys
* size of a table, including FSM, VM and TOAST tables.
*/
if (pset.sversion >= 90000)
- appendPQExpBuffer(&buf,
+ appendPQExpBuffer(buf,
",\n pg_catalog.pg_size_pretty(pg_catalog.pg_table_size(c.oid)) as \"%s\"",
gettext_noop("Size"));
else if (pset.sversion >= 80100)
- appendPQExpBuffer(&buf,
+ appendPQExpBuffer(buf,
",\n pg_catalog.pg_size_pretty(pg_catalog.pg_relation_size(c.oid)) as \"%s\"",
gettext_noop("Size"));

- appendPQExpBuffer(&buf,
+ appendPQExpBuffer(buf,
",\n pg_catalog.obj_description(c.oid, 'pg_class') as \"%s\"",
gettext_noop("Description"));
}

- appendPQExpBufferStr(&buf,
+ appendPQExpBufferStr(buf,
"\nFROM pg_catalog.pg_class c"
"\n LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace");
if (showIndexes)
- appendPQExpBufferStr(&buf,
+ appendPQExpBufferStr(buf,
"\n LEFT JOIN pg_catalog.pg_index i ON i.indexrelid = c.oid"
"\n LEFT JOIN pg_catalog.pg_class c2 ON i.indrelid = c2.oid");

-	appendPQExpBufferStr(&buf, "\nWHERE c.relkind IN (");
+	appendPQExpBufferStr(buf, "\nWHERE c.relkind IN (");
 	if (showTables)
-		appendPQExpBufferStr(&buf, CppAsString2(RELKIND_RELATION) ","
+		appendPQExpBufferStr(buf, CppAsString2(RELKIND_RELATION) ","
 							 CppAsString2(RELKIND_PARTITIONED_TABLE) ",");
 	if (showViews)
-		appendPQExpBufferStr(&buf, CppAsString2(RELKIND_VIEW) ",");
+		appendPQExpBufferStr(buf, CppAsString2(RELKIND_VIEW) ",");
 	if (showMatViews)
-		appendPQExpBufferStr(&buf, CppAsString2(RELKIND_MATVIEW) ",");
+		appendPQExpBufferStr(buf, CppAsString2(RELKIND_MATVIEW) ",");
 	if (showIndexes)
-		appendPQExpBufferStr(&buf, CppAsString2(RELKIND_INDEX) ","
+		appendPQExpBufferStr(buf, CppAsString2(RELKIND_INDEX) ","
 							 CppAsString2(RELKIND_PARTITIONED_INDEX) ",");
 	if (showSeq)
-		appendPQExpBufferStr(&buf, CppAsString2(RELKIND_SEQUENCE) ",");
+		appendPQExpBufferStr(buf, CppAsString2(RELKIND_SEQUENCE) ",");
 	if (showSystem || pattern)
-		appendPQExpBufferStr(&buf, "'s',"); /* was RELKIND_SPECIAL */
+		appendPQExpBufferStr(buf, "'s',"); /* was RELKIND_SPECIAL */
 	if (showForeign)
-		appendPQExpBufferStr(&buf, CppAsString2(RELKIND_FOREIGN_TABLE) ",");
+		appendPQExpBufferStr(buf, CppAsString2(RELKIND_FOREIGN_TABLE) ",");
-	appendPQExpBufferStr(&buf, "''");	/* dummy */
-	appendPQExpBufferStr(&buf, ")\n");
+	appendPQExpBufferStr(buf, "''");	/* dummy */
+	appendPQExpBufferStr(buf, ")\n");
 	if (!showSystem && !pattern)
-		appendPQExpBufferStr(&buf, "      AND n.nspname <> 'pg_catalog'\n"
+		appendPQExpBufferStr(buf, "      AND n.nspname <> 'pg_catalog'\n"
 							 "      AND n.nspname <> 'information_schema'\n");
 	/*
@@ -3522,16 +3521,15 @@ listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSys
 	 * be shown.  Use plain \d if you really need to look at a TOAST
 	 * table/index.
 	 */
-	appendPQExpBufferStr(&buf, "      AND n.nspname !~ '^pg_toast'\n");
+	appendPQExpBufferStr(buf, "      AND n.nspname !~ '^pg_toast'\n");
-	processSQLNamePattern(pset.db, &buf, pattern, true, false,
+	processSQLNamePattern(pset.db, buf, pattern, true, false,
 						  "n.nspname", "c.relname", NULL,
 						  "pg_catalog.pg_table_is_visible(c.oid)");
-	appendPQExpBufferStr(&buf, "ORDER BY 1,2;");
+	appendPQExpBufferStr(buf, "ORDER BY 1,2;");
-	res = PSQLexec(buf.data);
-	termPQExpBuffer(&buf);
+	res = PSQLexec(buf->data);
 	if (!res)
 		return false;
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index a4cc5ef..57f2964 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -61,7 +61,7 @@ extern bool listTSTemplates(const char *pattern, bool verbose);
 extern bool listAllDbs(const char *pattern, bool verbose);
 /* \dt, \di, \ds, \dS, etc. */
-extern bool listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSystem);
+extern bool listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSystem, PQExpBuffer buf);

/* \dD */
extern bool listDomains(const char *pattern, bool verbose, bool showSystem);

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Justin Pryzby (#1)
Re: allow psql to watch \dt

Justin Pryzby <pryzby@telsasoft.com> writes:

I thought that would be desirable, although I don't see any better way of
getting there than this.

Hm, but a lot of the \d commands involve more than one underlying query,
as well as a bunch of postprocessing. I doubt that the approach you seem
to be using here can handle such cases.

I think you have also stomped all over the semantics of
query-buffer-related commands that are executed in the vicinity of a \d.
Up to now, \d didn't change the query buffer. That has its uses, eg

select somecol
\dt some* -- how's that table spelled again?
from sometable;

We could maybe think about making it work by moving the \watch repetition
up a level, so that exec_command() as a whole would be repeated ... but
I wonder what people would think repetition of other commands such as \i,
\e, \r, \if, etc etc should mean.

On the whole I think this is not a can of worms I want to open. There's
a clear distinction right now between plain SQL and backslash commands,
and this is going to fuzz that in ways that are hard to predict the
consequences of.

regards, tom lane